Shortly after their formation, Sun-like stars are quickly surrounded by a short-lived protoplanetary disk consisting of cool dust and gas inherited from the molecular cloud. The material present in the protoplanetary disk during this transient epoch represents the nucleosynthetic make-up of planetary systems. Solar System materials record nucleosynthetic isotope variability for several elements, commonly interpreted to reflect the heterogeneous distribution of stardust from different stellar sources in the protoplanetary disk. This nucleosynthetic variability can be used to trace the formation and secular evolution of primordial disk reservoirs, including the origin and nature of the material precursor to terrestrial planets. However, this requires a full understanding of the origin of the Solar System’s nucleosynthetic variability, including the nature of the carrier phases of nucleosynthetic anomalies and how volatility-driven disk processes may modulate the nucleosynthetic make-up of planetary precursors. Moreover, accretion processes and disk dynamics can also affect the nucleosynthetic variability recorded by planetary bodies. The aim of this session is to bring together scientists from various disciplines to further our understanding of the early evolution of protoplanetary disks, the origin of planetary precursors and the formation pathways of terrestrial planets. We welcome contributions from all fields of planetary sciences, including cosmochemistry, experimental petrology, theoretical astrophysics, astronomical observations, and numerical modeling.

New organics are continuously discovered as space missions explore the interstellar medium, comets, planetary bodies, icy moons, planets, … their surface and interior. The evaluation of this pool of organic carbon from which life has emerged on Earth and potentially elsewhere is central to our search for extraterrestrial life, as those molecules also represent an organic background that needs to be taken into account and not overinterpreted. The road to life likely includes reaction of such organics in water, rocks or minerals under a variety of thermodynamic conditions. This session welcomes contributions presenting the diversity of abiotic organics analyzed in meteorites, asteroids, icy bodies, on Mars, Earth, as well as experimental and theoretical work under a variety of conditions.

During the last decade, our understanding of the early geological and geochemical history of Mars has made great advances thanks to the study of new Martian meteorites (including the first Noachian regolith breccia), continued high-resolution mapping efforts using orbital instruments, and the activities of several new surface missions. In particular, NASA’s latest Mars rover, Perseverance, is equipped with a suite of instruments capable of submillimeter-resolution analyses (PIXL, SHERLOC and SuperCam) that enable characterization of the chemical, mineralogical and organic compositions of Martian rocks at an unprecedented level of detail. This mission is also the first step of the long-awaited Mars Sample Return campaign.

In this session, we welcome a diversity of contributions (including works based on laboratory experiments and Earth analogs) that explore the geochemical and mineralogical records of Mars throughout its early history and bring new insights into the dynamic geological processes that have shaped its ancient surface.

NOTE: This live event includes sessions 1cO2 and 4eO1, in that order, with no break between them.

This session aims to celebrate the scientific achievements and groundbreaking discoveries made by Professor Bernard Marty throughout his distinguished academic career. Bernard Marty’s research, by investigating the elemental and isotopic compositions of volatile elements (H, C, N, and noble gases) in a wide range of objects (from comets to the deep Earth) has produced seminal results across the many disciplines of geochemistry, some of which are listed below. One of his most notable achievements has been to use noble gases to provide new constraints on the fluxes of carbon and nitrogen between Earth’s interior and its surface environment to better understand the global carbon cycle. Recent discoveries by Bernard and his group at CRPG in Nancy have also demonstrated the variable contributions that solar gas, meteorites and comets have made to the budget of volatile elements on Earth. Bernard has also been a pioneer in paleo-atmospheric studies, and has strived to better understand how the composition of the atmosphere has evolved through time, from the Archean to the present-day. Original contributions in geochemistry and cosmochemistry, as well as transversal disciplines of Earth and planetary sciences, are welcome for this session with a strong focus on the understanding of the distribution of all volatile elements (CHNOPS, noble gases) in the solar system, and the exchanges of volatile elements between reservoirs of terrestrial planets over geological timescales. Contributions from early career researchers and underrepresented groups are strongly encouraged, and we aim to propose a session promoting diversity and inclusion.

NOTE: This live event includes sessions 1d03 and 2dO1, in that order, with no break between them.

Planetary materials constitute the prime sample targets to understand the origin and evolution of the Solar System from the formation of the first solids to planets. This session welcomes contributions that address current advances in Solar System research from studies on extraterrestrial and experimental materials, and associated dynamical models. We also encourage submissions related to the analysis of samples returned by space missions from Apollo to Hayabusa2, including those related to the characterization, curation, or preparation of planetary samples and methodology development for their analyses. Another emphasis is given on micrometeorites and Interplanetary Dust Particles (IDPs) analysis.

After the detection of more than 5000 exoplanets during the past three decades, new and upcoming advanced telescopes aim to unveil the chemistry of the atmospheres of terrestrial-type exoplanets, potentially including a handful of habitable zone planets. Molecules made of C, H, N, O, and S elements are expected to be the first ones to be detected from the atmosphere of Earth-sized exoplanets. One of the main objectives of this theme is “planetary habitability, which defines the physicochemical conditions at the surface of a planet required for life to develop”. Since first suggested, numerous reports about probiotic synthesis under CO atmospheres and its implications for the origins of life have been reported. Additionally, atmospheres with a variety of carbon redox state (CO₂/CO/CH₄) have been suggested as an intermediary step in the evolution of rocky planets. Some key questions are: How do the surface and interior of a planet affect the atmosphere chemistry? What are the implications on the origin of life as we know it?

This session brings together planetary and exoplanet scientists specializing in various domains including interior-atmosphere coupling, planetary redox states, ocean-atmosphere interactions, ocean chemistry, atmosphere radiative transfer, thermochemical equilibrium and kinetics, photochemistry, experimental petrology, isotope and chamber studies, volatile cycling, geochemical cycling, habitable zone climates, geodynamics and thermal evolution, to address exoplanet atmospheric characterization, interior-surface-atmosphere interactions, and planetary habitability

This session will provide a fertile ground for scientists from multiple disciplines where ideas and findings from one field can inform, influence, and promote other fields.

The chemical compositions of planetary bodies record their modes of accretion and differentiation. Refractory (e.g., Al, Ca, REE) and major (Mg, Fe, Si) elements are typically assumed to be present in near-chondritic ratios in planetary bodies. Small deviations, however, suggest early Solar System processes caused detectable fractionation among them. Conversely, the abundances of moderately volatile elements (e.g., K, Cu, Zn, Ga, Ge, Rb), siderophile volatile elements (e.g., Cu, Ag, S, Se, Te) and siderophile elements (e.g., Mo, W, Os) are shown to vary widely in rocky bodies.

The goal of this session is to quantify the abundances and isotopic compositions of these elements in planetary reservoirs, as well as in chondrite and achondrite groups, and the processes that modified them. The temporal and spatial evolution of Solar System reservoirs has important implications for understanding the accretion of the Earth and other planetary bodies. Processes affecting the elemental and isotopic compositions in the accessible portions of such bodies include collisional accretion, core-mantle differentiation, late accretion, impact volatilization, magma ocean outgassing and evolution, deep volatile cycling, and atmospheric losses. Moreover, the distribution and magnitude of nucleosynthetic isotope variations in meteorites record the history and variety of stellar sources that may have contributed to the volatile inventory of inner Solar System bodies.

We invite contributions across all disciplines of the planetary sciences, including experimental petrology and geophysics, analytical geo- and cosmochemistry, numerical modelling, and observations from solar system bodies and exoplanets. We encourage submissions from early career researchers and underrepresented groups.

The chemical compositions of planetary bodies are record of the modes of their accretion and differentiation. Whilerefractory (e.g., Al, Ca, REE) and major (Mg, Fe, Si) elements are typically assumed to be present in near-chondritic ratios in planetary bodies, small deviations, both among chondrites and their components, suggest early Solar System processes caused detectable fractionation among them. Conversely, the abundances of moderately volatile elements (MVE, e.g., K, Cu, Zn, Ga, Ge, Rb) are shown to vary widely in rocky bodies, however, the timing, location and conditions that they were lost from such bodies are a matter of debate.

 The goal of this session is to quantify the abundances and both the stable and nucleosynthetic isotopic compositions of these elements in planetary reservoirs, as well as in chondrite and achondrite groups. The temporal- and spatial evolution of Solar System reservoirs has important implications for understanding the accretion of the Earth and other planetary bodies. Processes affecting elemental- and isotopic compositions in the accessible portions of such planetary bodies include late accretion, core-mantle differentiation, magma ocean outgassing and evolution, deep volatile cycling and atmospheric losses. Moreover, the distribution and magnitude of nucleosynthetic isotope variations in meteorites record the history and variety of stellar sources that may have contributed to the volatile inventory of inner Solar System bodies.

We invite contributions from all domains of planetary sciences, including but not limited to, experimental petrology, isotope cosmochemistry, geochemistry and astrophysics applied to Earth, other terrestrial planets and various rocky bodies in our Solar System.

Sub-millimeter extraterrestrial dust particles are the main source of extraterrestrial matter on our planet. They have been accreted by the Earth since its formation, with the oldest fossil micrometeorites reported to have accumulated 2.7 billion years ago. This valuable reservoir of extraterrestrial materials can provide information about the solar system formation, the past dust flux, the timing of asteroid family formation, the past composition of the Earth’s upper atmosphere, and the diagenesis of sedimentary rocks. This session will highlight the value of ongoing analyses of existing fossilized and modern dust samples and present strategies for new cosmic dust collections to advance our understanding of early solar system materials and the geological history of the local solar system events. Topics may include but are not limited to mineralogical, chemical, and isotopic analysis of dust particles and collection techniques and strategies. We encourage contributions from laboratory analysis and theoretical models, as well as those from the perspectives of avant-garde initiatives for cosmic dust collections.

Planetary materials constitute the prime sample targets to understand the origin and evolution of the Solar System from the formation of the first solids to planets. This session welcomes contributions that address current advances in Solar System research from studies on extraterrestrial and experimental materials, and associated dynamical models. We also encourage submissions related to the analysis of samples returned by space missions from Apollo to Hayabusa2, including those related to the characterization, curation, or preparation of planetary samples and methodology development for their analyses.

With the success of the TESS mission and ground-based observational programs such as CARMENES and TRAPPIST in detecting terrestrial-mass planets in the habitable zone, and the advances in observations of protoplanetary disks, the search for habitable planets has growing impetus. There are now many Earth-class and super-Earth planets that could be potentially habitable, some of them so convincingly that they are considered as viable targets for JWST. The diversity of these planets, combined with our new understanding of the chemical composition of protoplanetary disks, has raised fundamental questions regarding their formation, interior composition, and geophysical and atmospheric properties. For instance,

- How do habitable planets form?

- How would the chemical composition of the protoplanetary disk play a role in habitability?

- What is the possible atmospheric composition of a habitable planet?

- What are the geodynamical characteristics of habitable planets?

- How necessary is plate tectonics and how would it affect habitability?

- How do the characteristics of the central star play a role in the formation of habitable planets?

Answers to these questions require knowledge and expertise of their respective fields. We propose a session where experts in the disciplines of protoplanetary disks, planet formation, planetary interiors and planetary atmospheres come together to present their findings and discuss formation of habitable planets. We will plan for invited and contributed talks, as well as poster presentations. This session will be open to all members of the research community. In particular, we will encourage the participation of junior scientists.

One of the main objectives in this theme is “planetary habitability, which defines the physicochemical conditions at the surface of a planet required for life to develop”. Since first suggested, numerous reports about probiotic synthesis under CO atmospheres and its implications for the origins of life have been reported. Additionally, atmospheres with a variety of carbon redox state (CO₂/CO/CH₄) have been suggested as an intermediary step in the evolution of rocky planets.

The session proposed here focuses on how stablish a rationale for the formation, evolution, and atmospheric properties of worlds with a variety of CO₂/CO/CH₄ atmospheres and carbon compounds formed in the atmosphere are recycled on terrestrial planets. Topics compatible with this session:

• Planet formation and evolution to different carbon redox states atmospheres.
• Atmospheric photochemistry under CO₂/CO/CH₄-rich atmospheres, specifically what type of organic molecules are formed at each environment.
• How geological observations and experimental techniques such as isotopes and chamber studies can elucidate carbon redox state in the atmospheres of Early Earth and Mars.
• Models of spectra of rocky exoplanets, their atmospheric composition and how these atmospheres can produce probiotic organics.
• Geochemical cycles of CO-rich atmospheres and their ocean-atmosphere interactions.

The proposed session is planned to provide a fertile ground for scientists from multiple disciplines where ideas and findings from one field can inform, influence, and promote other fields.

Relevance to other themes: The topics covered in themes 8, 9, and 10 are related to the ones proposed in this session.

This session aims to celebrate the scientific achievements and groundbreaking discoveries made by Professor Bernard Marty throughout his distinguished academic career. Bernard Marty’s research, by investigating the elemental and isotopic compositions of volatile elements (H, C, N, and noble gases) in a wide range of objects (from comets to the deep Earth) has produced seminal results across the many disciplines of geochemistry, some of which are listed below. 

One of his most notable achievements has been to use noble gases to provide new constraints on the fluxes of carbon and nitrogen between Earth’s interior and its surface environment to  better understand the global carbon cycle. Recent discoveries by Bernard and his group at CRPG in Nancy have also demonstrated the variable contributions that solar gas, meteorites and comets have made to the budget of volatile elements on Earth. Bernard has also been a pioneer in paleo-atmospheric studies, and has strived to better understand how the composition of the atmosphere has  evolved through time, from the Archean to the present-day.

Original contributions in geochemistry and cosmochemistry from all researchers in the community are welcome for this session with a strong focus on the understanding of the distribution of all volatile elements (CHNOPS, noble gases) in the solar system, and the exchanges of volatile elements between reservoirs of terrestrial planets over geological timescales. Contributions from early career researchers and underrepresented groups are strongly encouraged, and we aim to propose a session promoting diversity and inclusion.

Siderophile (e.g., Mo, W, Os) and siderophile volatile elements (e.g., Cu, Ag, S, Se, Te), and their stable isotope signatures, are key tracers of processes during planetary evolution. These processes include condensation in the planetary nebula, differentiation of planetary embryos, core formation, evaporation from magma oceans, impact volatilization, and volcanic degassing. In this session we aim to bring together interdisciplinary contributions to shed light on the behavior of these chemical elements and their importance as chemical tracers across geo- and cosmochemical reservoirs. We invite contributions across disciplines of the planetary sciences, including experimental petrology and geophysics, analytical geo- and cosmochemistry, numerical modeling, and observations from solar system bodies and exoplanets. We encourage submissions from early career researchers and underrepresented groups.

After the detection of more than 5000 exoplanets during the past three decades, new and upcoming advanced telescopes aim to unveil the chemistry of the atmospheres of terrestrial-type exoplanets,  potentially including a handful of habitable zone planets. Moreover, with unprecedented data from current telescopes and planned missions to the moons in the outer Solar System whose sub-surface oceans may be habitable, the knowledge of the chemical signatures on moons is more vital than ever. Some of the key questions are: How do the surface and interior of a planet or a moon affect the atmosphere chemistry? What are the implications on the origin of life as we know it? The aim of this session is to bring together planetary and exoplanet scientists specializing in various domains including interior-atmosphere coupling, atmosphere radiative transfer, thermochemical equilibrium and kinetics, photochemistry, ocean chemistry, experimental petrology, volatile cycling, geochemical modelling, geodynamics and thermal evolution, to characterize atmosphere-surface-interior interactions of chemically diverse (exo)planets and moons.

After the detection of more than 5000 exoplanets during the past three decades, new and upcoming advanced telescopes aim to unveil the chemistry of the atmospheres of terrestrial-type exoplanets,  potentially including a handful of habitable zone planets. Moreover, with unprecedented data from current telescopes and planned missions to the moons in the outer Solar System whose sub-surface oceans may be habitable, the knowledge of the chemical signatures on moons is more vital than ever. Some of the key questions are: How do the surface and interior of a planet or a moon affect the atmosphere chemistry? What are the implications on the origin of life as we know it? The aim of this session is to bring together planetary and exoplanet scientists specializing in various domains including interior-atmosphere coupling, atmosphere radiative transfer, thermochemical equilibrium and kinetics, photochemistry, ocean chemistry, experimental petrology, volatile cycling, geochemical modelling, geodynamics and thermal evolution, to characterize atmosphere-surface-interior interactions of chemically diverse (exo)planets and moons.

New organics are continuously discovered as space missions explore the interstellar medium, comets, planetary bodies, icy moons, planets, ... their surface and interior. The evaluation of this pool of organic carbon from which life has emerged on Earth and potentially elsewhere is central to our search for extraterrestrial life, as those molecules also represent an organic background that needs to be taken into account and not overinterpreted. The road to life likely includes reaction of such organics in water, rocks or minerals under a variety of thermodynamic conditions. This session welcomes contributions presenting the diversity of abiotic organics analyzed in meteorites, asteroids, icy bodies, on Mars, Earth, as well as experimental and theoretical work under a variety of conditions.

Impacts play a crucial role in the growth and evolution of planetary bodies of all sizes from dust to planets. Determining how collisions during accretion affect the composition and thermal state of bodies and their surfaces is therefore critical to building an understanding of planet formation. We invite abstracts from theorists, experimentalists, observers, and modellers, working in all fields ranging from geochemistry to astrophysics, who are interested in planetary impacts and their direct or indirect consequences.

The main objectives in conducting the present studies are to minimize the cost of investigation and to maximize the results for analyzing and evaluating the quality and availability of groundwater researches. Climate change is “a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods.

Climate fluctuations are not unusual. In the North Atlantic Sector, for example, it is well known that the average temperatures and winds can fluctuate on decadal time scales. Climate changes caused by humans (anthropogenic) also evolve over the course of several decades. The natural decadal changes and those caused by humans are therefore superimposed upon one another. This makes it difficult to assess the impact of humans on climate with certainty. And also, proper understanding of the problem (Fluoride) of relation between geology, distribution, it is also proposed to investigate different aspects like land use and land cover, rainfall, climate, evapotranspiration, runoff, infiltration and water level fluctuation.

The fate of life-essential volatile elements (C, H, N, O, P, S)

The fate of life-essential volatile elements (C, H, N, O, P, S)

Deep mantle volatiles play a major influence on Earth’s dynamics as they control large-scale differentiation events. They record a breadth of events, including mantle degassing, exchange with Earth’s surface, the formation of Earth’s atmosphere, and the maintenance of habitability. To understand the role of deep mantle volatiles (H, C, N, S, noble gases and the halogens) in shaping the Earth from its origin to present-day, it is necessary to assess their abundances and isotopic compositions in the mantle and the core. The aim of this session is to bring together expertise from the different fields of planetary sciences studying volatiles to foster interdisciplinary discussions. Through this session, we call contributions related to the formation of deep Earth volatile reservoirs. We invite discussions on elemental and isotopic behavior of volatiles during core-mantle interactions, magma ocean degassing, long-term cycling of volatiles associated with plate tectonics and constraints on the timing of these processes. To this end, we invite contributions from all domains of planetary sciences, including but not limited to, isotopic geochemistry, experimental petrology and numerical modelling. Submissions from early-career scientists and under-represented groups are strongly encouraged.

Melts play a fundamental role in dynamic planetary interiors' physical, thermal, and chemical evolution. They significantly impact a wide range of fundamental properties relevant to the crust, mantle, and core. These fundamental properties include transport properties (e.g., diffusivity, viscosity, electrical conductivity), density contrast/buoyancy, and large-scale chemical differentiation. Thus, understanding the role of melts in the formation, differentiation, and evolution of planetary interiors requires insight into the atomistic scale behaviour of melts at extreme conditions, pressures, temperatures, and oxidation states (fO₂). This session aims at bringing together a wide variety of solid Earth sub-disciplines including geophysics, geodynamics, geochemistry, petrology, volcanology, and mineralogists. The session will be an excellent forum to present the latest research on the physicochemical properties of melts, from the atomistic to planetary scale, and relevant topics may include, but are not limited to: the structure and physical properties of melts, thermodynamic modeling, partial melting, and phase relations, liquid-solid partitioning, novel experimental approaches, or geophysical detection of melt distribution in (Exo)planetary interiors.

Carbon and hydrogen are fundamental components of geological fluids, which drive several environmental issues, such as the alteration of the surface carbon budget, ocean acidification, and greenhouse effects leading to an increase of the mean annual global temperatures with cascading effects on all ecosystems. However, the relevant geochemical processes in the deep Earth involving carbon and hydrogen may compete with each other in determining the pathways of either capture or mobilisation of C-O-H compounds, with profound implications on carbon-hydrogen budgets in space and time. It becomes then urgent to characterise the geo-biochemical patterns and rates of the selected natural carbon and hydrogen storage processes, acting at different structural levels within the lithosphere and mantle, and to determine the key conditions controlling their competing behaviours.
This session aims at bringing together multi-scale, cross-disciplinary studies combining natural, laboratory experimental and numerical approaches, providing key missing information on how conventional and newly established processes involving C-O-H fluids and their by-products act from the sub-micron to the macro scale.

NOTE: This live event includes sessions 2cO1 and 2gO1, in that order, with no break between them.

Our knowledge of planetary interiors is in large part built on the composition of surface rocks, whether from samples collected or analyzed in situ, from meteorites, or from remote measurements. A large quantity of data has been or will be acquired for the Earth but also Mercury, Mars, Venus, the Moon and asteroids, through space missions and the study of meteorites. More recently, developments in astronomy have brought new constraints on the structure and composition of exoplanets. These data sets and their integration into diverse models enable us to unravel the internal structure, composition, and evolution of planetary bodies in the solar system and beyond. In this session, we invite contributions from all disciplines of planetary sciences, including, but not limited to, cosmochemistry, experimental petrology, geophysics, numerical modeling, meteoritics and astronomy. By bringing together scientists from diverse fields, we aim to draw up an inventory of our current knowledge of planetary interiors as constrained by extraterrestrial samples and space data.

NOTE: This live event includes sessions 1d03 and 2dO1, in that order, with no break between them.

The composition of volatiles of indigenous and recycled origin is strongly influenced by pressure, temperature, composition and oxygen fugacity, thereby impacting the density, rheology, melting behavior, and consequently differentiation of the Earth’s mantle. This session seeks to elucidate, through interdisciplinary studies, variations in the deep-Earth volatile cycling across space and time during mantle metasomatism and intraplate magmatism. This includes, but is not limited to, (1) mantle xenoliths and xenocrysts, including diamonds and their inclusions, which provide a direct record of such deep volatiles; (2) complementary information delivered by mantle-derived magmas emplaced in intraplate settings (e.g. carbonatites, kimberlites, alkaline basalts), including their isotopic compositions; and (3) experimental studies, and geodynamic-geochemical modeling of the physico-chemical conditions and processes mediated by deep-Earth volatiles, and their link to tectonomagmatic events at all spatio-temporal scales.

The presence of heterogeneities in the Earth’s solid interior has important implications relevant to many disciplines of modern geosciences, from studies illuminating the chemical evolution of our planet to the cycling of elements essential to life and mineral resources. The growing body of available data and the development of novel geochemical techniques make studies of mantle compositions, via mantle-derived melts or mantle xenoliths, powerful tools to infer the spatiotemporal scales of mantle heterogenities. In this multi-disciplinary session, petrological, geochemical and isotopic studies of natural and experimental samples as well as contributions from geophysical methods are welcome, and insights from numerical modelling are strongly encouraged. Among the topics targeted here are (1) the origin and nature of geochemical reservoirs in the solid Earth; (2) the long-term evolution of these reservoirs in subduction, ridge and intraplate settings; (3) the length scale of mantle heterogeneities and their impact on mantle dynamics, melting and volcanism; (4) the rheological consequences of the presence of heterogeneities for the deformation of mantle and crustal material, and their implications on global tectonics and magmatism, from the mantle to the crust.

NOTE: This live event includes sessions 5cO3 and 2fO1, in that order, with no break between them.

The crystallization of the magma ocean and metal-silicate segregation of our planet, which leads to the formation of its core, is undeniably the most extreme differentiation that Earth has undergone. However the links between these processes and their long-term effects on the evolution of the Earth and rocky planets have remained poorly understood. For decades, for instance, the existence of core-mantle interactions has been hotly debated, and it is often assumed that the Earth’s core has remained isolated since its formation. Thanks to advances in sample analysis, experiments at extreme conditions and modelling, we have an increased understanding of these processes and their role in planetary evolution. For this interdisciplinary session  we invite contributions from fields including, but not limited to: (isotope) geochemistry, geochronology, fluid and geodynamics, magnetism, experimental petrology and mineral physics. We invite presentations addressing topics such as earliest differentiation of the Earth (and rocky planets, including metal-silicate equilibration and interaction, the creation of dynamic magnetic fields, the solidification and crystallisation of initially molten planets, interactions across the core-mantle boundary  or the preservation and significance of primordial heterogeneities.

NOTE: This live event includes sessions 2cO1 and 2gO1, in that order, with no break between them.

Thanks to advances in sample analysis, experiments at extreme conditions and modelling, we have an increased understanding of the role that accretion, differentiation, magma ocean crystallisation and degassing and core-mantle interaction play in planetary evolution. However the links between these processes and their long-term effects on the evolution of rocky planets within and beyond our solar system remain poorly understood. For this interdisciplinary session we invite contributions from fields including, but not limited to: (isotope) geo- and cosmochemistry, geochronology, fluid and geodynamics, magnetism, experimental petrology and mineral physics. We invite presentations addressing topics such as earliest differentiation of rocky planets and exoplanets, including metal-silicate equilibration and interaction, the creation of dynamic magnetic fields, the solidification and crystallisation of initially molten planets and the evolution of their atmospheres and hydrospheres, the preservation and significance of primordial heterogeneities and late accretion.

Thanks to advances in sample analysis, experiments at extreme conditions and modelling, we have an increased understanding of the role that accretion, differentiation, magma ocean crystallisation and degassing and core-mantle interaction play in planetary evolution. However the links between these processes and their long-term effects on the evolution of rocky planets within and beyond our solar system remain poorly understood. For this interdisciplinary session we invite contributions from fields including, but not limited to: (isotope) geo- and cosmochemistry, geochronology, fluid and geodynamics, magnetism, experimental petrology and mineral physics. We invite presentations addressing topics such as earliest differentiation of rocky planets and exoplanets, including metal-silicate equilibration and interaction, the creation of dynamic magnetic fields, the solidification and crystallisation of initially molten planets and the evolution of their atmospheres and hydrospheres, the preservation and significance of primordial heterogeneities and late accretion.

The presence of heterogeneities in the Earth’s solid interior has important implications relevant to many disciplines of modern geosciences, from studies illuminating the chemical evolution of our planet to the cycling of elements essential to life and mineral resources. This session aims to bring together multi-disciplinary approaches tackling the development of physico-chemical heterogeneities as well as their effect on mantle dynamics and magmatism, from the mantle to the crust. Petrological, geochemical and isotopic studies of natural and experimental samples as well as contributions from geophysical methods are welcome, and insights from numerical modelling are strongly encouraged. Among the topics targeted here are (1) the origin and nature of geochemical reservoirs in the solid Earth; (2) the long-term evolution of these reservoirs in subduction, ridge and intraplate settings; (3) the length scale of mantle heterogeneities and their impact on mantle dynamics, melting and volcanism; (4) the small-scale processes governing fluid-melt migration and interaction with minerals; (5) the rheological consequences of the presence of heterogeneities for the deformation of mantle and crustal material, and their implications on global tectonics and geodynamics.

Geochemical investigations of oceanic basalts provide critical insights on the compositional heterogeneity and geodynamical history of Earth’s mantle. The growing body of available data and the development of novel geochemical techniques make studies of mantle compositions, mainly via mantle-derived melts, powerful tools to infer the spatiotemporal scales of mantle convection and possibly compositionally distinct reservoirs themselves. However, the nature of this approach is often indirect and requires an accurate understanding of how such heterogeneity is ultimately reflected by the chemical and isotopic signatures of lavas, which record melting processes and melt aggregation as well as source signatures. By contrast, mantle xenoliths provide more direct geochemical and isotopic information about some portions of the mantle and how it is melted. Localized and broad-range studies of these materials inform our models of small-scale convection in the upper mantle, whole-mantle convection, and plume dynamics, as well as the importance of the tectonic setting (plume, ridge, plume-ridge system, etc.) and associated processes when translating geochemical observations in terms of mantle source. We welcome contributions exploring the development of mantle heterogeneities from chemical, isotopic, and mineralogical perspectives, transport through the convecting mantle, and the challenges of inferring mantle composition, dynamics, and processes from lava and xenolith geochemistry. Multidisciplinary studies combining geochemical observations with insights from seismology, geodynamics, and experimental petrology are also encouraged.

The metal-silicate segregation of our planet, leading to the formation of its core, is undeniably the most extreme differentiation that Earth has undergone. This differentiation left the planet with a boundary between its metallic core and silicate mantle, which hosts Earth’s greatest contrasts in chemistry, density, and viscosity. For decades, the existence of core-mantle interaction has been hotly debated, and it is often assumed that the core has remained isolated since its formation. Novel techniques, however, are providing exciting new insights into the existence of core-mantle interactions. Although unequivocal evidence for exchange has been difficult to find, some geochemical tracers potentially provide evidence for this process. We welcome contributions from interdisciplinary studies that utilize innovative ways to investigate interactions across the core-mantle boundary. These include geochemistry, geodynamics, geophysics, and high-pressure mineral physics; and using observational, experimental, numerical, or theoretical approaches.

A lot of effort has been made during the preceding decades to decipher the nature of metasomatism and its connection to the geochemical evolution of the continental lithosphere. The most direct expressions of metasomatism at the surface are found in mantle xenoliths and alkaline magmas (e.g., carbonatites, kimberlites, alkaline basalts). Their study improved our understanding as they provide a unique window into the mantle and the formation processes. However, many issues regarding metasomatism still remain unclear, not well constrained, and inadequately quantified. For example, partial melting/fractional crystallisation of which kind of metasomatized lithospheric mantle leads to the formation of these alkaline magmas? What are the melting relations and reactions of such mantle sources? What is the role of volatiles (OH, C, S, N, P, halogens) in the metasomatism of the lithosphere and the generation of alkaline magmas? How fluids, melts and fO₂ are related to metasomatic reactions and the chemical budget (e.g., volatiles, REE) of the continental lithosphere? How do plate tectonics affect or control mantle metasomatism (and associated magmatism) in continental intraplate settings? Only by addressing questions like these we can improve our understanding about metasomatism and establish the connection with the formation and geochemical evolution of the continental lithosphere.

In this session, we welcome contributions that address the above-mentioned problems through field observations, experimental and geochemical studies, and theoretical modelling. The aim of this session is to bring together researchers investigating various aspects of metasomatism of the continental lithosphere. Interdisciplinary contributions and experimental studies are especially encouraged.

The composition of volatiles of indigenous and recycled origin is strongly influenced by pressure, temperature, composition and oxygen fugacity, thereby impacting the density, rheology, melting behavior, and consequently differentiation of the Earth’s mantle. This session seeks to elucidate, through interdisciplinary studies, variations in the deep-Earth volatile cycling across space and time. This includes, but is not limited to, (1) mantle xenoliths and xenocrysts (including diamonds and their inclusions), which provide a direct record of such deep volatiles; (2) complementary information delivered by mantle-derived magmas emplaced in intraplate settings, including their isotopic compositions; and (3) experimental studies, and geodynamic-geochemical modeling of the physico-chemical conditions and processes mediated by deep-Earth volatiles, and their link to tectonomagmatic events at all spatio-temporal scales.

The composition of volatiles of indigenous and recycled origin is strongly influenced by pressure, temperature, composition and oxygen fugacity, thereby impacting the density, rheology, melting behavior, and consequently differentiation of the Earth’s mantle. This session seeks to elucidate, through interdisciplinary studies, variations in the deep-Earth volatile cycling across space and time. This includes, but is not limited to, (1) mantle xenoliths and xenocrysts (including diamonds and their inclusions), which provide a direct record of such deep volatiles; (2) complementary information delivered by mantle-derived magmas emplaced in intraplate settings, including their isotopic compositions; and (3) experimental studies, and geodynamic-geochemical modeling of the physico-chemical conditions and processes mediated by deep-Earth volatiles, and their link to tectonomagmatic events at all spatio-temporal scales.

Our knowledge of planetary interiors is in large part built on the composition of surface rocks, whether from samples collected or analyzed in situ, from meteorites, or from remote measurements. A large quantity of data has been or will be acquired for the Earth but also Mercury, Mars, Venus, the Moon and asteroids, through space missions and the study of meteorites. More recently, developments in astronomy have brought new constraints on the structure and composition of exoplanets. These data sets and their integration into diverse models enable us to unravel the internal structure, composition, and evolution of planetary bodies in the solar system and beyond. In this session, we invite contributions from all disciplines of planetary sciences, including, but not limited to, cosmochemistry, experimental petrology, geophysics, numerical modeling, meteoritics and astronomy. By bringing together scientists from diverse fields, we aim to draw up an inventory of our current knowledge of planetary interiors as constrained by extraterrestrial samples and space data.

Chalcophile and siderophile elements have long been used as key tracers for such processes as planetary formation and differentiation, mantle melting and fractionation, and crust formation and evolution. These geochemical messengers also have a strong economic importance as critical and strategic metals and their exploration, production and recycling increase every year. Some of these heavy elements are highly toxic for the biota and pose a growing threat for the environment through mining and ore processing.

This session invites geochemical, mineralogical, petrological, analytical, experimental, modeling, and interdisciplinary studies that aim to interpret and examine the geochemical behaviour, global abundances and cycles, isotopic compositions, and chemical and redox speciation of chalcophile and siderophile elements in nature and laboratory across the wide range of conditions and scales, from the mantle to the Earth’s surface.

Geochronology provides the temporal framework for the study of geologic processes. As such it is a cornerstone for many Earth Sciences disciplines, providing the data necessary to determine the rates and durations of the processes that shape our planet. Due to the continuous advancement of analytical capabilities, today’s geochronologists can choose from a range of established and recently developed methods. The improved accuracy, precision, and spatial resolution of established methods, in conjunction with recent methods such as Raman dating, reaction cell mass spectrometry, or multi-method thermochronology provide a level of detail and complexity in geochronological investigations that is unprecedented.
This session seeks to provide an overview of the current status of geochronological methods and their applications. We thus welcome contributions about analytical improvements, developments in standardisation, innovative data reduction strategies, novel applications, and multi-chronometer studies.

The evolution of the Earth’s interior, surface and atmosphere are inextricably linked through degassing, weathering, and the recycling of surface material back into the mantle. This makes the sedimentary rock record one of the most valuable archives to study the early Earth, allowing us to investigate the co-evolution of the geosphere, surface environments and the atmosphere. The characterization of detrital, biogenic, and chemical sediments in terms of elemental concentrations, stable and radiogenic isotope systems, or noble gases has provided key insights into the evolution of the mantle, the extraction and composition of continental crust, and the “degassing and regassing” of the solid Earth.

This session welcomes contributions that use major and trace element analysis, as well as all types of isotope systems to study sediments and detrital minerals in order to investigate the evolution of the Earth mantle, crust and atmosphere during the Hadean, Archean and Proterozoic eons.

The complex evolution of the oceanic lithosphere since breakup must be unravelled if we would like to better understand the dynamics of Earth cycles, mantle convection, and plate motion. A comprehensive understanding of the evolution of the oceanic lithosphere requires consideration of different geotectonic contexts and structures, from basement reactivation, active mid-ocean ridges, aseismic ridges, oceanic plateaus, microplates, seamount ridges, continental crust fragments, including SCLM or exhumed mantle, as well as the structure and constitution of the continental margins and structural heritage.

The composition of the oceanic crust accreted along mid-ocean ridges depends not only on heterogeneous mantle sources, but also on the modalities of melt differentiation and migration during its ascent towards the surface, and the magmatic evolution and interaction through time, where migration potentially triggers melt reactions/interactions and, therefore, challenges historical models of melt differentiation.

In addition to crustal heterogeneities inherited from several factors previously discussed, other processes may increase the complexity of oceanic crust evolution. These include: active plumes, whose influence is a matter of debate, and extending to ancient delaminated continental crust, oceanic slabs dehydration, sediments input among others.

The results of geophysical, structural geological, tectonic, and petrological surveys are refreshing concepts, and linking mantle and crustal dynamics in oceanic regions is the focus of our session. This session will also focus on geodynamic reconstructions and the evolution of all oceanic crust records, including their conjugated margins, 'from birth to death'.

Ophiolites represent slices of ancient oceanic lithosphere emplaced during the assembly of supercontinents. The different lithologies associated with ophiolite complexes preserve valuable information about key issues, such as magmatic-metamorphic processes in the sub-oceanic mantle, tectonic processes from continental breakup and spreading initiation to ocean basin closure, formation of ore deposits, biogeochemical activity from ocean floor to the Earth’s surface and CO₂ sequestration. Ophiolites retain evidence of geochemical heterogeneity issued by mantle upwelling, melt transport and slab subduction through the geological periods. Mixing of different geochemical reservoirs led to formation of economic ore deposits (e.g., chromitites and VMHS) associated with ophiolites. The increasing number of research works, the amazing recent discoveries (e.g., exotic mineral assemblages in worldwide ophiolites and chromitites, identification of earliest ophiolites and podiform chromitites), and the development of analytical techniques have significantly improved our understanding of the ophiolite formation and hence the Earth’s evolutionary history. This session aims to bring together contributions related to origin and evolution of ophiolites, including petrological, mineralogical, geochemical, and experimental constraints, numerical modeling, and interdisciplinary research works.

Subduction-related processes have shaped the chemical signatures of the continental crust. The effects of subduction are also identified in mantle-derived lavas generated long after regional subduction has ceased, and are found imprinted on ocean island and spreading center basalts. Subduction-modified mantle lithosphere is often implicated as a magma source, and evidence for it is provided in mantle xenoliths. With advances in our understanding of sources, slab-mantle partitioning, mass transfer, and fluxes under volcanic arcs, it is timely to explore the nature and persistence of arc-related signatures across the spectrum of anorogenic settings. We also seek to more closely examine the fidelity of these records to processes that might have operated in now-defunct arc settings. Of particular interest are considerations of species that are often regarded as relatively fugitive, including water, carbon, halogens, and noble gases. We also invite contributions from theoretical considerations and experimental investigations, radiogenic and stable isotope tracing, as well as from case studies.

The complex evolution of the lithosphere can be studied with aspects of different geotectonic contexts and lithologies, which can serve a better understanding of the dynamics of Earth cycles, mantle convection, and plate motion. One of these aspects is the study of mantle xenoliths, which is a direct method to examine and understand geochemical mass balances, physical states and geodynamical processes occurring in the shallow subcontinental lithospheric mantle.

Lithological, textural, and geochemical knowledge obtained from fluid, silicate, carbonatite, sulfide inclusions together with hydrous and nominally anhydrous minerals occurring in upper mantle and crustal xenoliths, commonly hosted by alkali basalts, holds the key to understand fundamental processes in the Earth’s lithosphere. In addition to crustal heterogeneities inherited from several factors, other processes may increase the complexity of the subcontinental lithospheric evolution. These include, among others, the still debated influence of active plumes, ancient delaminated continental crust, dehydration of ancient oceanic slabs, and sediment input.

In the course of an illustrious career, Dr. Csaba Szabó has become one of the most eminent experts of the petrology and geochemistry of the lithospheric mantle and overlying crust in the Carpathian-Pannonian region in a large part through the use of inclusions in minerals and has also made important contributions to the environmental sciences. Through his vast knowledge, professional and pedagogical excellence, selflessness, and sacrifice, he became a cohesive force that has educated several generations of young, Hungarian and international scientists, now working in academia and industry in various corners of the world.

The study of mantle xenoliths is a direct method to examine and understand geochemical mass balances, physical states and geodynamical processes occurring in the shallow subcontinental lithospheric mantle. Lithologic, textural and geochemical knowledge obtained from fluid, silicate, carbonatite, sulfide inclusions together with hydrous and nominally anhydrous minerals occurring in upper mantle and crustal xenoliths, commonly hosted by alkali basalts, holds the key to understand fundamental processes in the Earth’s lithosphere.

In the course of an illustrious career, Dr. Csaba Szabó has become one of the most eminent experts of the petrology and geochemistry of the lithospheric mantle and overlying crust in the Carpathian-Pannonian region in a large part through the use of inclusions in minerals, and has also made important contributions to the environmental sciences. Through his vast knowledge, professional and pedagogical excellence, selflessness and sacrifice, he became a cohesive force that has educated several generations of young, Hungarian and international scientists, now working in academia and industry in various corners of the world.

Submissions to this session, celebrating the career of Dr. Csaba Szabó on the occasion of his retirement, are encouraged for oral and poster presentations by scientists and students of all career stages, whether or not they have worked or collaborated with Dr. Szabó.

NOTE: This live event includes sessions 3hO3 and 3gO1, in that order, with no break between them.

A defining characteristic of Planet Earth is its bimodal hypsometry; however, despite new-generation mass spectrometers, growing databases, and even new cratons being investigated, there is still no consensus about the timing and tempo of the growth of the continental crust, as well as when and how Earth's first continental crust became established. Over the last two decades, our understanding of processes governing the evolution of the early Earth’s (4.5 to 2.5 Ga) lithosphere and its resulting geochemical record has improved due to innovative advancements in geochemical analysis of some of the oldest available rocks. Novel chemical and isotopic proxies, allied to more traditional geological techniques, are continuing to afford us new insights into this important question. Recent advancements in the evaluation of geochemical data have highlighted the importance of interdisciplinary studies; we welcome contributions that utilise the gamut of novel geochemical approaches, coupled with important tools such as field observations, experiments, geochronology, petrology and modelling, for understanding Earth's early continental crust, including studies of timescales, as well as igneous, metamorphic and secondary alteration processes relating to the formation and establishment of this reservoir. We also welcome contributions that address the vexed question of how and why the formation of continental crust has varied over geological time.

NOTE: This live event includes sessions 3hO3 and 3gO1, in that order, with no break between them.

The Earth has experienced dramatic changes during its first two billion years. Both mantle and crust evolved in their composition and structure. Global recycling of the lithosphere has started and proceeded. The Earth’s continents started to form, melting of basaltic crust led to the formation of TTG's (tonalite-trondhjemite-granodiorite) following by multi-sourced granitoids. When and how did all these start? How important were mantle plumes and impacts in triggering large-scale lithosphere recycling (subduction?) on Earth? What was the rate of continental crust production in the Hadean and Archean Eons?

We welcome contributions on geochemical and petrological constraints and geodynamic models focused on global recycling on Earth, styles of global tectonics and their temporal evolution, the origin and relation of subduction to Archean crustal and mantle-derived rocks, and the Hadean/Archean record from refractory minerals such as olivine, chromite, zircon and diamond, and their hosted inclusions.

The origin and evolution of the Earth’s continental crust remain a hotly debated topic by geoscientists. The Earth’s continents started to form four billion years ago in the Archaean Eon and over time have drifted and eroded due to tectonic processes, leaving few remaining well-preserved rocks available to study. In the early Archaean, the main crust-forming process was the episodic melting of basaltic crust that led to the formation of TTG's (tonalite-trondhjemite-granodiorite). The changing geodynamics of the Earth in the Meso- to Neoarchaean (3.0-2.5 Ga) caused the appearance of multi-sourced granitoids.  These multi-sourced granitoids had contributions from the mantle and/or from pure crustal sources. We invite contributions that use geochemical, petrologic, and geodynamic approaches to address fundamental questions regarding crust-mantle interaction during the Archaean Eon.

The Earth has experienced dramatic changes during its first two billion years. Both mantle and crust evolved in their composition and structure. Global recycling of the lithosphere has started and proceeded. When and how did all these start? How important were mantle plumes and impacts in triggering large-scale subduction on Earth? What was the rate of continental crust production in the Hadean and Archean Eons?

We welcome contributions on geochemical and petrological constraints and geodynamic models focused on global recycling on Earth, styles of global tectonics and their temporal evolution, the origin and relation of subduction to Archean crustal and mantle-derived rocks, and the Hadean/Archean record from refractory minerals such as olivine, chromite, zircon and diamond, and their hosted inclusions.

A defining characteristic of Planet Earth is its bimodal hypsometry, yet debate still exists around when Earth's first continental crust became established, and the processes which led to its formation. Novel chemical and isotopic proxies, allied to more traditional geological techniques, are continuing to afford us new insights into this important question. We welcome contributions that utilise the gamut of geochemical approaches, coupled with important tools such as geochronology, petrology and modelling, for understanding Earth's early continental crust, including studies of timescales, as well as igneous, metamorphic and secondary alteration processes relating to the formation and establishment of this reservoir. We also welcome contributions that address the vexed question of how and why the formation of continental crust has varied over geological time.

Over the last two decades, our understanding of processes governing the evolution of the early Earth (4.5 to 2.5 Ga) lithosphere and its resulting geochemical record has improved due to innovative advancements in geochemical analysis of some of the oldest available rocks. However, despite new-generation mass spectrometers, growing databases, and even new cratons being investigated, there is still no consensus about the timing and tempo of the growth of the continental crust nor the onset of modern-style plate tectonics on the horizon. Apart from the scarcity of the geological record, a challenge lies in the uncertainty of geochemical and petrochronological data, often resulting in non-unique interpretations that, in turn, are difficult to assign to a single geologic event and/or geodynamic setting. Recent advancements in the evaluation of geochemical data have highlighted the importance of interdisciplinary studies, incorporating expertise from e.g., field observations, structural analysis, mineralogy and petrology, experiments, geodynamics or numerical approaches to reach coherent models for the early evolution of the crust-mantle system during the Hadean and Archean.

Here we invite contributions from (isotope) geochemistry but also aforementioned sister disciplines to present their research relevant to the evolution of the early Earth lithosphere and mantle.

Geochronological ages produced using high precision techniques are the backbone of the geosciences. Over the past few decades, these ages have become more and more precise, and studies have utilized this high precision by combining the ages with other geochemical, observational or structural information from the dated minerals. Combining these types of datasets has allowed us insights into numerous processes e.g.: i) understanding the petrogenesis of felsic magmatic systems, from the modern to Archean times; ii) correlating distal stratigraphic sections throughout geological time, which then can be used to relate sedimentary and biologic archives to processes (such as volcanic eruptions); iii) to determine the rates of metamorphic processes through detailed chemical and isotope studies of zoned minerals, or minerals in particular assemblages; iv) to estimate rates of ore forming processes. High precision geochronological techniques are often more destructive than in-situ techniques, but careful characterization of minerals combined with geochemical and isotopic analysis can combine the power of both in-situ and high precision techniques and allow us to correctly interpret geochronologic and geochemical datasets. Here we welcome studies that combine high precision geochronology with other tools to provide insight into our understanding of the temporal evolution of processes occurring in the crust. The combination of high precision geochronology with elemental and isotopic geochemistry and modelling approaches is something pioneered by Urs Schaltegger, and this session specifically encourages researchers who combine these techniques in innovative ways (as Urs has a history of doing) to gain new insights into crustal processes.

The burial and transformation of crustal rocks along subduction zones represents a key process for the differentiation and chemical evolution of Earth. Subduction zone metamorphism changes the physical properties of rocks and fluid-mediated element transfer from the slab to the mantle wedge is key for understanding mantle metasomatism and formation of new crust above subduction zones. In this session we invite contributions from studies of natural rocks, experiments, and modelling that help to constrain key processes that are associated with the metamorphism of subducted oceanic and continental crust. Topics may include slab geotherms - present and past, geochemical tracing of fluid-rock interactions at high pressure conditions, fluid-mediated mass transfer and trace element partitioning in slab lithologies, determination of geological rates, and deformation and the influence of metamorphism on the rheology of subducted rocks

Partial melting during (U)HT metamorphism and transfer of anatectic melts are key mechanisms that shape the chemical differentiation of continental crust and have a major impact on the tectonic evolution of orogens. Furthermore, partial melting has results in chemical and isotopic fractionation between minerals, fluids and melts thereby shaping the chemistry of metamorphic and igneous rocks.
However, the connection between the metamorphic source rock and the final solidified magmatic rock is often obscured by a multitude of potential processes during ascent and a lack of continued exposure from the source to the emplacement region. Many methods and tools have emerged to address these important but often-obscured processes. From classic approaches of detailed field and microstructures documentation of melt migration to advances in thermodynamic modelling of phase assemblages and chemistry, to micro-analysis of melt and fluid inclusions, and finally, to crustal-scale modelling of reactive flow process and magma transport through the crust. We invite contributions from metamorphic, igneous, and experimental petrology as well as numerical modelling dedicated to understanding metamorphism, partial melting, and magma generation and ascent in the continental crust.

NOTE: This live event includes sessions 4fO2 and 4cO1, in that order, with no break between them.

The formation of a differentiated stable crust is a crucial step in the Earth’s evolution towards a habitable planet. Metamorphic processes played a critical role in this transformation, turning primitive mantle-derived mafic rocks into buoyant felsic crust via complex dehydration, partial melting and fluid–rock interactions. Recent efforts have been made to investigate these processes occurring in the precursors to Archaean tonalite–trondhjemite–granodiorite (TTG) series rocks. Much of this early evolution is generally obscured by a billion-year-long polyphasic history of deformation, magmatism and metamorphism. As such, thermodynamic and geochemical modelling provides a means of interrogating ancient rocks regarding the processes responsible for their formation, with implications for early Earth geodynamics. Laboratory experiments provide additional information by replicating the conditions that have led to the emergence of the modern crust from its primitive building blocks. Combining these tools with novel stable and radiogenic isotope methods may enable us to trace material fluxes through the early lithosphere, and illuminate its tectonothermal history.

This session aims at combining observations of the rock record, geochemistry, experimental petrology and modelling approaches in order to further our understanding of the metamorphic processes that have contributed to the creation and stabilization of a habitable crust.

The process of metal enrichment has been observed in natural samples through the study of minerals, fluids and glasses, and validated in partitioning and solubility experiments. Volcanic gases and brines are commonly enriched in siderophile and chalcophile metals, and magma degassing can thus provide a flux of these metals to the crust if exsolved fluids are not outgassed to the atmosphere. However, the significance and magnitude of this flux are debated, because this apparent primary flux could rather be a redistribution within the crust. Recent work on metal fingerprints such as (metal) isotopes, noble gases, and volatiles is providing new insights into the ultimate sources of metals in magmatic-hydrothermal systems and their behavior. This session aims to provide a forum to discuss this topic and present new findings on metal mobility in the crust and the role of magmas and fluids in this. We invite contributions using natural samples, experiments and modelling.

NOTE: This live event includes sessions 1cO2 and 4eO1, in that order, with no break between them.

Serpentinites and metasomatized ultramafic rocks are found in a wide range of geological settings, and they play a key role in mineral-scale reaction, geochemical cycling, and plate tectonic-scale deformation. Their study allows us to better understand hydrothermal processes in sub-aerial alkaline springs, at mid-oceanic ridges, ocean-continent transitions, and in the slab and mantle wedge of subduction zones. Serpentinization is intimately linked to the production of H₂, CH₄, and higher carbon molecules, and causes extreme redox gradients, which are of primary importance for the formation of metal deposits and the emergence of life. Through hydration and carbonation at mid-oceanic ridges and along transform faults, serpentinites are a major carrier of volatiles into subduction zones. Their low density and unique rheological properties make serpentinites key factors for plate boundary deformation and interesting in seismicity studies.

This session encourages abstract submissions related to serpentinite and serpentinization in all contexts from Earth’s surface to subduction zones. We are looking forward to seeing contributions from studies of natural present-day and fossil serpentinites, ophiolites, experiments, and computational modeling showing the importance of these rocks on fluid-rock interactions, carbon mobility, redox conditions, H₂ production, but also their value in economy and industry (natural resources, carbon fixation).

NOTE: This live event includes sessions 4fO2 and 4cO1, in that order, with no break between them.

Tectonic processes drive dynamic changes in the crust that shape our planet. The interplay between fluids, deformation, and metamorphism controls the spatial and temporal scales of tectonic behaviour as well as the extents of chemical differentiation in the crust. Examining the rocks, minerals, and fluids involved in tectonic processes using a combination of thermodynamic modelling and state-of-the-art geochemical and isotopic techniques enables deeper insight into the coupling of geochemistry, petrology, and tectonics.

We invite contributions using geochemical and thermodynamic approaches to study a wide range of tectonic processes, from fluid-rock interactions in zones of deformation; permeability evolution and destruction in the crust; metamorphic and igneous processes such as anatexis in the crust; to modern-day tracing of temporal variations in geochemical systems (e.g., hot springs in tectonically active areas).

Stable isotopes (e.g. Li, B, O, Mg, Fe, Cu, Ni, Cr, K, Si) are unique tracers of both high- and low-temperature geochemical processes. With continually improving analytical capabilities, these isotope systems are becoming more frequently applied to unravel magmatic and metamorphic processes, such as melting and crystallization, crustal assimilation, solid-state reaction, devolatilization, diffusion, and metasomatism. In this session, we invite submissions focusing on stable isotope systems that: (1) utilize experimental and theoretical studies to contribute to our basic understanding of natural systems (e.g. isotopic fractionations, diffusion chronometry), (2) address scientific questions relating to how magmas evolve from their source to the surface (i.e. magma generation and differentiation), and (3) constrain the role of metamorphism in plate tectonics across pressure and temperature (e.g. natural hazards, orogenesis). Results of ongoing developments in analytical techniques and standardization are encouraged, as well as global syntheses across systems and timescales. We particularly invite contributions from early career researchers and those from groups that are underrepresented in the geoscience community.

This session will dedicate a moment to honor the contribution of François-Xavier D'Abzac to the field of fs-LA-MC-ICP-MS for stable isotopes analysis.

Secular changes in the Earth’s lithosphere are evident from the geologic record on the mineral to global scale. The nature of these changes and their relationship to Earth’s evolving tectonic system and surface environment (including atmosphere, hydrosphere, and biosphere) is an exciting area of active debate. Advances in both geochronological and geochemical analytical methods now make it possible to conduct in situ analysis on multiple complementary mineral phases within a single sample. Such information obtained on the micro scale tied to structural information (e.g., through detailed 2D or 3D maps on the thin section or hand sample scale), can offer in-depth insight on terrane evolution. Multi-scale correlation is a powerful tool enabling access to information constraining protolith/source, age, geochemical signatures and metamorphic/deformational histories from a single sample.

The power of mineral petrochronology applied to the reconstruction of global crustal processes provides the tools to answer questions such as: how have the processes that shape the Earth’s crust, including magmatism, metamorphism, and mineral reactions changed through time? When was the onset of plate tectonics, and how did the process of crust formation, deformation and recycling evolve through time? We welcome provocative ideas that offer clues towards resolving controversies of the early and modern Earth. We invite submissions with a wide range of multi scale, multi proxy approaches including, but not limited to, field to thin section observations, petrological, geochronological, and major/trace/(non-)traditional isotope geochemical studies that provide insights into geodynamics and crustal evolution processes.

Plutonic and volcanic rocks provide complementary perspectives on crustal magmatism. Plutons give direct, but time-integrated, information on the system storage conditions, internal dynamics and long-term history, while volcanic rocks provide higher resolution information about extrinsic parameters, volatile budgets and temporal changes in the eruptible portion(s) of the systems. Overall, chronological data from plutons show that crustal magma reservoirs are fed and crystallised incrementally over long time periods. They likely contain large, vertically extensive regions of rheologically stiff crystal mush that should not be readily eruptible. However, these mushes can clearly be brought to eruptible conditions, sometimes in exceptionally large quantities, by mechanisms that may not be obviously recorded in plutons. The grain-scale distribution of melt, presence or absence of fluid, and the shapes of framework-forming crystals within these mushes, will affect the mush stability and therefore influence potential eruptibility and approaches towards mobilisation. In this session, we welcome multi-disciplinary ‘crystal to crustal’ contributions to crustal magmatism, including experimental and numerical modelling approaches, perspectives on plutonic and volcanic rock records, and petrological, geochemical, textural and field observations, in order to improve our understanding of the connections, architecture, timescales and dynamics of melt-mush interaction in crustal magma systems.

Active tectonics drive dynamic changes in the crust that change our planet. The interplay between fluids and deformation has long been recognised as being important in controlling the spatial and temporal scales of tectonic behaviour. State-of-the-art geochemical and isotopic analyses of rocks, minerals, and fluids involved in these processes enable deeper insight into the coupling of geochemistry, petrology, and tectonics. We invite contributions using geochemical tools to study on a wide range of tectonic processes, from water-rock interactions associated with seismic and aseismic slip; permeability evolution and destruction; large scale volume or mass changes facilitated by active tectonics (e.g. serpentinisation); to modern-day tracing of temporal variations in geochemical systems (e.g. hot springs in tectonically active areas). 

Critical metal or critical mineral refers to the general term of a class of metal elements and their deposits that are necessary for the safe supply of high risks in today's society, mainly including rare earth, nonferrous and precious metals. These metals have unique material properties, and have irreplaceable and important uses in cutting-edge industries such as new energy, information technology, aerospace and national defense industries. In the future, the competition in international mineral resources and science and technology will largely focus on the game of controlling critical minerals. Therefore, the research on the metallogenic mechanism, effective exploration and efficient utilization theory and technology of critical minerals has risen to the national strategic level of the world's developed economies. The critical metal minerals are mainly characterized by "rare", "accompanied" and "fine". The crustal abundance of key metal elements is low, and most of them are formed together with the main ore-forming elements. They often exist in deposits in the form of adsorption, isomorphism and very fine minerals. These characteristics determine that it is difficult to understand the source transport accumulation process of key metal deposits and improve the efficient utilization level of key metal elements. Objectively, it is difficult to trace, identify and separate. Obviously, in order to achieve the goal of breakthrough in ore-forming theory, guiding ore prospecting and separation theory, it is necessary to solve the core scientific problem of the process and driving mechanism of abnormal enrichment of low abundance metal elements.

Past fluid flow within geologic structures has implications for the behavior of faults, ore mineralization, sedimentary basin evolution, subsurface microbial life, mantle-lithosphere interaction, and the exchange of matter between Earth’s fluid and solid reservoirs. Fluids lubricate and activate geologic structures, change the geochemical conditions of rock alteration, diagenesis, and metamorphism, and drive mineral dissolution and deposition. Despite their importance, paleo-fluids can be complicated to characterize; the fluids themselves are usually absent or preserved only in small inclusions, and they frequently leave incomplete or path-dependent signatures on the rocks that they affect. Many hydrogeologic systems are also subject to multiple generations of fluid flow that may partially or completely overprint one another in geochemical records. This session aims to explore the application of geochronometry, thermobarometry, biomarkers, elemental and isotopic tracers, and other geochemical tools for understanding the timing, origins, and conditions of these fluids and their impacts on the rock record. We invite abstracts focusing on geochronology, stable isotopic tracers including triple-oxygen isotopes and clumped isotope thermometry, biomarker proxies, and other geochemical approaches for probing paleo-fluids.

Past fluid flow within geologic structures has implications for the behavior of faults, ore mineralization, sedimentary basin evolution, subsurface microbial life, mantle-lithosphere interaction, and the exchange of matter between Earth’s fluid and solid reservoirs. Fluids lubricate and activate geologic structures, change the geochemical conditions of rock alteration, diagenesis, and metamorphism, and drive mineral dissolution and deposition. Despite their importance, paleo-fluids can be complicated to characterize; the fluids themselves are usually absent or preserved only in small inclusions, and they frequently leave incomplete or path-dependent signatures on the rocks that they affect. Many hydrogeologic systems are also subject to multiple generations of fluid flow that may partially or completely overprint one another in geochemical records. This session aims to explore the application of geochronometry, thermobarometry, biomarkers, elemental and isotopic tracers, and other geochemical tools for understanding the timing, origins, and conditions of these fluids and their impacts on the rock record. We invite abstracts focusing on geochronology, stable isotopic tracers including triple-oxygen isotopes and clumped isotope thermometry, biomarker proxies, and other geochemical approaches for probing paleo-fluids.

The geochemical characterization of geological fluids and their dissolved load is of great interest at the cross-roads of a variety of scientific domains, from the rheology of the crust to metal deposition. Studies are based on the analysis of both rocks that have interacted with fluids and thus that are believed to host part of the geochemical signature of the fluids and on fluids themselves thanks to analytical developments in the study of fluid inclusions. Nevertheless, geometrical and structural aspects cannot be neglected in the study of paleofluids. This session thus welcomes contributions that emphasize the importance of geological considerations (tectonics, structures, geometry) when dealing with the geochemical characterization of paleofluids. In other words, we welcome field-based geochemical studies of geological fluids on domains like rheology, mass and heat transfers, behavior of geochronological systems, and metallogeny in all geological settings and in orogenic systems of all ages.

Plutonic and volcanic rocks provide complementary perspectives on crustal magmatism, with plutons giving direct but time-integrated information on the systems dimensions, depths in the crust, internal dynamics, and long-term histories. Volcanic rocks provide higher resolution information on the temperatures, pressures, volatile budgets and melt and mineral components, as well as of temporal changes of eruptable portions of the systems. There are, though, major gaps between the two. Examples include large crustal magma bodies that exist in highly crystalline states over protracted time periods dictated by the long-term average magma fluxes, but which that can rapidly be brought to eruptible conditions, sometimes in exceptionally large quantities, owing to rejuvenation agents that are not obviously recorded in plutons. Both plutons and volcanic suites possibly show compositional changes from less to more evolved: but whether these changes happen within comparable timescales and are controlled by similar or different processes is still debated.  Spectra of ages of plutonic minerals (e.g. zircon) and mineral-scale isotope variations require plutons to be fed and crystallized incrementally, potentially from evolving magma sources, but it is unclear how increments conditioned and crystallized in supra- and sub-solidus states to result in their characteristic plutons. Are the conditions of magma flux that build plutons even the same as those that fuel volcanism? With these and many more questions in mind, we seek a breadth of “crystal-to-crustal” perspectives on plutonic and volcanic rock records to improve our understanding of the connections, dimensions, and dynamics of crustal magma systems. 

Light stable isotopes (e.g., oxygen, boron, lithium) are unique tracers of both high- and low-temperature geochemical processes and therefore have great application in igneous geochemistry. With continually improving analytical capabilities, these isotope systems are becoming more frequently applied at the scale of whole-rocks, crystals, and melt inclusions to help unravel magmatic processes and to resolve the role of crustal assimilation and fluid-assisted processes in volcano-magmatic systems. In this session, we invite submissions focusing on light stable isotope systems that: (1) contribute to our basic understanding of these systems (e.g. focusing on understanding isotopic fractionations and/or analytical techniques and standardization), (2) address scientific questions relating to how magmas evolve from their source to the surface (i.e. magma generation and differentiation), (3) aim to constrain post-magmatic processes such as low-temperature alteration. We welcome studies exploring a wide range of length-scales, from studies focusing on micron-size samples (single-crystals and their inclusions) to whole-rock sample suites to global syntheses. We particularly encourage contributions from early career researchers and those from groups that are underrepresented in the geoscience community.

Phase equilibrium modelling has become a key tool for petrologists examining the physical and chemical processes that occur during orogenesis, as evidenced by the increase in citation of the term “pseudosection” from less than 1000 in 2007 to more than 4000 in 2021 (Scopus online database). Understanding processes during orogenesis is of paramount importance for interpreting: i) the evolution of plate tectonics through time, ii) the fluxes of elements between Earth’s various reservoirs, iii) the genesis of ore deposits worldwide, and iv) the extent of fluid-rock interaction in the crust. As such, phase diagram calculations are now used to assess problems in areas of study far beyond traditional geothermobarometry and with novel applications that test the limits of what modelling can achieve.

In this session, we seek contributions that use thermodynamic modelling of petrological processes to solve geological problems at a wide range of scales. We are interested in studies that range in their application of these models from igneous to metamorphic rocks, and those that transcend these disciplinary boundaries.

Non-traditional stable isotope systems (e.g., Li, Mg, Fe, Cu, Zn, Ni, Cr, K, Si, and many others) are increasingly being used to address a wide variety of questions in metamorphic and igneous systems. However, a fundamental understanding of their behavior in different reservoirs is necessary to establish them as reliable proxies of geologic processes. The processes of assimilation, melting and crystallization, metamorphism, devolatilization, diffusion, and metasomatism can have significant, and often unconstrained, effects on their abundances, behaviors and isotopic fractionation. Yet, non-traditional isotope systems have great potential to address fundamental questions related to planetary evolution and differentiation, plate tectonics, natural hazards and geochemical cycling. This session aims to provide a forum to share the newest results on stable isotope fractionation and kinetics bridging observations from natural systems, as well as from petrological experiments. We encourage submissions from all disciplines involved in non-traditional isotope geochemistry, ranging from applied in situ and bulk isotope geochemistry, including coupled isotopic and trace element analytical work, to experimental and theoretical studies that further our understanding of non-traditional stable isotopes. Studies focused on analytical developments for new isotope systems and problematic samples, diffusion chronometry, and modeling of stable isotopic variations across different dimensions, temperatures, and timescales are also encouraged.

New advances in both geochronological and geochemical analytical methods now make it possible to conduct in situ analysis on multiple complementary mineral phases in a single sample. This can be combined with detailed 2D or 3D maps on thin section or hand sample scale, in such a way that these minerals and the information obtained from them can be tied to the structural history of the sample. This correlation on multiple scales is a powerful tool that allows us to obtain many levels of information from a single sample such as data about the protolith, crystallisation ages, geochemical variations and multiple metamorphic or deformational episodes. This level of scrutiny is vital for deciphering the complex geological histories of many rocks in order to reconstruct plate tectonic processes, and essential for improving our understanding of Precambrian geodynamics. With the history of older rocks more likely to be a collage of multiple deformation events potentially reflecting different stages in the tectonic evolution of a region.

This session invites contributions that conduct petrochronological investigations by utilising in situ techniques on complementary mineral species to investigate lithospheric-scale processes that shaped the Earth through geological time.

Crustal magma reservoirs likely comprise numerous small storage regions hosting melt-rich magma, interconnected through dykes or sills, and surrounded by large, vertically extensive regions of rheologically stiff crystal mush. The grain-scale distribution of melt, presence or absence of volatiles, and the shapes of framework-forming crystals within these mushes, will affect their stability and the ability of melt to migrate through trans-crustal magmatic systems. These factors may therefore have important consequences for the potential eruptibility of these crystal-poor mushes, and determine which processes may be effective trigger mechanisms for volcanic eruptions.

In this session, we welcome contributions on the petrology, geochemistry, physical properties, and dynamical behaviour of mushy magmatic systems. We particularly encourage contributions that help to link petrological and textural properties with experimental or numerical modelling approaches, in order to constrain the thermal and chemical architecture, dynamics and timescales of melt-mush interaction, and melt migration from mushy systems.

Secular changes in the Earth’s lithosphere are evident from the geologic record on the micro to global scale. The nature of these changes and their relationship to Earth’s evolving tectonic system and surface environment (including atmosphere, hydrosphere, and biosphere) is an exciting area of active debate. This session aims to elucidate how trends in geochemistry, often recorded in accessory minerals on the micro-scale, can inform global scale interpretations regarding geodynamics and crustal evolution. How have the processes that shape the Earth’s crust, including magmatism, metamorphism, and mineral reactions changed through time? When was the onset of plate tectonics, and how did the process of crustal formation, deformation and recycling evolve through time? We welcome provocative ideas that offer clues towards resolving controversies of the early and modern Earth. We invite submission with a wide range of approaches including, but not limited to, geochemical, petrological and geophysical studies, field observations, multi-proxy and (non-)traditional isotope studies.

Deep crustal production, storage, and transport of volatiles plays a crucial role in the chemical evolution of the Earth and global volatile budgets. Volatile cycling influences crustal rheology and partial melting, and modulates the communication between Earth’s deep interior, atmosphere, and hydrosphere. Volatile-rich crustal fluids exist within fractured and porous systems, often exhibiting at the surface as geothermal waters and springs or are accessed via wells. In addition to direct measurements from fluids and gases, volatiles can be recorded in crustal rocks. These fluids are rich in volatile species and elements (CO₂, H₂O, hydrogen, hydrocarbons, helium, nitrogen, sulphate, trace metals, halogens) sustain deep subsurface microbiome, and are important exploration targets for a variety of industrial applications (such as hydrogen and helium exploration, geological CO₂ storage, nuclear waste disposal, ore formation). They often act as tracers of planetary evolution, tectonic, magmatic and hydrological processes over deep time and space and in a variety of settings (e.g., active margins, rift zones, stable cratons, basins). This session aims to facilitate discussion amongst interdisciplinary fields focused on understanding volatiles throughout the crust, that may include the use of traditional and non-traditional geochemical tracers such as stable and clumped isotopes, noble gases, trace elements and biogeochemical tools. We welcome observational and modelling studies into the dynamics of production, release and transport of crustal volatiles, with applications to academic and industrial fields of study.

Basaltic volcanism is a major process differentiating major rocky planets, including the Earth. Despite of extensive research, many aspects of terrestrial and extraterrestrial basaltic volcanism are still hotly debated. We invite contributions using geochemical, petrological, experimental, and numerical constraints to understand both terrestrial and extraterrestrial basaltic volcanism, as well as contributions on novel analytical method development in this field.

Investigating the dynamics and timescales of magmatic processes is key to understanding the storage, emplacement, ascent, mobility and eruptibility of volcanic plumbing systems. This in turn provides insights to enable characterization of volcanic hazards and to inform governmental agencies who develop mitigation strategies. During the last few decades, our knowledge of volcanic systems has evolved such that we now know the activity of volcanoes is governed by a combination of non-linear dynamics and timescales. These are explicitly recorded in processes such as dissolution, diffusive re-equilibration in crystal mush within magma reservoirs, mineral and volatile exsolution, crystal growth morphology, and rheological transitions during magma ascent within conduits and dikes. A thorough understanding of the interplay between crystallization kinetics involving undercooling, rapid crystallization, mixing, decompression, degassing and the quantification of the timescales of these processes is fundamental to understand and model non-linear and complex physico-chemical processes.

In this session, we aim to bring together studies that investigate the dynamic nature of magmatic processes both in the laboratory and in nature, and we welcome multidisciplinary contributions from mineralogy, petrology, geochemistry and numerical modelling, to further our understanding of magma dynamics, development and evolution of plumbing systems.

Textural and compositional variations in plutonic and volcanic rocks depend on mantle source heterogeneities and translithospheric processes (e.g., magma mixing, crystallization, and melt-crystal interactions within mushes and magma reservoirs connected through a network of dykes and sills). Mantle heterogeneities are in part responsible for the diversity of primitive melts, ranging from tholeiitic basalts to alkaline melts and ultrapotassic melts such as lamproites, however their compositions, melting characteristics, and evolution require further investigation. Translithospheric processing depends on magma ascent rates, which determine the potential for interaction between magmas and wall rocks of the plumbing system, together with the thermal structure of the lithosphere, which governs crystallization behaviour and concomitant evolution of melt, fluid and gas exsolution from magmas, and brittle versus ductile crustal responses to magma ascent. Further, an understanding of the processes leading to the geochemical and petrological diversification of magmas are a prerequisite for the development of appropriate and effective volcano monitoring strategies.

We invite contributions from a wide range of disciplines across all tectonic settings, including:

• experimental petrology, providing the PTtX-context for observations of natural samples
• analytical petrology and geochemistry, including isotopic investigations and thermobarometric/geospeedometric studies of intrusive and eruptive products
• exploration of the origin and evolution of the volatile phases, including carbon, water, and the halogens (e.g., through the study of melt inclusions)
• thermodynamic, numerical, and computational modelling
• geophysics to inform the interpretation of data provided by other disciplines
• physical volcanology to elucidate links between subvolcanic processes and eruptive activity

NOTE: This live event includes sessions 5cO3 and 2fO1, in that order, with no break between them.

Recent years have seen eruptions from well monitored and accessible volcanoes including Kīlauea (HI, USA), Fagradalsfjall (Iceland), Cumbre Vieja (La Palma, Canary Islands), Mount Etna (Italy) amongst others. Frequent sampling over the course of an eruption contributes unique temporal information to petrological and geochemical datasets that complement traditional, continuous monitoring approaches. Such sampling produces large amounts of petrological or geochemical data that yield unusually deep insights into individual eruptive events. Moreover, frequent sampling increasingly allows observations from petrology and geochemistry to be meaningfully integrated with observations from remote sensing, ground deformation, and seismicity. Many volcanoes are tourist attractions or are proximal to urban centers and thus understanding the temporal evolution of eruptions and anticipating shifts in eruption style and intensity remains an important challenge that petrological and geochemical monitoring can help address. Changes in the texture and chemistry of volcanic eruption products may provide unique information on how magma sources and characteristics shift through time and reinforce observations from other monitoring strategies. We encourage submissions that include high temporal resolution petrological or geochemical datasets, interdisciplinary volcano monitoring and study efforts, or other detailed or unique perspectives on recent volcanic eruptions. Of particular interest are works on aspects such as in depth understanding of the deeper magmatic and the near surface volcanic systems, as well as on the mechanisms and controls of eruptive processes. Works on the impacts of recent eruptions on the surface environment and the atmosphere in a local and regional context are also welcome.

Volatiles and fluids play a crucial role in magmatic processes occurring in between the Earth’s mantle and surface. The past decades have witnessed substantial developments in the measurement of volatile species (C, O, H, S, halogens, noble gases) and their respective isotopes in minerals, fluid/melt inclusions, and/or gaseous emissions, providing key information for investigating melt extraction and metasomatism in the mantle, magma ascent and degassing, volcanic unrest, mineral deposit formation, and the impact of the long-term volatile cycling on climate change. Yet, key characteristics and properties of fluids, melts, and volatiles still need to be investigated to link the surface observations to the processes occurring at depth and thus develop comprehensive models of the chemical exchanges between lithosphere, biosphere and atmosphere.

This session aims at bringing together scientists from a broad range of disciplines to discuss the influence of volatiles and fluids on the short to long-term processes at the crust-mantle scale. We welcome contributions based on but not limited to field observation, geochemical analysis, experimental petrology, and numerical models. We particularly invite discussion on (i) petrological records of volatiles and fluids (e.g. in melt/fluid inclusions, and minerals such as apatite), (ii) volcanic gas emissions and their link to volatiles originated from depths, (iii) volatile behaviour in multicomponent mineral-fluid-melt systems and their influence on trace element and metal partitioning, and (iv) the establishment and applications of novel analytical techniques, computational models, and interdisciplinary approaches to study these enigmatic phases.

The record of Large Igneous Provinces (LIPs) is continually expanding back in time and now includes events older than 3 Ga. Associated with this expanding LIP record, there is now an increased understanding of LIP plumbing systems and origin (typically associated with mantle plumes). LIPs are now recognized to have played a key role in major geodynamic processes, including formation and evolution of the lithosphere, and supercontinent breakup. These important phenomena also frequently coincide with complex environmental changes, including mass extinctions, oceanic anoxic events, hyperthermal events, global glaciations, regional topographic changes, ore deposit formation, and significant silicic magmatism (SLIPs), carbonatites and kimberlites. We welcome contributions from a diverse range of disciplines to encourage cross-fertilization of ideas and a multi-faceted discussion of LIP systems, including igneous and sedimentary geochemistry, experimental petrology, geochronology, and studies utilising chemical and biological proxies in the stratigraphic record. Novel and provocative contributions are particularly encouraged, as well as those from groups underrepresented in the geoscience community.

Transcrustal magmatic systems host plutonic rocks, crystal mushes, and magma reservoirs, connected through a network of dykes and sills. These systems can also extend into the lithospheric mantle. System architecture and thermal structure are critical parameters for understanding the genetic history of intrusive magmatism and the style of volcanic eruptions, as well as textural and compositional variations in eruptive products. Understanding the architecture and construction of translithospheric magmatic systems is therefore a prerequisite for understanding and mitigating volcanic hazards through the development of appropriate and effective volcano monitoring strategies. Further, the thermal structure of these translithospheric magmatic systems governs crystallization behaviour and concomitant evolution of melt, fluid and gas exsolution from ascending magmas, brittle versus ductile crustal responses to this ascent, and the depth and extent of formation of economic mineral deposits.

We invite contributions from a wide range of disciplines that may shed light on these topics across all tectonic settings, including but not limited to:

• experimental petrology, providing the PTtX-context for observations of natural samples
• analytical petrology and geochemistry, including thermobarometric and geospeedometric studies of intrusive and eruptive products, encompassing the volatile phases (e.g., hygrometry, melt and fluid inclusion analysis)
• physical volcanology to elucidate links between subvolcanic processes and eruptive activity
• thermodynamic and numerical modelling
• economic geology
• geophysics to inform the interpretation of data provided by other disciplines

We particularly encourage studies that combine diverse approaches and demonstrate that collaborative efforts can provide new insights that escape detection by individual disciplines.

The role of magmatic fluids in geological processes and their impact on human society is now indisputable: they are critical agents that facilitate the chemical exchanges between the Deep Earth, crust, hydrosphere and atmosphere; their release may affect the rheology and eruptivity of magmas; and finally, they are key to the formation of many types of ore deposits.

Yet, key characteristics of their early history such as the relative significance of decompression versus crystallization-driven degassing and the fluid/melt partitioning of elements over a broad pressure-temperature-composition range, as well as and the evolution of their composition and properties during cooling, decompression and fluid-rock interaction remain poorly understood. And so do the physical mechanisms of their extraction from magmas.

The aim of this session is to bring together all existing forces to discuss: 1) How we can track magmatic fluids through the petrological record (e.g., mineralogical/geochemical tracers, fluid and melt inclusions); 2) How we can investigate their physico-chemical properties in the experimental laboratory; and ultimately 3) How we can develop new geochemical models or improve existing ones to simulate magma degassing and fluid-rock interaction under high-pressure-temperature conditions.

There is an ongoing dramatic expansion of the global Large Igneous Provinces (LIP) record back to >3 Ga, and progress in characterizing the LIP plumbing system and link with mantle plumes, and understanding the key role that LIPs have in a range of major geodynamic processes, including formation and evolution of lithosphere and mantle, supercontinent breakup, dramatic climate change including mass extinctions, major regional topographic changes, formation of major ore deposits, and links with silicic magmatism (SLIPs), carbonatites and kimberlites. This session welcomes presentations on all aspects of these many exciting frontier research areas on LIPs.

There is an ongoing expansion of the global Large Igneous Provinces (LIPs) record back to >3 Ga, and an increasing understanding of the LIP plumbing system and origin (typically mantle plumes). LIPs are recognized to have key role in a range of major geodynamic processes, including formation and evolution of the lithosphere and mantle, and supercontinent breakup. Moreover, LIPs frequently coincide with complex environmental changes, including mass extinctions, oceanic anoxic events, and hyperthermal events, major regional topographic changes, formation of major ore deposits, and have links with silicic magmatism (SLIPs), carbonatites and kimberlites. We invite submissions to a cross-disciplinary session from researchers working in all these exciting frontier research areas on LIPs.

Large Igneous Provinces (LIPs) were exceptional magmatic events that involved massive exchanges of energy and matter between the mantle and the shallower Earth reservoirs – crust, hydrosphere and atmosphere. As such, they played a pivotal role in shaping past climates and the biosphere and ultimately in driving Earth habitability to and beyond tipping points. Intriguingly, different LIP events could have led to very different responses and feedbacks in the Earth system, from hyperthermals to Snowball-Earth, from selective or widespread extinctions to radiations in biotic diversity. Determining the reasons why LIPs were seemingly such versatile drivers of global change is a highly active and debated field of current geoscientific research. This session aims at showcasing recent findings about the nature of LIPs, from their origin and evolution as complex magmatic entities, to the mechanisms through which the Earth system responded to their emplacement, e.g. how the atmo- hydro- and biospheres were affected by volatile release via magmatic and/or contact metamorphic degassing. We welcome contributions from a diverse range of disciplines to encourage cross-fertilization of ideas and a multi-faceted discussion of LIP systems, including igneous and sedimentary geochemistry, experimental petrology, geochronology, and studies utilising chemical and biological proxies in the stratigraphic record. Novel and provocative contributions are particularly encouraged, as well as those from groups underrepresented in the geoscience community.

Recent years have seen eruptions from well monitored and accessible volcanoes including Kīlauea (HI, USA), Fagradalsfjall (Iceland), Cumbre Vieja (La Palma, Canary Islands), Mount Etna (Italy) amongst others. Frequent sampling over the course of an eruption contributes unique temporal information to petrological and geochemical datasets that complement traditional, continuous monitoring approaches. Such sampling produces large amounts of petrological or geochemical data that yield unusually deep insights into individual eruptive events. Moreover, frequent sampling increasingly allows observations from petrology and geochemistry to be meaningfully integrated with observations from remote sensing, ground deformation, and seismicity. Many volcanoes are tourist attractions proximal to urban centers and thus understanding the temporal evolution of eruptions and anticipating shifts in eruption style and intensity remains an important challenge in volcanology that petrological and geochemical monitoring can help address. Changes in the texture and chemistry of volcanic eruption products may provide unique information on how magma sources shift through time, reinforce observations from other monitoring strategies and indeed provide clues about when eruptions may be terminate. We encourage submissions that include high temporal resolution petrological or geochemical datasets, interdisciplinary volcano monitoring efforts, or other detailed or unique perspectives on volcanic eruptions

Intraplate continental volcanism is expressed by a huge and unusual geochemical diversity of primitive melts, spanning tholeiitic basalts to alkaline melts and ultrapotassic melts such as lamproites. This huge geochemical diversity, trace element concentrations and isotopic signatures do not reflect a homogenous single mantle source, and must therefore be explained by mantle heterogeneities or mixing of magmas derived from distinct mantle sources. The role of recycled volatiles components, including carbon, water, and the halogens may be essential in generating these distinct sources. However, what these mantle sources are is still enigmatic, and it remains unclear what kind of flavours of melts these would produce. In addition to their complex mantle sources, the geodynamic causes of intraplate magmatism are often challenging to interpret without clear evidence for cause such as plume interactions or active rifting.

To begin addressing these crucial gaps in our knowledge we welcome all contributions from those working on determining the mantle sources of continental melts, especially those with an interest in continental alkaline volcanism. All approaches are welcome including but not limited to high-pressure experiments, analysis and petrology of melts and crystals, melt inclusion studies, geophysical surveys and computations, and other novel techniques.

Linking the surface gaseous emissions in active volcano-tectonic areas to the processes occurring at depth in the lithosphere is crucial to model the long-term volatile cycle, the short-term variations associated with volcanic and seismic unrest, and ultimately the impact of crust- and mantle-derived degassing on climate change. The measurement of volatile species (C, O, H, S, halogens, noble gases) in magmatic and metamorphic minerals, fluid or melt inclusions and gaseous emissions helps constrain: i) the storage and migration of fluids throughout the lithosphere and their role during melt extraction and metasomatism; ii) the impact of degassing on magma ascent and the evolution of plumbing systems beneath active volcanoes; iii) the shallow processes (e.g., assimilation-fractional crystallisation) that may act as triggers of volcanic unrest; iv) the mobilization of metals associated with the formation of mineral deposits; and v) the role played by the crust in surface degassing. This session is aimed at exploring and discussing all aspects of the storage, migration and emission of volatile species at the crust-mantle scale, and their relationships to the long- or short-term processes shaping the surface of our planet, including their socio-economic impacts. It will embrace contributions from a broad range of disciplines, including gas and rock geochemistry, magmatic and metamorphic petrology, ore geology, experimental petrology and thermodynamics, and volcano and seismic monitoring.

After several years of seismic unrest, a volcanic eruption started at La Palma Island on the 19^th of September 2021, representing the first subaerial eruption in the Canary Islands in 50 years. During the 85 days of the eruption, combined explosive and effusive activity resulted in the emission of vast amounts of pyroclastic materials, lava flows, and gases, which had a huge impact on the landscape, environment, infrastructure and populations of the island. Thanks to pre- and syn-eruptive monitoring, the growth and evolution of the resulting volcano could be observed from the very beginning. In addition, easy road access to the area allowed detailed observations on the eruption and continuous sampling of emitted products. As a result, the 2021 La Palma eruption is like no other in terms of the amount of scientists and institutions involved in its monitoring and scientific study, and has clearly become one of the best recorded and sampled to date.

This session aims to provide a multidisciplinary platform to present the different facets of geochemical research currently being carried out on the La Palma eruption, with particular emphasis on the mechanisms, controls, impacts and consequences of the La Palma eruption. Important aspects such as in depth understanding of the deeper magmatic and the near surface volcanic systems are especially welcome, as is research on eruptive processes, and the impacts of the eruption on the surface environment and the atmosphere in a local as a well as in a regional context.

Volatiles control a variety of physical and chemical properties of magmas and thus play a key role in magmatic processes that occur from the Earth’s mantle to the surface. Volcanoes and their eruption products (such as rocks, minerals, and gases) provide us with an excellent opportunity to cracking the code of volatile behaviour before/during eruptions, and their influence on pre-eruptive magma recharge, storage, migration, eruption size and explosivity, and the formation of hydrothermal ore deposits. The past few decades have witnessed substantial developments, from theoretical, analytical, and computational aspects, on several petrological and geochemical methods applicable to studying magmatic volatiles and their respective isotopes, from classic melt inclusion studies to the analysis of volatile-bearing minerals such as apatite.

This session aims to bring together scientists from a broad range of scientific backgrounds to enhance our understanding of magmatic volatiles (elements/ isotopes), and the roles that they play in arc magmatism and volatile cycling, volcanic eruption styles, and ore formation. We welcome contributions based on methods including but not limited to field observation, geochemical analysis, experimental petrology, and numerical models. We particularly invite discussion on magmatic volatile budgets, volatile partitioning between mineral-fluids-melts, volcanic gas emission and links to pre-eruptive volatiles, hydrothermal ore formation, and the establishment and applications of novel analytical techniques, computational models, and interdisciplinary approaches.

Large igneous provinces (LIPs) eruptions frequently coincide with complex environmental changes, including mass extinctions, oceanic anoxic events, and hyperthermal events. Over the past decade, geochemical indicators of LIP activity in sedimentary records, such as sedimentary mercury, have been increasingly used to constrain the timing of LIP activity at high resolution and assess the causal relationship with a wide range of environmental change events.

These LIP proxy records present great opportunity, as they are directly comparable to other paleoclimate records from the same locations with no uncertainty in relative chronology. However, as our use of the mercury proxy has increased, so too has our understanding of various non-volcanic factors which can influence the interpretation of these records, such as varying lithologies and sedimentary host phases, local vs. global distribution of mercury, and various types of diagenetic alteration.

We invite submissions to a cross-disciplinary session from researchers working on any aspect of LIPs and associated environmental change events, but especially work which uses and advances our understanding of sedimentary proxies of LIP activity from both data and modeling perspectives. This may include, but is not limited to, sedimentary mercury, sulfur, nickel, chromium, and osmium concentrations and isotopic compositions.

In surface water, soil and atmosphere, complex (bio)geochemical processes control the fate and transport of elements and nanoparticles shaping natural geochemical environments. The reactivity of materials in such systems can be attributed to the interfacial chemistry involving the composition and structure of the (nano)material itself but also to the nature of the surrounding environment. The understanding of the mechanisms controlling geochemistry at the solid-water interface such as mineral (trans)formation pathways, ion adsorption-desorption rates and mechanisms, interfacial redox reactions and effect of organic matter on surface reactivity is a major challenge for scientists to achieve. 

To better understand the phenomena and behaviour that underpin bulk-scale observations, novel analytical methods question the representativeness of samples, their preparation artefacts and biases, the optimization of analysis conditions, the capacity to process large volumes of data, and the relation of the outcomes to their functioning and impact in natural systems. In addition, modern microscopies performing imaging in situ comprise a wide range of new instrument and software developments with numerous applications in environmental sciences, using scanning probes, electrons and photons from infrared to X-rays. They are often used together with integrated spectroscopy techniques, combining knowledge of the morphology, chemical composition, and state of materials down to the nanometer scale in native environments. Together with theoretical and computational approaches and the implementation of machine learning tools, these experimental methods have enabled the analysis of large sets of reactivities at the solid-water interface. This includes work that explores the natural nanogeochemical environment using new tools and techniques, as well as work that addresses analytical challenges at the frontiers of nanogeochemistry, including experimental studies, modeling, theory, and perspectives.

The measurement of nanoparticle properties facilitates new understanding of processes and dynamics in the natural nanogeochemical environment.  At the same time, new challenges have arisen for both analysis and understanding: the range of available techniques and massive volumes of data open new windows to better understand the phenomena and behaviour that underpin bulk-scale observations, but also generate new questions that span disciplines and emerge at all stages of scientific investigation. Examples of such questions include: representativeness of samples; artefacts from sample storage/treatment; biases associated with sample introduction; optimizing analysis conditions and LOD determination; techniques and computational capacity to pre-process/winnow large volumes of multidimensional data; techniques and computational capacity to sort/classify/integrate the data in environmentally-relevant ways, and; relating the outcomes of such analyses at the nanoscale to their functioning and impact in natural systems containing millions or billions of particles in a few liters of water or air.  This session welcomes submissions that explore the natural nanogeochemical environment using new tools and techniques, as well as work that addresses analytical challenges at the frontiers of nanogeochemistry, including experimental studies, modeling, theory, and perspectives.

Reactions forming, consuming, and transforming solid materials, especially at the nanoscale, often proceed through a series of intermediates forming a dense energy landscape of possible structures and pathways. This landscape determines both the thermodynamically accessible metastable states and the barriers between them, determining which minerals can and cannot be observed during biomineral formation, in geochemical processes including redox reactions, isotopic fractionation, hydrothermal transport and deposition, phase transformations in the deep Earth, microbial biofilm deposition, sedimentation and diagenesis, weathering, fossilization, in engineered systems including disposal of nuclear waste in geological repositories and CO₂ sequestration and H₂ storage in underground formations, as well as the synthesis and degradation of and catalysis by synthetic and technologically important materials. Energy landscapes and structure at the molecular, nanoscopic, mesoscopic and macroscopic scales provide a complete description of all these systems, yet only a handful of them have been characterized thoroughly, including both experimental and theoretical approaches. This session aims to bring together participants from the biomineralization, geochemistry, mineralogy and materials community to explore the common features of energy landscapes and transformations in complex systems, including, but not limited to, carbonates, phosphates, transition metal oxides, silica, silicates, and porous materials. The roles of interaction at surfaces and interfaces, also involving organic molecules ranging from simple molecules to proteins and polysaccharides, will be welcomed.

The advent of a new technology commonly leads to major advances in science. The new generation of tandem mass spectrometers (single and multicollector ICP-MS/MS) provides the geochemical community with a wealth of new isotopes systems and a rejuvenation of old favourites, such as ⁸⁷Rb-⁸⁷Sr, to investigate our world. The ability to use reaction gases to either remove isobaric interferences or to form molecules with the element of interest and thus move to a mass away from interferences provides the potential for increased precision and increased utility of many stable and radiogenic isotope systems.

New technology naturally comes with new hurdles to overcome. These include, but are not limited to, a lack of matrix-matched reference materials, new challenges for downhole fractionation corrections, and additional considerations for mass bias corrections and pulse/analog factors.

In this session we invite contributions on the development of techniques, reference materials, data reduction, novel reaction cell gases, and other studies related to reaction cell tandem mass spectrometry. We hope to bring together many different element and isotope systems, and also applications of tandem mass spectrometry to different fields, including but not limited to geology, geochronology, nuclear forensics, and biogeochemistry.

With its unmatched mass resolving power and mass accuracy, Fourier transform mass spectrometry (FTMS; e.g. FT-ICR, Orbitrap) is becoming an extremely valuable tool for environmental chemists and biogeochemists. If petroleum analysis was historically the driving force behind its development, FTMS has now found a wealth of applications in the characterization of complex mixtures of geochemical, biogenic and anthropogenic origins in the geosphere.

FTMS opened the door to nontargeted, molecular-level identification of organic and organometallic compounds and the elucidation of their abiotic and biological transformations in virtually all environmental matrices from atmospheric, aquatic (freshwater and marine), terrestrial and extraterrestrial compartments.

Combined with the recent developments in advanced bioinformatic methods of visual representation of complex mass spectral features and the implementation of machine learning tools, FTMS analysis allows the discovery of information hidden in biogeochemical data, improving our comprehension of the Earth system.

This session invites researchers with a broad range of expertise interested in FTMS approaches to address fundamental biogeochemical questions about chemical, physical, hydrologic and microbial interactions that affect the transformation and mobility of critical nutrients, contaminants, aerosols and particles.

We seek contributions that:

• cover new methodologies and applications of FTMS,
• showcase new techniques of data processing of often very complex FTMS datasets and
• develop best practices to enable biogeochemical data to be shared, integrated and repurposed to meet emerging biogeochemical challenges.

Laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) is a well-established technique for in-situ isotope analyses of minerals and glasses. The widespread use of nanosecond lasers as well as the emerging ultrafast femtosecond (fs) lasers coupled to a MC-ICP-MS have led to a better understanding of the processes involved in stable isotope fractionation at the mineral scale (e.g., in zircon, olivine, pyroxene, plagioclase, magnetite, etc). Recently, new in-situ measurement protocols were developed in order to resolve small variations in non-traditional stable isotope composition of igneous minerals (e.g., for Fe, Si, Mg, Zr, Li.). These measurements yield isotope compositions of high reproducibility, high accuracy and, more importantly, high spatial resolution, which allow scientists great insight into magmatic and other high-temperature processes.

This session honors the contribution of François-Xavier D’Abzac to the field of (fs)-LA-MC-ICP-MS. Therefore, we invite contributions related to the development of new methods for in-situ stable isotope analyses using LA-MC-ICP-MS, as well as new applications of well-established protocols that enable a better understanding of high-temperature processes (e.g., magmatic differentiation, crustal recycling, mantle heterogeneities, kinetic processes, diffusion, ore formation, impact events, meteorite formation). Additionally, we strongly encourage submissions of young/early career scientists and those from traditionally under-represented groups.

Geochemical systems and geomaterials exhibit a great variety of complex behaviors, possible structures, and patterns in their spatial and temporal organization. Some mechanistic analogues to living organisms or biological systems can be drawn based upon the concept of dissipative systems developed by the Nobel prize laurate Ilya Prigogine to describe thermodynamically open systems out of equilibrium. Since this kind of systems are ubiquitous geochemical systems, the phenomena of self-organization, complexity reduction, and synergetic effects of interactions between different system components should be common as well. For example, according to recent studies, the self-organized behavior of pre-biotic silica and other minerals were likely to arrange settings for organic life emergence.

In this session we aim at new epistemological discoveries in geochemistry of complex natural and man-made systems, and geomaterials, with the focus on their self-organization, self-assembly, aggregation, phase transformations, growth, dissolution, adsorption, and material transport. We call for abstracts shedding light onto mechanisms and driving forces of geochemical pattern organization and non-equilibrium behavior. Examples include but not limited to mineral surfaces out of equilibrium, mesocrystals and hierarchical geomaterials, formation of oscillatory zoning and solid solutions, aggregation, phase transitions, biomineral growth, irreversible and non-equilibrium thermodynamics, solid-fluid systems at confined pore spaces, transport networks in georeservoirs, pre-biotic inorganic systems related to the origin of life, fractal models, etc. We welcome any contribution of any kind, experimental, modelling, simulation, theoretical or conceptual endeavor in understanding complex system behavior at the fundamental level. Unexplained novel patterns, structures, and system behaviors are welcomed as well.

New molecular and isotopic techniques have recently opened multiple research avenues. Non targeted, molecular-level identification of complex organic and organometallic mixtures allow discussing their abiotic and biological transformations in virtually all environmental matrices from atmospheric, aquatic (freshwater and marine), terrestrial and extraterrestrial compartments. Measurements of simply and doubly substituted isotopologues of various molecules (CH4, H2, N2, O2, and others) as well as position specific isotope ratios allow for the quantitative reconstructions of modern and past biogeochemical cycles.

This session invites researchers with a broad range of expertise interested in both novel molecular and light stable isotopes approaches to address fundamental (bio)geochemical questions about:
(i) chemical, physical, hydrologic and microbial interactions that affect the transformation and mobility of critical nutrients, contaminants, aerosols and particles
(ii) the emerging fields of light stable isotopes focused specifically on multiply substituted isotopologues and position specific isotope determinations

We seek contributions that:

- cover new methodologies and applications of molecular fingerprinting and light stable isotopes
- showcase new techniques of data processing of often very complex datasets and
- develop best practices to enable biogeochemical data to be shared, integrated and repurposed to meet emerging biogeochemical challenges.

Stable isotopes are critical tools in earth & planetary sciences for the quantitative study of biogeochemical cycles both extant and ancient. For example, isotopic measurements can allow for the establishment of whether or not a molecule was synthesized or interacted with living organisms and allow for quantitative reconstructions of past biogeochemical cycles. Accurate reconstructions past biological signatures or geochemical processes based on the stable isotopic composition of earth materials requires an understanding for the mechanics of how processes fractionate isotopes, and where relevant, preserved. This session seeks to bring together individuals working on a variety of topics in the emerging fields of light stable isotopes focused specifically on multiply substituted isotopologues and position specific isotope determinations. Examples of isotope systems and systematics we encourage (but are not limited to) include clumping in hydrogen, methane, nitrogen, oxygen or other small gaseous molecules, as well as position specific work in more complex organic molecules.

We encourage submissions that will aid in the dialogue between groups working on modern, experimental, abiotic or biological isotopic signatures, with those working to use these systems to interpret large-scale processes on Earth today or in the past.

This live event includes sessions 14cO2 and 6gO2, in that order, with no break between them.

Reactions at mineral-fluid interfaces such as ion sorption, dissolution, nucleation and crystal growth are often studied and modeled at the nanoscale using mineral surface structures and solution phase organization determined at equilibrium or near-equilibrium conditions. However, the validity of these simplifications decreases as we move away from mild reaction conditions to those that more adequately represent the structure and free energy landscape during reactions far from equilibrium or under extreme conditions. Examples where typical assumptions may break down include reactions in: (i) viscous concentrated solutions, slurries, and melts; (ii) fluids under nanoconfinement such as in clay interlayers, nanotubes, and ion channels within biological membranes; (iii) systems under ionizing radiation such as that typically found in radioactive waste; (iv) systems subjected to high temperature, pressure, or rapid changes in conditions.  Understanding reaction mechanisms at the molecular scale in such systems remains a challenge for current theories and methods.

We welcome contributions exploring geochemical systems at the nanoscale that seek to address interfacial reaction mechanisms that encompass the added complexity of far-from-equilibrium or extreme conditions. We particularly invite those using innovative experimental methods, or those developing new approaches to interrogate experimental data with computational chemistry.

The mobilization of hazardous metal(loid)s and radionuclides from natural and anthropogenic sources such as mine tailings, battery residues, and radioactive wastes leads to contamination of the natural environment. Understanding (bio)geochemical processes (e.g., (trans)formation, sorption, and redox reactions) between chemical elements and geomaterials is essential for assessing the fate of contaminants into the environment and predicting their environmental and health impacts. Synchrotron X-ray scattering and spectroscopic techniques have contributed to  the geochemistry by unveiling mechanistic processes of Earth-relevant materials through the observation and visualization of the chemical and structural properties from atomic to microscopic scales. These capabilities have been vastly enhanced by the emergence of the new 4^th generation source of X-rays with higher brilliance and coherence. This session seeks original research on the geochemical behaviors of inorganic and organic contaminants using state-of-the-art synchrotron techniques and analyses, highlighting advances in novel synchrotron methods and new opportunities that upgraded photon sources bring together to the geochemistry community and other scientific disciplines.

Topics of interest include, but are not limited to:

• In-situ observation of pore- to molecular-scale reactions at liquid–solid interfaces
• High-resolution visualization of chemical and structural complexities of materials
• Rare earth element X-ray spectroscopy
• Reaction kinetics and dynamics in geochemical systems
• Metalloids and radionuclides behavior in natural and anthropogenic systems
• Development of new synchrotron techniques and algorithms
• X-ray data analysis with artificial intelligence

In surface water, soil and atmosphere, complex (bio)geochemical processes control the fate and transport of elements shaping our climate and sustaining life. The reactivity of materials in such environmental systems can be attributed to the interfacial chemistry involving the composition and structure of the material itself but also to the nature of the surrounding environment. The understanding of the mechanisms controlling (bio)geochemical cycles at the solid-water interface such as mineral (trans)formation pathways, ion adsorption-desorption rates and mechanisms, interfacial redox reactions and effect of organic matter on surface reactivity requires a deep understanding of the solid-water interface in its native conditions.

Development of large-scale geochemical models requires understanding of key atom- to nano-scale processes, from mineral formation and dissolution to ion exchange, redox reactions, transport and adsorption at mineral surfaces. High-resolution experimental and computational research can characterise ubiquitous metastable and inherently disordered intermediates during adsorption, transport, mineral nucleation and growth. Similarly, defect structures strongly influence ion exchange, transport, adsorption, surface reactivity and mineral growth in both geological and biogenic minerals. Novel experimental and theoretical approaches will develop new geochemical concepts to determine the structure, stability, and geochemical significance of disordered phases, defect structures and mineral interfaces over multiple length and timescales.

This session seeks contributions from both experimental and computational disciplines that can advance the current effort to characterize the formation, structure and reactivity of (bio)minerals and mineral interfaces. We invite contributions that present novel syntheses, characterization approaches, computational methods, or modeling approaches that advance our understanding of fundamental geochemical processes. Topics of interest include, but are not limited to mineral nucleation and growth, pollutants and contaminants adsorption and transport at mineral interfaces, reactivity at mineral interfaces, structural characterization of dopants/impurities, defect structures, amorphous and metastable intermediates in mineral and biomineral formation and bio-inspired mineralization processes.

This session is dedicated to analytical methods, instrumentation and reference materials used for the development, calibration, and interpretation of stable/radiogenic isotopic and/or elemental measurements in cosmochemistry, climate science, nuclear non-proliferation, geochronology and thermochronology, igneous and metamorphic petrology, detrital mineral provenance, lithosphere – hydrosphere evolution and environmental change, biology, geophysics, and/or big data science. The emphasis is on the presentation and discussion of the analytical protocols, both procedural and instrumental, used to make challenging measurements for characterization of materials in the solid state, or as aqueous, molecular, or gas phases. Reference materials may include natural or synthetic mineral, glass or pressed powder solids, or synthetic isotopic tracer spike solutions. Presentations that introduce and characterize new reference materials or give new or revised reference values and homogeneity data for reference materials already in use are both welcome. Discussion of instrumental parameters for measurements, method validation and quantification of accuracy and precision using reference materials, and determination of the uncertainty budget of methods are relevant. We particularly solicit contributions that demonstrate the state of the art in detection limits, precision and/or small, micro- to nano-scale analytical volumes or present a roadmap to advance to the next level of material characterization. For big data applications, where very large numbers of analyses are made over weeks to months, studies documenting long-term reproducibility are important. The interdisciplinary nature of this session is meant to stimulate cross pollination of methodologies and application spaces.

This session is sponsored by:

• The development of computational capacity and data science tools such as machine learning (ML) and other mathematical algorithms are essential to planetary data-driven research. First, these tools can be used to study the large amount of observational and experimental geochemical data (covering the atmosphere, hydrosphere, solid Earth, and planetary bodies) that has been collected and accumulated over time. With the development of advanced computational methodologies, information previously hidden in these data can be revealed to enhance our understanding of the mechanism driving the Earth system. Second, data science and ML techniques are becoming crucial for future planetary missions. These missions will be equipped with next-generation instruments capable of producing vastly more data than can be sent back to Earth, while facing severe transmission limitations (e.g., communication delays, limited bandwidth, harsh environment, etc.). The ability to autonomously detect signals of scientific interest onboard using data science and ML techniques could enable data prioritization to increase mission science return from outer solar system targets.
   
  This session invites submissions from all relevant research areas (e.g., planetary science, analytical chemistry, field or laboratory geochemistry, geobiology, computer science), with the purpose of sharing research ideas and current developments of consistent methods, aiming at investigating a broad range of planetary data to elucidate the unresolved mysteries of Earth, environmental and planetary science, as well as discussions about methods development, data quality and trustworthiness. The session further calls for discussions about onboard software and potential more autonomous flight instruments for the analysis of data from planetary missions.

In surface environments, complex (bio)geochemical and physical processes control the mobility and bioavailability of elements from nanoscale to global scales. The reactivity of materials in such environmental systems can be attributed to the chemical composition and structure of the material itself but also to the nature of the surrounding environment. The understanding of the mechanisms controlling (bio)geochemical cycles such as mineral (trans)formation pathways and reactivity requires a deep understanding of the mineral in their native environments, which is a major challenge for scientists to achieve. Modern microscopies performing imaging in situ comprise a wide range of new instrument and software developments with numerous applications in environmental and geosciences, using scanning probes, electrons and photons from infrared to X-rays. They are often used together with integrated spectroscopy techniques, combining knowledge of the morphology, chemical composition, and state of materials down to the nanometer scale in native environments. These new instruments and techniques have expanded the ability to study geochemical reactivities down to the nanoscale. Together with theoretical and computational approaches and the implementation of machine learning tools, these experimental methods have enabled the analysis of large sets of in situ reactivities at the nanoscale, the extraction of key spatial-temporal parameters, and the improvement of parameter sets for molecular dynamics simulations. The aim of this session is to bring together scientists using experimental, theoretical, and computational approaches to unravel geochemical processes and foster discussion on how these new approaches may improve our understanding of chemical processes across scales in Earth surface systems.

In surface environments, complex (bio)geochemical and physical processes control the mobility and bioavailability of elements from nanoscale to global scales. The reactivity of materials in such environmental systems can be attributed to the chemical composition and structure of the material itself but also to the nature of the surrounding environment. The understanding of the mechanisms controlling (bio)geochemical cycles such as mineral (trans)formation pathways and reactivity requires a deep understanding of the mineral in their native environments, which is a major challenge for scientists to achieve. Modern microscopies performing imaging in situ comprise a wide range of new instrument and software developments with numerous applications in environmental and geosciences, using scanning probes, electrons and photons from infrared to X-rays. They are often used together with integrated spectroscopy techniques, combining knowledge of the morphology, chemical composition, and state of materials down to the nanometer scale in native environments. These new instruments and techniques have expanded the ability to study geochemical reactivities down to the nanoscale. Together with theoretical and computational approaches and the implementation of machine learning tools, these experimental methods have enabled the analysis of large sets of in situ reactivities at the nanoscale, the extraction of key spatial-temporal parameters, and the improvement of parameter sets for molecular dynamics simulations. The aim of this session is to bring together scientists using experimental, theoretical, and computational approaches to unravel geochemical processes and foster discussion on how these new approaches may improve our understanding of chemical processes across scales in Earth surface systems.

Full understanding of geochemical events at the smallest scales would mean achieving characterization from the atom-scale to the nanoscale. Key geochemical processes and phenomena – such as ion exchange and transport, redox reactions, adsorption – occur at complex geochemical interfaces, interlayers and within the pore space. These can be rationalized in terms of the surface structure and geometry, composition and reactivity. Improved knowledge of those processes will develop new geochemical concepts and further technological applications of interfaces in solid and porous media. In this session, we bring together researchers in computational and analytical methodologies that can unravel geochemical interfaces at the smallest scales. All applications to pollutants and contaminants transport and remediation, carbon sequestration, construction, mineral formation and of course geochemistry are welcome.

Full understanding of geochemical events at the smallest scales would mean achieving characterization from the atom-scale to the nanoscale. Key geochemical processes and phenomena – such as ion exchange and transport, redox reactions, adsorption – occur at complex geochemical interfaces, interlayers and within the pore space. These can be rationalized in terms of the surface structure and geometry, composition and reactivity. Improved knowledge of those processes will develop new geochemical concepts and further technological applications of interfaces in solid and porous media. In this session, we bring together researchers in computational and analytical methodologies that can unravel geochemical interfaces at the smallest scales. All applications to pollutants and contaminants transport and remediation, carbon sequestration, construction, mineral formation and of course geochemistry are welcome.

Full understanding of geochemical events at the smallest scales would mean achieving characterization from the atom-scale to the nanoscale. Key geochemical processes and phenomena – such as ion exchange and transport, redox reactions, adsorption – occur at complex geochemical interfaces, interlayers and within the pore space. These can be rationalized in terms of the surface structure and geometry, composition and reactivity. Improved knowledge of those processes will develop new geochemical concepts and further technological applications of interfaces in solid and porous media. In this session, we bring together researchers in computational and analytical methodologies that can unravel geochemical interfaces at the smallest scales. All applications to pollutants and contaminants transport and remediation, carbon sequestration, construction, mineral formation and of course geochemistry are welcome.

Full understanding of geochemical events at the smallest scales would mean achieving characterization from the atom-scale to the nanoscale. Key geochemical processes and phenomena – such as ion exchange and transport, redox reactions, adsorption – occur at complex geochemical interfaces, interlayers and within the pore space. These can be rationalized in terms of the surface structure and geometry, composition and reactivity. Improved knowledge of those processes will develop new geochemical concepts and further technological applications of interfaces in solid and porous media. In this session, we bring together researchers in computational and analytical methodologies that can unravel geochemical interfaces at the smallest scales. All applications to pollutants and contaminants transport and remediation, carbon sequestration, construction, mineral formation and of course geochemistry are welcome.

Atomic-scale models of earth materials are critical to developing larger-scale models of complex geochemical processes from the bottom up. Over the past decade, high-resolution experimental and computational studies have revealed that metastable and inherently disordered intermediates are ubiquitous during mineral nucleation and growth. Similarly, defect structures can also strongly influence mineral growth at both early and late stages. Establishing accurate chemical and structural models of intermediate phases, amorphous phases, and defect structures presents a significant challenge due to a lack of representative standards and structural analogues. Thus, novel experimental and theoretical approaches are needed to determine the structure, stability, and geochemical significance of these disordered phases and defect structures and defect structures over multiple length and timescales.

This session seeks contributions from various scientific disciplines that advance the current experimental and theoretical efforts to characterize the short- to long-range order of geochemically relevant materials, including biominerals.  We invite contributions that present novel syntheses, characterization approaches, computational methods, or large-scale modeling approaches that advance our understanding of inherently disordered materials and their importance in geochemical systems.

Topics of interest include, but are not limited to:

• Mineral nucleation and growth in confinement and on surfaces
• Defect structures and evolution in minerals
• Structural implications of dopants/impurities
• Amorphous and metastable intermediates to mineral formation
• Biomineral formation and bio-inspired mineralization approaches

Geochemistry increasingly relies on accurate and precise measurements of elemental concentrations and isotopic ratios within mineral grains using micro- and nano-beam instruments.  Compositional variations at (sub-)micron scales may preserve a record of crystal precipitation or thermal re-equilibration events; melt (fluid) infiltration; changing redox conditions; crystal strain related to tectonism; or low-temperature, surficial weathering induced by biochemical reactions and climate change. Radiogenic isotopic ratios may date these events, providing novel insights into the timing and rates of lithosphere – hydrosphere evolution and environmental change during Earth history.

For many microbeam instruments (e.g., electron probe microanalysis, secondary ion mass spectrometry, laser ablation-inductively coupled plasma-mass spectrometry, micro-X-ray fluorescence), reference materials are necessary for calibration of signal intensities or correction of instrumental mass discrimination.  Even where this is not the case (e.g., atom probe tomography), or where instrument responses are largely independent of the composition and form of target matrices, reference materials matched to analysed mineral matrices are useful as ‘secondary standards’ for method validation and quantification of accuracy and precision. For Big Data applications, where very large numbers of mineral analyses are made over weeks to months, matrix-matched reference materials are invaluable for documenting long-term reproducibility and levels of inter- and intra-grain homogeneity.

This session solicits presentations that characterize new reference materials for micro-/nano-beam analyses of elemental concentrations and isotopic ratios (including radiometric ages) of minerals; give new results for reference values and homogeneity of reference materials already in use; and demonstrate how reference materials support novel method development and Big Data science.

A large amount of observational and experimental chemical data (covering the atmosphere, hydrosphere, solid Earth, and planetary bodies) has been collected and accumulated over the years. With the development of mathematical algorithms and computational capacity, information previously hidden in these geochemical data can be revealed to enhance our understanding of the mechanism driving the Earth system. This session invites researchers with a broad range of expertise interested in data-driven approaches to elucidate the unresolved mysteries of Earth, environmental and planetary science through compositional data analysis, graphical analysis, data compilation on atmospheric, hydrological, sedimentary, mineralogical, and petrological geochemistry data. We also welcome contributions covering data infrastructures and the development of (meta)data standards, vocabularies, and best practices that facilitate the synthesis and reuse of global geochemical data.

The mobilization of metal(loid)s and radionuclides from natural and anthropogenic sources such as mine tailings, battery residues, and radioactive wastes lead to contamination of the natural environment, causing health and ecosystem problems. Harmful elements such as rare earth elements (REE), As, Se, Pb, U, and Zn (redox-sensitive and/or essential nutrients), can be released from these sources during (bio)geochemical processes (i.e., (trans)formation, sorption, and redox reactions). Hence, examining surface reactions of these Earth materials is essential for the prediction of the mobilization of toxic elements into the environment. Among various analyses, X-ray spectroscopy is a powerful tool to unravel elemental distribution and speciation (i.e., oxidation state, molecular environment) in complex matrices and study the atomic-scale geochemical reactions that occur at the water-mineral/rock interfaces. Understanding geochemical processes controlling elemental speciation of hazardous elements at surface sites can reveal pathways of contaminant mobilization and accumulation, and aid prediction of the environmental risk. We encourage your contributions to understanding the geochemical behaviors of inorganic and organic bound toxic contaminants with the application of synchrotron-based techniques to describe the following topics:

1. In-situ reaction at the liquid-solid interfaces
2. Rare earth element X-ray spectroscopy 
3. Metalloids and radionuclides behavior in natural and anthropogenic systems
4. Elemental mapping using X-ray and other spectroscopic techniques to unravel contaminant distribution in complex matrices

Your submission of multidisciplinary research can include the various utilizations of synchrotron-based techniques, with special emphasis on X-ray spectroscopy analysis in understanding the geochemical behaviors of anthropogenic contaminants that are of environmental and human health importance.

Interfacial chemistry controls  fate and transport of chemical species in surface water, soil, and atmosphere, shaping climate and sustaining life. This symposium will highlight recent experimental, theoretical, and modeling advances describing chemical processes at solid-water interfaces at all scales, from atomistic- and molecular- to reservoir- and planetary-scales. The topics of interest include interface structure and reactivity, nano-confinement effects on interfacial chemistry, ion adsorption-desorption rate and mechanisms, chemical and biological controls on mineral nucleation, growth and dissolution, interfacial redox reactions, and the effects of organic matter on surface reactivity. We invite research contributions on clean, ideal(ized) interfacial systems, as well as on natural samples with inherent compositional and structural complexities. The goal of this session is to bring together multi-disciplinary research group to discuss state-of-the-art and future research needs to advance the science of solid-water interface. Presentations will focus on fundamental science, as well as on the new experimental designs and technical developments for interrogating clean, as well as complex solid-water interfaces, and those undergoing transformation during dissolution-nucleation-growth process.

Reactions forming, consuming, and transforming solid materials, especially at the nanoscale, often proceed through a series of intermediates forming a dense energy landscape of possible structures and pathways. This landscape determines both the thermodynamically accessible metastable states and the barriers between them, determining which minerals can and cannot be observed during biomineral formation, in geochemical processes including redox reactions, isotopic fractionation, hydrothermal transport and deposition, phase transformations in the deep Earth, microbial biofilm deposition, sedimentation and diagenesis, weathering, fossilization, in engineered systems including disposal of nuclear waste in geological repositories and CO2 sequestration and H2 storage in underground formations, as well as the synthesis and degradation of and catalysis by synthetic and technologically important materials. Energy landscapes and structure at the molecular, nanoscopic, mesoscopic and macroscopic scales provide a complete description of all these systems, yet only a handful of them have been characterized thoroughly, including both experimental and theoretical approaches. This session aims to bring together participants from the biomineralization, geochemistry, mineralogy and materials community to explore the common features of energy landscapes and transformations in complex systems, including, but not limited to, carbonates, phosphates, transition metal oxides, silica, silicates and porous materials. The roles of interaction at surfaces and interfaces, also involving organic molecules ranging from simple molecules to proteins and polysaccharides, will be welcomed.

Subsurface mitigation is essential and attracts more and more attentions. Molecular simulation is an useful tool to reveal the nature at molecular scale. During subsurface mitigation, the interaction between solid-liquid-gas expresses multiscale characteristics and it's necessary to reveal the complex interaction behavior at molecular scale. This session welcomes molecular simulation investigations including molecular dynamics simulations, Monte Carlo, and etc.

Synchrotron X-ray scattering and spectroscopic techniques have made tremendous contributions to geochemistry by visualizing and quantifying the structural and chemical properties of geological materials at the atomistic to microscopic scale. These capabilities have been vastly enhanced by the emergence of the new 4^th generation source of X-rays with higher brilliance and coherence. This session seeks original contributions on the study of geochemical and microbiological processes using state-of-the-art synchrotron techniques and analyses, highlighting advances in novel synchrotron methods and new opportunities that upgraded photon sources bring together to the geochemistry community and other scientific disciplines.

Topics of interest include, but are not limited to:

• Visualization of chemical and structural complexities of geological materials
• In-situ observation of molecular-scale reactions at geochemical interfaces
• Reaction kinetics and dynamics in geochemical systems
• Multi-scale characterization of geological materials and interfaces
• Development of new synchrotron techniques and algorithms
• X-ray data analysis with artificial intelligence

This session is dedicated to analytical methods and instrumentation used for interpretation of stable and/or isotopic measurements in cosmochemistry, climate science, nuclear non-proliferation, geochemical chronometry, biology, and/or geophysics. Where the emphasis of this session is to present and discuss the analytical protocols, both procedural and instrumental, used to make these challenging measurements for characterization of materials in the solid state, aqueous, molecular, or gas phase. Discussion of measurements and the evaluation of uncertainty should also be considered as part of submission to this session. We are soliciting concepts that demonstrate state of the art in detection limits, precision and/or analytical volumes and discussion about how to get to the next level for future material characterization. The interdisciplinary nature of this session is meant to stimulate cross pollination of methodologies and application spaces.

As the search for life extends deeper into the solar system and beyond, many missions are targeting very promising and challenging planetary bodies. For these very inspiring but sophisticated missions, many challenges have to be overcome. These future planetary missions will be equipped with next-generation instruments producing more data than can be sent back to Earth, while facing severe operations and transmission limitations (e.g., communication delays and limited bandwidth, harsh environment, etc). The ability to autonomously detect signals of scientific interest onboard could enable data prioritization to increase mission science return from outer solar system targets. To maximize the value of each bit in order to achieve their mature science goals within these missions’ time and volume constraints, it is clear that future planetary bodies missions will require more autonomy. We investigate the applicability of data science and machine learning (ML) techniques on planetary data missions and laboratory analogs data as a case study for development of new strategies for planetary missions operations.

This session invites submissions from all relevant research areas (e.g.,  planetary science, analytical chemistry, field or laboratory geochemistry, geobiology, computer science), with the purpose of sharing research ideas and current investigations on the development of consistent methods, as well as on-board software and potential more autonomous flight instruments for the interpretation and analysis of data from planetary missions. Particular emphasis is given to work that can be applied for in situ exploration and onboard mission deployment.

As the search for life extends deeper into the solar system and beyond, many missions are targeting very promising and very challenging planetary bodies. For these very inspiring but sophisticated missions, many challenges have to be overcome. These future planetary missions will be equipped with next-generation instruments capable of producing vastly more data than can be sent back to Earth, due to severe operations and transmission limitations (e.g., communication delays and limited bandwidth, harsh environment, etc). The ability to autonomously detect signals of scientific interest in-situ could enable data prioritization to increase mission science return from outer solar system targets. To maximize the value of each bit and achieve their mature science goals within mission constraints, it is clear that future planetary bodies missions will require more scientific autonomy. We investigate the applicability of data science and machine learning (ML) techniques on planetary data missions and laboratory analogs data as a case study for development of new strategies for planetary missions operations.

This session invites submissions from all relevant research areas (e.g.,  planetary science, analytical chemistry, field or laboratory geochemistry, geobiology, computer science), with the purpose of sharing research ideas and current investigations on the development of consistent methods, as well as on-board software and potential more autonomous flight instruments for the interpretation and analysis of data from planetary missions. Particular emphasis is given to work that can be applied for in situ exploration and onboard mission deployment.

Hydrated (alumino)silicate phases are of capital importance for a score of applications ranging from zeolite catalysts to low carbon cement and concrete. These applications have spurred in depth research ranging from identification of suitable reactive primary and secondary resources as precursors down to the thermodynamic stability and kinetics of formation of the hydrate products as well as into the molecular level mechanisms controlling their degradation.

This session aims at convening experts from a range of interdisciplinary research fields to discuss and combine their latest insights.

Topics of interest include: Chemistry and reactivity of precursor materials including natural resources such as volcanic glasses and clays or waste materials such as slags. Treatments to increase precursor reactivity, including mineral carbonation, thermal activation and leaching. Alkali-silica reaction of aggregates in concrete. Experimental and modelling approaches to aluminosilicate hydrate nucleation, (re-)crystallisation and the coupling between dissolution and precipitation kinetics, stability and solubility. Analytical advances for characterization and in situ reaction monitoring, including embedded sensors, X-ray and neutron imaging, diffraction and scattering techniques as well as spectroscopic characterisation (Raman, NMR, XAS, HEXS). Molecular level descriptions of precursors, speciation, nucleation, growth, and assembly of (alumino)silicate hydrates. The chemical affinity of inorganic and organic ions and their inhibiting, catalysing or templating action.

Advocating a multidisciplinary scope, this session aims to be a nucleation centre for integrative thermodynamic, kinetic and structural approaches striving to elucidate (alumino)silicate hydrate formation spanning the spectrum from zeolite synthesis to cement hydration.

Over the past five years the interest in molecular hydrogen (H₂) has soared: the energy transition in many economies is considering H₂ as main energy carrier. So understanding possible reactions during subsurface storage of H₂ and the prospects of finding natural H₂ occurrences in quantities of economic interest are high on the agenda. Recent drilling of H₂-rich intervals, review of old petroleum and mineral datasets as well as findings of H₂-rich gases and fluids in soils or the continental crust have underlined the importance of elucidating the natural H₂ cycle well beyond the research on subseafloor hydrothermal vents whilst advancing the large-scale usage of H₂ as energy carrier – with possible release into the environment.

This session will combine contributions investigating the reactions, processes and kinetics of formation or oxidation of H₂: during water-rock interaction on mineral surfaces, consumption by microorganisms, and formation by corrosion and radiolysis. Presentations from both experimentalists and modelers will foster the exchange of available data and models. Additionally, it will integrate research on controls of H₂ migration – as loss from subsurface storage, possible pressure-release mechanism during the long-term storage of high-level nuclear waste or in the context of natural hydrogen fluxes in marine (e.g. hydrothermal) and continental settings. And it will outline avenues to and results from recent exploration endeavours for natural H₂-rich gases and fluids. Besides H₂ the session will incorporate new findings and exploration work on helium, as both gases require new approaches different from the hydrocarbon exploration and resource assessment.

This session focuses on aqueous geochemistry of mineral formation, geochemical processes that lead to the formation of metal ores, and the processes that dictate the fate of mine waste as it interacts with the atmosphere and hydrosphere. Geochemical research contributions that explore these broad scientific areas either at the fundamental level or via case studies are welcome. Of particular interest are studies focused on quantification and modeling ore-forming processes at various scales ranging from molecular-level modeling and predictions, to refining the chemistry/thermodynamics of these processes, and simulating large-scale fluid-rock interactions in geologic systems. Theoretical and experimental studies on mineral solubility, aqueous metal speciation in fluids, hydrothermal fluid properties, mineral dissolution or precipitation kinetics, as well as field studies shedding new light on ore formation and tailings reactions are examples of contributions that are also of interest.   This symposium is held in honor of the late Professor Dr. Hubert L. Barnes.  Hu Barnes was a leader in the field of ore deposit research and transformed our understanding of the formation of hydrothermal ores.  He developed novel techniques to study hydrothermal processes and devoted his career to advancing our understanding of ore-forming processes, mineral reactivity, and he developed solutions to address the environmental impacts of mine waste.  In addition, Hu Barnes was a leader in the research community and, among many other contributions, launched the Goldschmidt Conference series. 

To keep global warming caused by anthropogenic greenhouse gas (GHG) emissions below 2°C it is widely accepted that, in addition to significant and rapid GHG emission reductions, mainly carbon dioxide (CO₂) will need to be actively removed from the atmosphere and be permanently stored. Various engineered and nature-based solutions for CO₂ removal, storage and utilisation are being explored on land and in the oceans. These include direct air capture with carbon storage in sub-surface reservoirs, carbon mineralisation, enhanced rock weathering, biochar, and ocean alkalinity enhancement. Many of these strategies make use of the waste or by-products of the energy and mineral resource industries, stimulating global circular carbon economies.

This session will focus on a wide range of geochemical, biogeochemical, and mineralogical aspects of carbon dioxide removal and storage in a range of reservoirs and environments. We invite contributions from all aspects of carbon dioxide removal research, including lessons from natural systems, assessment of storage potential, reservoir permeabilities and possible migration pathways, geochemical and numerical modelling, fluid-rock interaction studies, using CO₂ for enhanced oil recovery, fundamental mineralogy, laboratory experiments, biogeochemical approaches, carbonation of diverse wastes, and utilisation of carbonated products. We also invite research exploring environmental, social, and governmental challenges related to carbon removal strategies.

Anthropogenic climate change is driving carbon neutral solutions for energy generation, resulting in renewed interest in nuclear energy. This has propelled a revived effort in the relevant materials associated with the nuclear fuel cycle, the geochemical stability of nuclear waste forms, and the effects of extension of remaining reactor life on structural concrete components. With the extension of existing reactors, new designs (Gen IV) and high burnup nuclear fuels these processes include: (i) studies of radiation damage and the related chemical transformations in structural materials such as cement matrixes and minerals in aggregates; (ii) characteristics and long-term performance of waste forms, (iii) mineralogical and mechanical evolution of the compartments of a multi-barrier system including interfaces between dissimilar materials, (iv) sorption of radionuclides to relevant mineral phases in the multi-barrier system and the formation of secondary phases / solid-solutions, and (v) radionuclide sorption and migration behaviour in the host-rock formation. These processes are controlled by thermodynamics and reaction kinetics that can be affected by radiolysis in the repository and the hydrodynamic regime. A mechanistic understanding of the processes from the molecular to the macro scale is essential to provide scientific support of the safety case for deep geological nuclear waste repositories.

With this session, we aim to bring together researchers working in these fields. Contributions from experimental and modelling studies aiming to improve our understanding of mineralogical, geochemical, and hydrogeological processes relevant for the maintenance of nuclear infrastructure, nuclear fuel and safe disposal of nuclear waste are welcome in this session.

The global transition to renewable energy and electrified transport is driving demand for metals, including for Cu, Co, Ni, Li, and the REE, as well as speciality materials such as graphite. Recycling alone cannot supply sufficient material and extraction from geological resources is needed. Research on mineral systems has intensified and diversified in recent years due to advances in analytical techniques and data processing, resulting in significant progress in our understanding of the petrogenesis of ore deposits and improvements in exploration targeting. This session invites contributions from field, geochemical, experimental, geophysical, petrophysical and numerical modelling studies that explore the origin, geodynamic setting, igneous, hydrothermal and supergene evolution of critical raw material systems, and of new low-impact ore processing technologies. Ensuring traceability of supply for these critical raw materials through geochemical fingerprinting will allow consumers to determine where their products originate and where environmental standards have been met. Integration of diverse approaches will streamline exploration for the geological resources that are critical for realisation of the renewable energy transition.

With the ongoing global efforts towards decarbonization, the use of the subsurface (e.g., for geothermal energy extraction, CO₂ sequestration, H₂ storage or even nuclear waste disposal) will increase. The underlying hydro-geochemical processes in these subsurface applications can lead to changes in chemical properties, the pore architecture and transport and mechanical properties of the rock matrix with a potential risk of contamination of our groundwater resources. Emerging cross-scale experimental and modelling approaches are needed to generate spatio-temporal insights into hydro-geochemical processes with realistic descriptions of the subsurface evolution and contaminant transport. This session provides a platform to discuss these exciting novel experimental and numerical approaches. We welcome contributions that focus on recent developments including but not limited to: (i) novel experimental methodologies for characterizing reactive fluid transport in porous media, (ii) theoretical and numerical studies of coupled hydro-geological processes in porous media (iii) upscaling approaches (iv) AI based tools to speed up experimental analyses, geochemical modelling or for upscaling methodologies (v) geochemical modelling and groundwater geochemistry.

Mineral resources are essential to the energy transition, particularly those related to critical raw materials such as REE, Li, Co, V and Sc, but there is a need to recover them with the least possible environmental impact. This session will focus on secondary and unconventional resources, including those associated with mine tailings, wastes, geothermal brines, mine waters and thermal springs. New extraction approaches for these resources are under development but not widely commercially applied. This session will concern all aspects of secondary and unconventional resources, from resource assessment through processing to mine waste mitigation. We invite abstracts that cover one or more of the following: (1) field studies of natural or anthropogenic systems with elevated metals; (2) experimental, thermodynamic and modeling studies of natural or engineered systems; (3) innovative approaches and simulations for mineral processing and metal extraction for relevant metals; (4) studies of microbial interactions with critical raw material systems; and/or (5) effective management, mitigation and use of secondary and unconventional resources.

Energy-critical elements (ECEs) include Li, the rare earth elements (REE, including Sc and Y), Re, Co, the platinum group elements (PGE), Ag, and photovoltaic ECEs including Ga, Ge, In, Se, and Te.  Accurate knowledge of geochemistry, including aqueous geochemistry, of ECEs, play an important role across a wide range of fields from hydrometallurgical extraction of ECEs from various sources, to elucidation of formation of mineral deposits with ECEs, and to the performance assessment of deep geological repositories for nuclear waste.  The safe disposal of nuclear waste is the key component of the nuclear fuel cycle.  REEs are excellent analogs to actinides, and Re is an analog to Tc.  Actinides, Tc, Se, and PGE are important components of nuclear waste. 

We invite contributions advancing geochemistry, including aqueous geochemistry, of ECEs, utilizing a variety of approaches.  Contributions include geological investigations of ECE mineralization, coupled with thermodynamic modeling in natural systems, fundamental experimental and theoretical approaches such as molecular simulations, solubility measurements, and speciation and spectroscopic studies.  We also welcome contributions that address the chemistry of geo-fluids and minerals that are relevant to the formation of ECEs mineral deposits, the partitioning of elements among phases, and the solvent/solute properties that can be applied to the evaluation of ECEs geochemical behavior in the geological repositories or to hydrometallurgical extraction of ECEs.  By the integration of these topics, our objective is to shed new light on the frontier research on fluid-dominated processes that control the mobilization of ECEs and their mineralization in the Earth’s crust.

Climate change and environmental degradation are an existential threat to the world. The political and economic strategy that will allow us to turn the current environmentally unsustainable global situation into a new sustainable paradigm implies the switching to usage of low carbon energy sources, the efficient use of materials, and the control of pollution sources. Interestingly, alternative energy sources will require the intensive use of metals and metalloids, increasing the stress on their sourcing, production and recycling. This is the case of antimony and bismuth. In this session, we plan to bring together geoscientists, chemists, and materials scientists interested in the cycling of antimony and bismuth in nature, in man-made, and engineered systems. The underlying physico-chemical conditions of the inorganic, organic, and biological processes are the same from the deep Earth to the surface of the Earth and in the industrial and recovery technologies. At the same time, given the many common characteristics of the vicinal element arsenic, we also welcome contributions from the large arsenic community to find out what can be learned from this element with respect to their cousins antimony and bismuth. The goal of the session is to establish the state of current knowledge and to identify promising venues that could help to enhance our understanding of how these elements behave, where do they come from, where are they heading, and how can they become a part of circular economy.

Combined efforts of carbon capture, utilization, and storage are needed to mitigate climate change effects and limit global warming to below 1.5°C in the 21^st century. Various geochemical, physico-chemical and biological processes and their combination critically impact CCUS. This session focuses on contributions related to all aspects of CCUS including 1) lessons from natural systems, 2) assessment of storage potential, reservoir permeabilities and possible migration pathways, 3) fundamental understanding and applied development of innovative CO₂ capture methods such as direct injection, direct air capture, enhanced weathering and/or bacterial carbonatogenesis, 4) carbonation potential of diverse wastes generated by the minerals and energy industries, 5) conversion efficiencies and stability of the products, 6) potential utilization of carbonated products. This session aims to create a platform to facilitate a cross-disciplinary discussion that bridges from fundamental understanding to practical, applied consideration related to feasibility and efficiency of CCUS. We welcome contributions focusing on natural systems, laboratory experiments, field trials, thermodynamic modeling and simulations, environmental and socio-economic impact studies.

To keep global warming caused by anthropogenic greenhouse gas (GHG) emissions below 2^oC it is widely accepted that in addition to significant and rapid GHGs emissions reductions, mainly carbon dioxide (CO₂), will need to be actively removed from the atmosphere and be permanently stored. Various engineered and nature-based solutions for emissions reductions, carbon offsetting and CO₂ removal are being explored on land and in the oceans. This includes both geochemical and biological techniques, such as enhanced weathering, carbon mineralisation, biochar and ocean alkalinity enhancement. Many of these strategies make use of the waste or by-products of the energy and mineral resource industries stimulating global circular carbon economies. Central to the effective implementation of these sustainable GHG removal strategies at scale is the need to establish robust accounting and monitoring reporting and verification (MRV) across both academia and industry.

This session will explore the employment of (bio-)geochemical analytical techniques, modelling, and reliable geochemical proxies to answer key questions related to quantification of GHG removal, monitoring, verification, and optimisation of these removals. This session welcomes submissions from those focussing on laboratory experiments, analogue and field trials, in-situ monitoring/sensors, and modelling-based approaches. We also welcome submissions related to the other challenges to the deployment at scale of these techniques, including but not limited to societal, technical, and environmental issues.

Most chalcophile and siderophile elements belong to critical metals, which are essential to the economy and whose supply is in high demand with social development. In times of clean energy transition, critical metals become vital to secure the rapid development of new infrastructure required for transition to  low low carbon emission technologies and the electrification of tranport.

Scientists in earth sciences have recently started investigating critical metal deposits' metallogenesis and related minerals' metallurgy, but the essential information is still missing.

Chalcophile and highly siderophile metals become enriched and fractionate in both magmatic and hydrothermal processes leading to the formation of different types of ores. The partitioning of metals between silicate melts, minerals, and fluids strongly depends on intensive parameters such as temperature, pressure, oxygen and sulfur fugacities, as well as the composition of melt, fluid, and sulfide phases, all of which change significantly during the evolution of magmatic-hydrothermal systems. Hence, the partitioning behavior varies in tectonic settings such as mid-ocean ridges, oceanic islands, subduction zones, flood basalt provinces, and continental rift zones, leading to differences in metallogenic processes and ore type. Furthering our understanding of the metal speciation and partitioning behavior has the potential for new insights into large-scale geodynamic processes and the concentration of strategic metals at a local scale.

We welcome contributions from petrology, mineralogy, geochemistry, ore geology, economic geology, metallurgy, and environmental policy, that contribute to understanding ore-forming processes, the extraction of critical metals from minerals, or related global economic and ecological problems.

Geochemistry plays an important role in understanding the process of CO2 based sub-surface energy exploration and sequestration. This session will bring together scientists for better understanding the geochemistry process in CO2 enhanced shale oil/gas recovery, CO2 enhanced saline water recovery, CO2 sequestration in saline aquifers and other subsurface applications. Experimental and modelling advances are both welcome. The topics include but not limited to: adsorption/desorption/displacement process for shale oil/gas; geothermal hybrid systems such as geothermal-biofuel and using geothermal originated CO₂; heat transfer properties in rock fractures; salt precipitation, CO₂-water-rock geochemical reactions; interfacial tension and wettability for CO₂/CH₄/water/rock systems at high temperature, high pressure conditions for CO₂ sequestration and enhanced oil/gas extraction; permeability of rock fractures, et al.

The world is transitioning towards a zero-carbon economy and there is a high demand for critical metals (e.g., Li, Co, REE, V, Mo, Zn, Cu, etc.). Exploring new geological deposits along with developing innovative ways of extracting critical metals from reservoirs resulting from anthropogenic activities (e.g., mine tailings, urban mining, agricultural by-products) constitute a significant part of this green energy transition. Knowledge on fundamental processes that drive formation of natural and engineered deposits of critical metals would help refine exploration strategies. Identifying and developing processes that would improve critical metal recovery will also be key in the next decade. To reach these goals, we must go beyond the traditional approach that consisted in only considering the abundance of critical metals (e.g., bulk geochemistry) and embrace new paths and new techniques (e.g., those involving high resolution imaging, isotope ratios, speciation) that bring new insights into the geochemical controls at play. This session welcomes research presentations that spans across both fundamental and applied aspects of critical metal research. We encourage submissions that successfully used new analytical methods to characterize both natural and engineered critical metal deposits unravelling mechanisms involved in concentrating critical metals. A particular attention will be given to cross-disciplinary research as well as any initiatives leading to improve the recovery of critical metals from any types of deposits.

Critical metals include rare metals (e.g., Li, Be, Nb, Ta, Rb, Cs, Zr, Hf, W, Sn), rare earth elements (e.g., REEs, Y, Sc), scattered (e.g., Ga, In, Ge, Tl, Se, Te, Re, Cd) and precious (e.g., PGEs, Co) metals. Critical metals are widely used in low-carbon green-energy and high-tech developments, which results in fast-growing global demands. The crustal abundances of critical metals are low. Hundreds and thousands of times of enrichments of critical metals from their initial source rocks are necessary processes to form economically important ore deposits. Understanding of the enrichment processes in the crust-mantle system is fundamental to successful exploration. This session will welcome contributions that include the metallogenetic regularities and dynamics, geochemical behaviors and cycle mechanisms of critical metals in the crust-mantle interaction system, the transport and precipitation of critical metals in magmatic-hydrothermal, metamorphic, sedimentary and supergene processes. Contributions related to identify the microscale occurrences of critical metals in different minerals and mineral process/geometallurgy which are essential to efficient and clean utilization are also encouraged.

Mineral resources are essential to the energy transition, but the way they are extracted and the limited reserves pose a risk to the deployment of decarbonized energy production sources. In this context, it is necessary to develop new extraction processes with a lower environmental impact, and capable of processing secondary resources (mine tailings, wastes, brines, etc.). The use of processes involving aqueous systems is an answer to these issues, avoiding the drawbacks of pyrometallurgical or solvent extraction approaches.

In order to obtain a selective and efficient extraction, many innovations are developed based on reactions at the solid/solution interface. They take advantage of the exchange or adsorption properties of solids, either in their pure state, or after modification of their surface, or consisting in several phases with defined functions.

This session will survey the various approaches developed to extract strategic elements (e.g. Li, Co, V, Sc…)  from raw and secondary materials with reactive solids, including but not limited to layered double hydroxides and other ion-exchange phases, modified silicas or metal organic frameworks. We especially welcome contributions on innovative materials, new experiments, proof-of-concept studies and simulations on the extraction and stripping mechanisms of these critical elements.

This symposium focuses on aqueous geochemistry of mineral formation, geochemical processes that lead to the formation of metal ores and the processes that dictate the fate of mine waste as it interacts with the atmosphere and hydrosphere. Geochemical research contributions that explore these broad scientific areas either at the fundamental level or via case studies are welcome. Theoretical and experimental studies on mineral solubility, aqueous metal speciation in fluids, hydrothermal fluid properties, mineral dissolution or precipitation kinetics, as well as field studies shedding new light on ore formation and tailings reactions are examples of contributions that are of interest.  This symposium is held in honor of the late Professor Dr. Hubert L. Barnes.  Hu Barnes was a leader in the field of ore deposit research and transformed our understanding of the formation of hydrothermal ores.  He developed novel techniques to study hydrothermal processes and devoted his career to advancing our understanding of ore-forming processes, mineral reactivity, and he developed solutions to address the environmental impacts of mine waste.  In addition, Hu Barnes was a leader in the research community and, among many other contributions, launched the Goldschmidt Conference series.  

Rare earth elements (REY, including yttrium) and other critical metals (CM, e.g., Li, Mn, Co, Ni, Zn, Cu) are considered essential for the expansion of renewable energy sources and energy storage. Discharges from active or inactive mines, thermal springs, and other anthropogenic or environmental processes can release these elements into surficial ecosystems where they undergo geochemical transformations and interact with reactive minerals and organisms, altering their overall solubility, mobility, and recoverability. Capturing CMs from polluting outflows could provide an important source of these elements without the additional environmental disruption that would result from mining other potential reserves (e.g., ocean floor nodules). We welcome presentations that explore CM behavior in natural or engineered ecosystems, from subsurface flow to surface discharge to final incorporation in solids. We seek studies that incorporate on one or more of the following: (1) field studies of natural or anthropogenic systems with elevated CM; (2) microbial interactions with CM via culture-based or metagenomic investigations; (3) laboratory (bio)geochemical studies of CM behavior during fluid-rock-microbe interaction; (4) novel geochemical and isotope tracers for fluid-rock-microbe interaction; and/or (5) geochemical modeling of equilibrium and kinetic CM behavior in natural or engineered systems.

Prolonging the operation of nuclear reactors is a critical factor in meeting global power demand. The extreme irradiation doses that materials in nuclear plants are exposed to after 60 to 80 years of operation cycles may have a significant impact on their physical and chemical properties and these need to be understood to ensure safe and continued operation. Continued functioning of the nuclear fleet will also benefit from advances in processing and storage of the associated radiological waste. This session welcomes studies of irradiation damage and related chemical transformations in structural materials such as cement matrixes and minerals in concrete aggregates. Research involving different radiation sources (gamma rays, neutrons, and ions) and their effects on chemical and physical properties of cements and minerals including chemical stability and reactivity, dissolution rates, density, porosity, and mechanical performance among others are welcome. Investigations on the use of cement matrixes, other rock-like or glassy materials for radiological waste encapsulation are also encouraged. In addition, exploration of fundamental phenomena related to the storage and processing of radioactive waste including interfacial chemistry in radiation-generating environments is also of interest. Both modelling and experimental approaches are welcomed.

Glasgow Climate Pact, the outcome of the COP26 and a fruit of intense negotiations among almost 200 countries, reaffirmed the Paris Agreement to limit the temperature rise below 2°C above pre-industrial levels and to aim for 1.5 °C. This requires rapid reductions in global GHG emissions, including reducing CO₂ emissions by 45% by 2030 and achieving net zero by 2050. The recent IPCC report (2022) identifies different mitigation pathways to reach these goals, e.g. by implementing Carbon Dioxide Removal (CDR) techniques, including Carbon Capture, Utilisation and Storage technologies (CCUS). The CCUS encompasses a range of geoengineering, geochemical, and mineralogical processes that ultimately aim at structural, residual, solubility, or mineral trapping of CO₂. This session focusses on a wide range of geochemical, biogeochemical and mineralogical aspects of geologic sequestration in either porous media or in mafic or ultramafic reservoirs, including utilising these rocks as feedstock materials for mineral carbonation in an ex-situ scenario. Through this session, we will provide a platform for the discussion of recent advances and innovations as well as the pressing challenges of CO₂ sequestration at a multi-scale, field to atomic scale level. We invite contributions from all aspects of geochemistry; geochemical modelling; fluid-rock interaction studies; fundamental mineralogy and innovative analytical approaches that collectively determine storage potential, pathways and permanence. The submission of multidisciplinary studies is particularly encouraged, e.g. linking CO₂ sequestration with critical metals recovery; mine waste mitigation through mineral carbonation or CO₂ sequestration in geothermal systems.

Crystalline graphite, a major component of Li-ion batteries, has emerged as a critical commodity for the energy transition away from fossil fuels. Deposits of graphite can form in a range of geologic environments via metamorphic and hydrothermal fluid processes. All the geologic factors that culminate in a preserved, mineable deposit constitute the ‘mineral system’. This session welcomes contributions that improve our understanding of the mineralizing processes and geologic factors that lead to graphite occurrence across spatial regimes spanning nanometers to the deposit scale. We encourage studies that utilize new or innovative applications of geochemical, spectroscopic, or geochronological techniques, as well as studies that address questions like: What was/were the source(s) of carbon and fluid(s)? What mechanism(s) resulted in deposition, enrichment, or alteration of graphite? What was the timing of mineralization and were there multiple episodes? How is the industrial quality of the graphite dependent on the mineral system?

A sustainable planet is the endeavor of this century. This objective can only be met by limiting global warming at or below 1.5˚C–2˚C, which can only be accomplished through a large-scale transition to low-carbon economy. The shift is already in motion in the global market with significant increase in the deployment of solar panels, wind turbines, and batteries for electric vehicles. As a consequence, the demand for critical minerals such as lithium, cobalt, manganese, nickel, vanadium and graphite for batteries, or rare-earth element (neodymium in particular) for permanent magnets, has grown substantially. This has an important implication for a wide variety of industries, and notably for developing countries with large mineral endowments. A growing demand for critical minerals will not only foster exploration in new regions of different countries but will also encourage technological innovations in the extractive industry, wherever discovery of newer deposits will be limited. The proposed session aims to undertake an innovative and integrated approach of looking at critical minerals by linking big-scale geological processes to formation of critical minerals resources, in sustainable sourcing of these metals through geochemical fingerprinting, and in technological advancements needed in mining, exploration, processing, recycling,  and in technology materials value chains. The proposed session will be particularly useful for improving our scientific understanding of the mineral-system concept, which is key to exploration targeting, and in promoting synergy between the mining, metal and recycling industries, which will help to boost the technological transfer needed to transition to green energy.

With the ongoing global efforts towards decarbonization, the use of the subsurface (e.g., for geothermal energy extraction, CO₂ sequestration, H₂ storage or even nuclear waste disposal) will increase. The underlying hydro-geochemical processes in these subsurface applications can lead to changes in chemical properties, the pore architecture and transport and mechanical properties of the rock matrix with a potential risk of contamination of our groundwater resources. Emerging cross-scale experimental and modelling approaches are needed to generate spatio-temporal insights into hydro-geochemical processes with realistic descriptions of the subsurface evolution and contaminant transport. This session provides a platform to discuss these exciting novel experimental and numerical approaches. We welcome contributions that focus on recent developments including but not limited to: (i) novel experimental methodologies for characterizing reactive fluid transport in porous media, (ii) theoretical and numerical studies of coupled hydro-geological processes in porous media (iii) upscaling approaches (iv) AI based tools to speed up experimental analyses, geochemical modelling or for upscaling methodologies (v) geochemical modelling and groundwater geochemistry.

In the world of transition to clean-energy, and the rising demand of Li, are we ready to catch up with this demand and more importantly, safely, and sustainably reach those goals? With the growing demand for Lithium (Li) in the realm of Li Battery Value chain, there is an obvious need for more Li, which means we as geoscientist have to do better in finding such resources safely and sustainably. This session is designed to provide information on global Li resources from Li rich brines (Produces Water - Geothermal and Oil Field Brines) as well as hard rock primary sources (Pegmatiites). In this session, we want to welcome presentation, that uses multi proxy methods to better explore for Li. These include but not limited to the use of metal concentrations, compatable elements, isotopes as well as clay minerology.  We wish to bring innovative ideas collectively from several groups across the world and address the upcoming challenge to find enough of Li, and build towards a framework for identifying fertile regions for targeted Li exploration.

In order to mitigate the effects of anthropogenically-induced climate change and reach negative emissions, it is essential to develop numerous approaches to remove CO₂ from the atmosphere. One way to achieve this is via CO₂ mineralization where CO₂ is captured and stored in stable secondary minerals over long timescales. This process involves mineral weathering to both produce alkalinity and release desirable cations (e.g., Ca²⁺ and Mg²⁺) that can bind with carbonate anions to precipitate secondary carbonates (e.g., CaCO₃ and MgCO₃), a stable sink for CO₂. This may be achieved in low energy environments where weathering takes place under earth surface conditions, and sometimes, includes the use of chemical or biological additives to promote carbonation. Improving our understanding on the effectiveness and permanence of carbon removal strategies is important as it may alleviate pressure on the energy industry to construct energy intensive carbon capture facilities which are costly and time consuming.

This session will highlight research that is exploring low-temperature carbon capture and storage through CO₂ mineralization processes. This is inclusive of but not limited to carbonation via weathering of industrial waste such as mine tailings or steel slag, biomineralization for carbon capture and storage, or enhanced weathering in coastal, agricultural, and marine environments. This session welcomes a diverse range of abstracts from fundamental geochemical processes to laboratory and field-scale experiments to computer modelling. We also invite research exploring environmental, social and governmental challenges related to low-temperature carbon removal strategies to be shared in this session.

Mine waste has impacted environmental and cultural resources for millennia. From the Roman era mercury mines of Monte Amiata and Almedén to the archaic industry of copper mining in the North American Great Lakes region, the effluent of historical mining activity remains an ongoing environmental issue. Present mine water mitigation is complicated by an estimated 131,000 legacy mine sites in the United States. Natural attenuation using wetlands is an important tool in mine waste mitigation moving forward. However, other unremediated mine sites may have unforeseen inputs of trace metals into stream and riparian ecosystems used for natural attenuation. Further, alterations in temperature and precipitation through climate change can influence future weathering and translocation of these contaminants as destabilized soil organic matter in drying wetlands release retained trace metals. Downstream communities may be profoundly impacted if mine waste mitigation does not consider changes in hydrology and wetland ecology in the immediate future. We invite abstracts that cover topics involving the challenge of mining impact mitigation in a range of temporal contexts. Presentations on the overlap of mine waste remediation and social justice issues are particularly encouraged.

The global transition to renewable energy and electrified transport is driving demand for metals, including for Cu, Co, Ni, Li, and the REE. Recycling alone cannot supply sufficient material and extraction from geological resources is needed. Research on mineral systems has intensified and diversified in recent years due to advances in analytical techniques and collaborations with industry, resulting in significant progress in our understanding of the petrogenesis of ore deposits and improvements in exploration targeting. This session invites contributions from field, geochemical, experimental and numerical modelling studies that explore the origin, geodynamic setting, igneous, hydrothermal and supergene evolution of critical metal mineral systems, and of new low-impact ore processing technologies.

Hydrothermal fluids control the transport and re-distribution of elements in magmatic-hydrothermal systems from sub-magmatic high-temperature fluid-melt fractionation to low-temperature rock alteration and final precipitation in veins and ore deposits. Modern exploration of ore deposits is largely based on genetic models and quantitative understanding of ore-forming processes. Our ability to develop tools for the discovery of new economically exploitable resources, thus, greatly depends on the capabilities in quantification and modelling ore-forming processes at various scales ranging from molecular-level modeling and predictions, to refining chemistry/thermodynamics of these processes, and to simulating large scale fluid-rock interactions in geologic systems.

Here we invite contributions aimed at evaluation, characterization, and quantification of the processes occurring in course of fluid-mediated ore formation. Contributions of interest can include geological evidences coupled with fluid-driven reactive transport and thermodynamic modeling in natural systems as well as fundamental experimental and theoretical research including molecular simulations and solubility/speciation and spectroscopic experiments. We also encourage contributions that address the chemistry of these hydrothermal fluids and minerals, the partitioning of elements among phases, and the solvent/solute properties. Through the integration of these studies we aim to shed new light on the fluid-mediated processes that control the mobility of economic elements and ore deposition in the Earth’s crust.

Raw Materials are crucial components for a resilient and sustainable economy and society. Factors such as the current geopolitical pressures have put raw materials at the forefront of policies again. Actions such as the “European Minerals Act” push for e. g. a higher degree of self-reliant supply of raw materials, strategic alliances and stockpiling. Moreover, the realisation of a low-carbon society and the requirement of new technologies – especially in the light of the EU’s “Green Deal” – changes future raw material needs and sets a focus in strategic or critical raw materials.

A sustainable, responsible and reliable supply of primary raw materials needs accessible mineral deposits, efficiently productive mines, smelters and refineries. Although Europe has a long history in mining, it is still widely underexplored in particular with modern exploration methods. A good understanding of mineral systems, deposit geology, mine sites and remaining resources of historical sites are of utmost importance to assess the raw materials potential and to lower the risk to develop responsible resource exploration and extraction projects.

This session thus invites contributions focussing on mineral deposits, including prospection, exploration, and other mining activities that indicate a socio-economic importance for the European society in particular, helping to lower supply disruptions also on a regional level.

Carbon capture and storage (CCS) is arguably the most-effective approach to mitigate climate change. Despite being a greenhouse gas, CO₂ is a multipurpose chemical, demonstrating extensive applications in different fields. In CCS, not only is the rate of carbon emission to the environment controlled, but also CO₂ performs as a perfect EOR agent in various processes such as miscible gas flooding, carbonated-water flooding, and water-alternating-gas flooding to enhance the ultimate oil recovery. However, the thermodynamic behavior of CO₂ underground, its mutual interactions with rocks and fluids, and the geochemical reactions triggered by CO₂ are far from being fully understood. This session invites contributions on recent advances in carbon capture and storage in the following key areas: 1) CCS-EOR processes: laboratory study, simulation, upscaling, and implementation; 2) Underground CO₂ utilization: using CO₂-triggered smart materials to improve EOR processes and control underground fluid flow; 3) CCS and sustainability: economy of CCS, fulfilling green chemistry principles by practicing CCS, and CCS challenges for achieving carbon neutrality; 4) Carbonated fluid behavior: physical and chemical interactions of CO₂-rich phase with the formation rock and fluid; 5) De-risking CO₂ injection and storage in underground structures and monitoring the CO₂ plume. Experimental, numerical, and review studies on all key areas across different scales are welcomed.

The transformation to a sustainable society requires certain critical elements (e.g. Li, Sr, Co, He, rare earth elements), which are ideally recovered with low environmental footprint. Geothermal brines, mine waters, and even sea water are often enriched in at least some of these elements up to concentrations with potential economic value. Currently, research focuses on geothermal sites because co-mining of metals and gases from geothermal brines during heat and power production can be a solution for supply of climate neutral energy and (critical) raw materials.

Different methods for the extraction of these critical elements from fluids are under investigation but only few have been applied to real brines yet. There are several unknowns, e.g. temporal and spatial variation in brine and gas chemistry, and numerous challenges, like high salinity, selectivity or interference with heat extraction, which still need to be addressed by science, industry and politics. The development of adapted and ideally sustainable methods to extract any kind of critical elements or gas, however, requires a thorough knowledge of these parameters.

We invite contributions that characterize the complexity of saline waters and their content of critical raw materials in the context of the regional geologic setting, studies investigating extraction methods for certain elements, and contributions focusing on the sustainability of element recovery, and related economic and environmental aspects.

The organic-rich shale from northern Guizhou in the Yangtze plate is a landmark deposition in South China from the Neoproterozoic to the early Paleozoic age, while the sedimentary evolution model of this organic-rich shale remain unclear, and the enrichment mechanism and organic matter (OM) model must be established. In our research, this set of organic-rich shale and sediments from the same period in northern Guizhou were taken as the research objects, and the OM enrichment model were established, which provides a reference for research on the sedimentary environment evolution of the organic-rich shale during the transition from the Late Sinian to the Early Cambrian in China and worldwide.

The original OM deposited in the organic-rich shale of the Niutitang Formation mainly originated from marine plankton, and this stage was also the main episode of the "Cambrian explosion of life". In the early deposition stage of the Niutitang Formation, the water in northern Guizhou was generally in an undercompensated state, and organisms died and slowly deposited, forming the organic-rich shale (Fig.1). As the plate movement, strong tension occurred in the mainland, and a deep fracture occurred in the basement strata, which caused crustal hydrothermal upwelling and provided a large number of nutrients (such as P and Si) for the water, resulting in the explosion of hydrothermal organisms, leading to the emergence of thermal vent biota in the organic-rich shale and providing sufficient sources for the OM of shale in the Niutitang Formation.

Anthropogenic climate change is driving carbon neutral solutions for energy generation, resulting in renewed interest in nuclear energy. Thus, the safe management of nuclear waste in deep geological repositories is a large challenge. To address this an understanding of the relevant mineralogical, geochemical, and hydrogeological processes is required. With the advent of new reactor designs (Gen IV) and high burnup nuclear fuels these processes comprise: (i) characteristics and long-term performance of waste forms (such as spent nuclear fuel, glasses, concrete, and ceramics), (ii) mineralogical and mechanical evolution of the compartments of a multi-barrier system especially at the interfaces between dissimilar materials, (iii) sorption of radionuclides to relevant mineral phases in the multi-barrier system and the formation of secondary phases / solid-solutions, and (iv) radionuclide sorption and migration behavior in the host-rock formation. These processes are controlled to a varying degree by thermodynamics and reaction kinetics that can be affected by the radiation field in the repository and the hydrodynamic regime. A mechanistic understanding of the processes from the molecular to the macro scale is essential to provide scientific support of the safety case for a deep geological nuclear waste repository.

With this session, we aim to bring together researchers working in these fields with a particular emphasis on the waste form/barriers in deep geological environments. Contributions from experimental and modeling studies aiming to improve our understanding of mineralogical, geochemical, and hydrogeological processes relevant for the safe disposal of nuclear waste are welcome in this session.

Nature Based Negative Emission Technologies, NB-NETs (i.e. REEDs, Blue Carbon, Enhanced Weathering, Coastal Carbon Mineralization, Ocean Alkalinity and Mineralization, among others) have become sustainable Climate Solutions which can help us not only  to effectively reach our global climate targets before 2040, but also to contribute to improve our quality of life, while positively impacting the natural environment and our socioeconomic well-being. Despite the potential climatic, environmental and social benefits that the implementation of NB-NETs has shown in models and laboratory experiments, their effectiveness as the ultimate sustainable climate solutions is yet to be assess. This session welcomes contributions aiming to use multipronged approaches to: 1. Quantify the effectiveness of NB-NETs to remove greenhouse gases from the atmosphere, 2. Quantify potential feedbacks in a warming and anthropogenic  world, 3. Quantify the environmental impacts (positive and negatives) of their implementation at real scale, and 4. Determine their potential co-benefits to diverse ecosystems. Contributions aiming to develop geochemical approach to develop Verified Carbon Standards are specially encouraged to be submitted.

Dominant drivers of biogeochemical cycles during the Precambrian have been extensively studied over the past decades, thanks to the development and increasing precision of unconventional elemental and isotope proxies, in addition to a step increase in the number of conventional geochemical data (e.g. carbon and nitrogen isotopes) covering the first billions of years of Earth history at significant space and time scale resolution. However, disentangling the influence of climatic, biological, tectonic and diagenetic processes in the geochemical record is extremely challenging, especially when tentatively merging different geochemical signals, and can lead to paradoxical interpretations. In this session, we would like to deepen our understanding of the biogeochemical cycles of the early Earth by encouraging presentations of integrated geochemical dataset and evolutionary models but also presentations that address pitfalls in our current conceptual frame of interpretations. This session invites contributions that investigate ancient geological archives from the Precambrian, modern analogs, experiments on microbial mineral interactions and abiotic processes that participate to - and eventually obscure the - early biogeochemical cycles recorded in the rock record. Topics including environmental reconstruction of surface processes that drive life apparition and evolution as well as causes and consequences of Earth’s redox evolution are most welcome in this session.

Seafloor hydrothermal systems have profoundly influenced the chemistry, biology, and oxidation state of Earth’s lithosphere-hydrosphere-atmosphere system throughout Earth history. However, their very nature within the oceanic crust drastically limits the temporal extent of direct geologic observations of their existence. Thus, attempts to correlate seafloor hydrothermal processes with biological evolution, global elemental budgets, and global redox states throughout Earth history generally require interdisciplinary studies that integrate studies of modern analogues, extrapolations of the geologic record, novel laboratory experiments, and numerical models. In this session, we intend to host a forum for presenting and integrating these various sets of observations in order to focus the community’s efforts on answering key questions regarding chemical budgets and oxidation states on modern and ancient Earth. In particular, we invite contributions focusing on seafloor measurements of modern hydrothermal systems; studies of recovered oceanic drill core, obducted oceanic lithosphere, or proxy records in ancient sedimentary rocks; experimental exploration of seafloor (bio)geochemical interactions; and integrative numerical models that expand the spatiotemporal scales of these field and experimental observations. Specific focuses could include the role of igneous oceanic crust alteration processes in the geologic carbon cycle, the contribution of submarine volcanism to the oxidation state of the early Earth, changes in ocean chemistry associated with the relative balance of continental weathering and seafloor hydrothermal fluxes, and the relation between these factors and tempos and milestones of biological evolution.

Life and environment are intrinsically linked and their co-evolution through geologic time is dependent upon interconnected responses to drivers, feedbacks, and tipping points. Constraining the long-term evolution of the biosphere in terms of both biotic and abiotic processes is an ongoing challenge. A recent expert elicitation survey aimed at understanding prevailing views on the record of life and chemical environment through time, revealed a mismatch in opinions, as well as a variety of approaches, from across the international geoscience community.

How significant were changes in oxygen concentration for the emergence and diversification of early complex life? Is our understanding skewed by the gaps in the sedimentary and palaeontological records and/or analytical approaches?

We hope to encourage submissions that showcase multi-disciplinary approaches including, but not limited to; geochemical proxies, chronostratigraphy, biogeochemical modelling, and palaeontological investigations. These studies should attempt to infill gaps in our understanding of the long-term co-evolution of life and atmosphere-ocean oxygenation. To this end, we also welcome submissions that incorporate novel approaches and bring new perspectives on the history of life and environment, and poorly calibrated intervals of geologic history.

NOTE: This live event includes sessions 11aO2 and 8cO1, in that order, with no break between them.

Bio-essential elements such as P, N, Ni, Mo, Cd, Zn Co, Fe, and other trace metals may have played different but major roles as nutrients over geologic timescales. Their bioavailability is therefore critical in primary production, with significant implications for C and O cycles and, eventually, the evolution of life. However, there is ongoing disagreement about the conflicting role of some nutrients in early Earth's primary production. Despite collective efforts, major questions remain on how and why some elements became essential to building biomolecules, what controlled their provision to living organisms, and how different continental and atmospheric configurations contributed to this development. Aquatic (bio)chemical sediments such as carbonates, lithified microbial mats (microbialites and stromatolites), phosphates, cherts, and banded iron formations are abundant throughout Earth's history and may hold the key to studying the long-term evolution of dissolved bio-essential nutrients and interactions of the biosphere-atmosphere-hydrosphere systems with the geodynamical evolution of the Earth. Geochemical analyses of such archives are critical for extracting information on environmental conditions, geomicrobiological cycles, and post-depositional alteration in modern and ancient systems from natural materials' chemical and isotopic composition. We invite submissions that utilize geochemical and modeling, sedimentological and experimental approaches over a range of natural environments to address these questions and better understand the co-evolution of nutrients and other elemental supplies on Earth's habitats through deep time.

Our understanding of the modern and future Earth system depends on accurate reconstructions of Earth’s ancient environments, often based on geochemical measurements of sedimentary archives. However, sedimentation, lithification and compaction significantly alter primary geochemical fingerprints. Further complexities arise from microbe metabolic activities and/or abiotic dissolution-precipitation, occurring within the sediment column during and/or after initial deposition. Consequently, reliable paleo-environmental reconstructions heavily depend on our ability to identify and “see through” the various levels of isotope and chemical alteration known as diagenesis. These post-depositional processes must be understood and accounted for to reconstruct geochemical proxy records that accurately capture changes in Earth’s surface environments through geological time. Recent development of new geochemical analyses and modelling techniques have allowed for large advances in our understanding of how the geologic record preserves environmental information. This includes detailed studies of modern sediments, pore water fluids, sophisticated fluid-rock and/or reaction transport modeling as well as analyzing multiple isotope ratios or combining multiple element systems.

In this session, we invite all work that examines the preservation potential of various sedimentary archives and how it impacts the interpretation of environmental conditions across the geological time scale. The research can focus on a wide variety of proxy settings such as lacustrine, marine, metamorphic, hydrothermal, or continental, from Archean to modern. We aim to facilitate interdisciplinary discussions by inviting submissions that involve modelling, novel isotope proxy development, studying modern sediment-forming environments, geochronology, in-situ and bulk extraction techniques, or laboratory and modern analog experiments.

NOTE: This live event includes sessions 8fO2 and 8eO1, in that order, with no break between them.

Over the Phanerozoic Eon, the Earth witnessed several episodes of abrupt change in the surface environment and the biosphere. These included the ‘Big Five’ mass extinctions, ocean anoxic events (OAEs), rapid climate warming/cooling spells, and multiple other ‘more minor’ biotic crises. The perturbations in biogeochemical cycles during those times often led to the rapid and widespread disappearance of marine and terrestrial biota, as well as setting the stage for new ones to emerge. Although progress has been made in unravelling some of the factors and conditions driving abrupt environmental, climatic and biogeochemical changes during these events, there are still considerable shortcomings towards a holistic understanding of the underlying causes of these critical events, and the complex interactions between the physical, chemical and biological components of the biosphere during these time periods. Deconvolving the complex interactions between different components of the Earth system, including the solid Earth, hydrosphere, atmosphere, and biosphere during those episodes offers a better understanding of how the Earth operates as an integrated system, and also provides useful insights into possible Earth-System changes in the future. This session invites contributions that help to elucidate the driving forces behind these critical events (such as OAEs, PETM, K/Pg, end Permian, etc.) and the environment-biota interactions during intervals of rapid environmental change in the Phanerozoic. We welcome studies that use proxy, modelling and integrated approaches. The overarching aim is to foster discussion and synthesis of recent advances in the field.

NOTE: This live event includes sessions 8fO2 and 8eO1, in that order, with no break between them.

With advances in instrument precision and sample preparation protocols, stable and radiogenic isotope geochemistry techniques have proven to be some of the most powerful analytical tools to both date and characterize high and low temperature processes. This session aims to gather researchers focused on augmenting the capabilities of isotope geochemistry in terms of analytical methods, use of under-explored isotope systems and alternative ways to interpret conventional isotopes. We welcome contributions that present new approaches for improving our understanding of the Precambrian Earth where processes do not have any modern analogues (e.g., early crust formation, appearance of primitive microbial life, Snowball Earth, Great Oxidation Event), Phanerozoic events related to global environmental crises (e.g., Oceanic Anoxic Events, Large Igneous Provinces), and other geologic processes (e.g., geodynamics, ore formation, paleoclimate, element cycling). We particularly encourage abstract submissions from early-career researchers and scientists from groups that are underrepresented in geoscience.

Organic geochemical records of biosignatures—including molecular fossils, metabolic or physiological signatures, and isotopic tracers—provide a unique window into Earth-system evolution. Biosignature records allow for the reconstruction of both the biological processes mediating elemental cycling and the resulting co-evolution of the geosphere. Interpreting these complex records requires a process-oriented understanding of biosignature sensitivity to environmental, physiological, and evolutionary change. Modern systems including extant organisms, culturing experiments, genomic information, and analog environments allow us to build proxy frameworks used to reconstruct the geologic past. Ultimately, using modern processes to reconstruct past biogeochemical and organismic evolution may help us understand future Earth surface conditions.

In this session, we aim to bring together scientists interested in organic geochemical proxy development and applications. We invite contributions from researchers studying a broad range of systems—from pure cultures to terrestrial and marine environments—on all spatial and temporal scales. We particularly encourage contributions that transcend disciplines to integrate information from a variety of sources such as organic matter, biomarkers, isotopic compositions, genetic markers, experimental biology, and others. We also encourage submissions highlighting novel analytical, experimental, and modeling approaches as well as paleo-applications.

Active microbial communities colonize a wide range of habitats on the planet and even reach deep into the Earth’s crust. They are supported by a range of geological processes such as serpentinization, hydrothermal circulation, mechanochemical reactions, water radiolysis, and diagenesis of buried organic matter. However, the vast majority of microbes inhabiting these environments are currently uncultured and are often referred to as microbial dark matter. Since we lack pure cultures of these organisms, we are missing the experimental evidence for describing their physiological capabilities and metabolic functioning, and thus, their role in global biogeochemical cycles. This session aims to bring together researchers combining a variety of approaches to advance our understanding of the role that uncultured microbes play in these habitats, as well as the geological processes that sustain them. This knowledge is fundamental to predicting their behavior in future climate change scenarios. Further, advances in this multidisciplinary field not only improve our understanding of biogeochemical cycles on Earth but also act as proxies for research into the origin of life, the habitability of other planetary systems, and the co-evolution of Earth’s biosphere and geosphere.

Recent research has demonstrated the presence of active microbial communities throughout Earth’s crust and rock-powered habitats, spanning marine sediments, hot springs, hydrothermal vents, salt lakes, glacial systems, deep mines, boreholes, and permafrost. Many such environments are considered to be extreme, characterised by their harsh conditions for life, these can include extremes of temperature, pH or salinity; limitations in nutrient or energy availability; and other environmental hazards such as unusual radiation or pressure regimes. Geological processes such as serpentinization, hydrothermal circulation, mechanochemical reactions, water radiolysis, and diagenesis of buried organic matter support complex communities, many of which remain uncultured. Further afield, new extreme environments where water and rocks interact are being discovered and characterised throughout the solar system. Subsurface Lithoautotrophic Microbial Ecosystems (SLiMEs) are important oases for productivity and ultimately nutrient cycling. Thus, advances in this multidisciplinary field not only improve our understanding of biogeochemical cycles on Earth, such ecosystems also act as proxies for research into the origin of life, the habitability of the other planetary systems, and the co-evolution of Earth’s biosphere and geosphere. This session will showcase studies that expand our understanding of how subsurface microbial communities are supported by deep Earth processes, the unique geochemical reactions that occur in extreme environments, how they contribute to the coevolution of Earth and its biosphere as well as unexplored environments on earth and in other planetary systems. We welcome submissions from researchers using in situ or ex situ analysis, modeling or laboratory experimental techniques to further knowledge within these fields.

The vast majority of microbes on Earth are currently not cultured and are often referred to as microbial dark matter. Due to the inability to study these microbes in pure culture, we lack knowledge of their physiological capabilities. Understanding their metabolic functioning is key to recognizing their role in biogeochemical cycling. Sequencing of metagenomes and single annotated genomes has given us vital information on potential metabolisms of uncultured representatives. Although bioinformatic tools have advanced considerably, we face the difficulty that a high proportion of genes encoded on the genomes cannot be allocated to a function. Hence, a major challenge today resides in measuring in situ and interpreting the role of microorganisms for the regulation of global biogeochemical cycles. Besides advancing our comprehension of the role the uncultured microbial majority plays in biogeochemical cycling, this knowledge is fundamental to predicting their behavior in future climate change scenarios. Advances in geochemical imaging and fine-scale analyses as well as “multi-omics” approaches offer alternative perspectives to study microbial activity in the environment. This session aims to bring together researchers combining a variety of approaches to advance our understanding of the role that uncultured microbes play in the environment for bio-geo-coupling processes: (i) sequence-based analyses, cultivation-based techniques and incubation and isotope experiments which link metabolic activity to uncultured microbes; (ii) studies targeting key parameters of microbial activity (sources, fates, fluxes of substrates, metabolic products and microbial markers) and the biochemistry of enzymes; (iii) development of novel methods and biomarkers to trace microbial activity in situ.

We are interested in bringing together several scientific fields and experts to present holistic information surrounding some of the largest mass extinctions in the geologic past. Contribution dealing with interactions of the biosphere with the hydrosphere and atmosphere and of course the lithosphere are of special interest. Thus, multiple geochemical and biological proxies are paramount in demonstrating these dramatic events marking the evolution of the major spheres and the role they played in the evolution of life forms and life. We will entertain presentations dealing with all aspects of the global cycles (biological to geochemical) involved in the manifestation of the signatures left in the rock record using everything from traditional to novel geochemical proxies and markers. Also, modelling presentations are welcome, but they must demonstrate close association with either biological and/or geochemical support structures from the geologic record.

The evolution of the Precambrian Earth is characterized by major events that are often difficult to explain due to the absence of modern analogues. In this context, isotope geochemistry is an approach that is increasingly used for the characterization of environments and dating of processes that can be specific to Hadean, Archean and Proterozoic times. With the recent advances in instrument precision and sample preparation protocols, isotope geochemistry is becoming one of the most powerful analytical tools to constrain both the timing of major events in Earth history, but also determine the depositional environment, chemical conditions and global element cycling. This session aims to gather researchers focused on augmenting the capabilities of the isotopes in terms of analytical methods, of use of under-explored isotope systems or even on alternative ways to interpret conventional isotopes. We welcome contributions that present new approaches for improving our understanding of the processes active on the early Earth such as crust formation and geodynamics, as well as on major reversible and irreversible events throughout the Precambrian such as the appearance of primitive microbial life forms, the Snowball Earth, the Great Oxidation Event and the evolution of the atmosphere and ocean.

Aquatic (Bio)chemical sediments such as carbonates, lithified microbial mats (microbialites and stromatolites), phosphates, cherts, and banded iron formations are abundant throughout Earth’s history and formed under diverse environmental conditions. Recent advances in analytical procedures and proxy development approaches have improved our understanding of physicochemical conditions in ancient and modern marine and lacustrine environments. For this session, we invite contributions from the interdisciplinary fields of trace element, bio-, and isotope geochemistry, sedimentology, field geology, petrography, Raman spectroscopy, as well as experimental approaches that target (bio)chemical sediments of diverse aquatic (paleo)-environments to understand better the co-evolution of the atmosphere, hydrosphere, biosphere, and continental lithosphere from the early Archean until today.

In the course of the last 500 million years, the Earth witnessed the ‘Big Five’ mass extinctions and multiple other ‘more minor’ events of biotic crises, which led to rapid and widespread disappearance of marine and terrestrial biota and set the stage for new ones to emerge. The field of geochemistry has played a critical role unravelling some of the factors and conditions involved in these events, which are largely associated with volcanism from large igneous provinces and/or extra-terrestrial phenomena as drivers of abrupt environmental, climatic and biogeochemical change. Nevertheless, there are shortcomings in our understanding of the underlying causes of extinction, the complex interactions between the physical, chemical and biological components of the biosphere during these time periods, and the recovery of ecosystems in their aftermaths. This session invites contributions seeking to address these questions using both proxy and modelling approaches, and more broadly, any studies dealing with biogeochemical processes during periods of rapid environmental change. The overarching aim is to foster discussion and synthesis of recent advances in the field.

Biomarker proxies, underpinned by analytical and genomic innovations, have been crucial for our understanding of the evolution of Earth’s System across the Phanerozoic and beyond.

We welcome contributions that provide advances in the development of analytical methods and biomarker proxies (including their (stable) isotopes like δ¹³C and ¹⁴C) as well as those that apply biomarker proxies to reconstruct the operation of Earth’s system at present and across geological time. Examples include: new proxy calibrations, analytical and computational advances (e.g. untargeted molecular approach), advances in biosynthetic pathways, combinations of genomic surveys with biomarker proxies to understand modern biogeochemical processes, paleoclimate reconstructions (e.g. SSTs), reconstructions of carbon and nitrogen cycle dynamics (e.g. CH₄, CO₂, etc).

The Cryogenian interglacial manganese (Mn) carbonate deposits hosted in the Lower Member of the Datangpo Formation (DTP-1) black shales in South China have been interpreted to form predominantly through microbially-mediated processes. In this study, we suggest that massive metallogenesis of Mn as carbonate phase may have a potential impact on Neoproterozoic carbon cycle by serving as a special sink of bio-essential element phosphorous (P) and as a unique storage of inorganic carbon. The association of P with particulate Mn occurred upon the initial precipitation of MnO_x under pulsed oxygenation events during deglaciation. The fixation of P in authigenic Ca-Mn-carbonate phase during subsequent conversion of Mn oxides in organic-rich sediments might have facilitated retention of P, resulting in less efficient P recycling and thus slackened recovery of marine primary production. Positive excursion of nitrogen isotopic composition of Mn-rich samples (δ¹⁵N = +5.89 ~ +9.83‰, average = +7.96‰) is likely attribute to heavier seawater NO₃^- because of nonquantitative denitrification under relatively low input of organic matter. These likely have impeded rapid accumulation of O₂ in atmosphere-ocean system right after Sturtian glaciation. The Sedimentary Mn carbonate deposition in a notable scale may prevent the CO₂ produced by aerobic oxidation of organic carbon diffusing back to the surface system. Namely, it can be regard as a special microbial carbon pump, converting burial/dissolved organic carbon to inactive inorganic carbon. This process would provide an additional contribution for increased pO₂/pCO₂, paving the way for rapid rise of eukaryote algae in later stage of interglacial period.

Research over the past few decades has demonstrated the presence of active microbial communities throughout Earth’s subsurface, spanning marine sediments, marine and terrestrial hot springs, deep mines, boreholes, and deeply-buried permafrost. Geological processes such as serpentinization, hydrothermal circulation, buoyancy driven fluid seepage, water radiolysis, and diagenesis of buried organic matter support complex communities of microorganisms, many of which remain uncharacterized by laboratory culture. These subsurface microbial communities are key to understanding how Earth’s biosphere and geosphere have co-evolved over time, as studies of modern microbial ecosystems can be used to place metabolic and ecological functions in their geochemical and geological context. This session will showcase studies that expand our understanding of how the functions and composition of subsurface microbial communities are supported by deep Earth processes, and how they in turn have contributed to the alteration of these geological and chemical processes, resulting in the coevolution of Earth and its biosphere.

Our understanding of ancient environment relies on the geochemical information extracted from sedimentary archives. However, sedimentation, lithification and compaction are known to significantly alter environmental fingerprints. Further complexities arise from microbe metabolic activities and/or abiotic dissolution-precipitation that occur within the sediment column after the deposition. Consequently, reliable paleoenvironmental reconstructions heavily depend on our ability to identify and “see through” the various levels of isotope and chemical alteration commonly referred to as diagenesis. Recent development of new geochemical analyses and modelling techniques have allowed for large advances in our understanding of how the geologic record preserves environmental information. This includes detailed studies of modern sediments, pore water fluids, sophisticated fluid-rock and/or reaction transport modeling as well as analyzing multiple isotope ratios with high precision and in-situ, and combining multiple element systems.

In this session, we invite all work that examines the preservation potential of various sedimentary archives and how it impacts the interpretation of environmental conditions across the geological time scale. The research can focus on a wide variety of proxy settings such as lacustrine, marine, metamorphic, hydrothermal, or continental, from Archean to modern. We aim to facilitate interdisciplinary discussions by inviting submissions that involve modelling, novel isotope proxy development, studying modern sediment-forming environments, geochronology, in-situ and bulk extraction techniques, or laboratory and modern analog experiments.

Geochemical analyses coupled with modeling are essential for extraction of information from the chemical and isotopic composition of natural materials about environmental conditions, geomicrobiological cycling, and post-depositional alteration in modern and ancient systems.  Recent methodological advances have facilitated collection of geochemical data across a range of spatial scales (µm – km). These multi-scale, multi-proxy data have, in turn, enabled the development of more sophisticated process-based models to improve our understanding of the ecological and environmental evolution of the Earth’s surface environment.  We invite submissions that utilize combined geochemical and modeling approaches over a range of natural environments and disciplines with the goal of using the results to interpret the coupled evolution of life and the Earth surface system in the present and the past, as well as to better predict future changes.

The Paleozoic–Mesozoic Eras (~540–66 Ma) witnessed many episodes of dramatic changes in the surface environment and the biosphere. Outstanding examples are oceanic anoxic events (OAEs) and the “big five” mass extinctions. Undoubtedly, many of these events resulted from complex interactions between different components of the Earth system, including the solid Earth, hydrosphere, atmosphere, and life, but details of these interactions remain incompletely understood. Deconvolving these interactions allows for not only a better understanding on how the Earth operates as an integrated system, but also provides useful insights into possible Earth-system changes in the future. This session invites contributions that investigate biological, environmental, and climatic changes during the Paleozoic and Mesozoic period, using a variety of approaches, including, but not limited to, geochemistry, sedimentology, modeling, or big data/data mining. Research that focuses on elucidating the driving force(s) behind major Paleozoic and Mesozoic events, on co-evolution of life and the environment during this period, or utilizes “unconventional” approaches, is particularly encouraged. Researchers from all career levels are welcomed. We particularly encourage early-career researchers from diverse backgrounds to submit to our session.

Phosphorus is generally considered to be the limiting nutrient over geologic timescales, and therefore its bioavailability plays a central role in primary production, with significant implications for C and O cycles, and, eventually, the evolution of life. However, there are ongoing debates on the competing role of other nutrients such as nitrogen and bio-essential trace metals in the limitation of primary production on the early Earth. Despites collective efforts, it has been notoriously difficult to reconcile geochemical datasets, and major questions remain on how and why some elements became essential to the building of biomolecules, and what controlled their provision to life on the early Earth. This session aims to address these questions and formulate new hypotheses through cross-discipline studies including geochemical compilations, experimental insights and modelling. Key points of focus will be on nutrients cycles on the early Earth, the evolution of their marine reservoirs, of their contents in biomass, and on potential change-points linked to evolutionary steps.

Organic geochemical records of biosignatures—including molecular fossils, metabolic or physiological signatures, and isotopic tracers—provide a unique window into Earth-system evolution. Biosignature records allow for the reconstruction of both the biological processes mediating elemental cycling and the resulting co-evolution of the geosphere. Interpreting these complex records requires a process-oriented understanding of biosignature sensitivity to environmental, physiological, and evolutionary change. Modern systems including extant organisms, culturing experiments, genomic information, and analog environments allow us to build proxy frameworks used to reconstruct the geologic past. Ultimately, using modern processes to reconstruct past biogeochemical and organismic evolution may help us understand future Earth surface conditions.

In this session, we aim to bring together scientists interested in organic geochemical proxy development and applications. We invite contributions from researchers studying a broad range of systems—from pure cultures to terrestrial and marine environments—on all spatial and temporal scales. We particularly encourage contributions that transcend disciplines to integrate information from a variety of sources such as organic matter, biomarkers, isotopic compositions, genetic markers, experimental biology, and others. We also encourage submissions highlighting novel analytical, experimental, and modeling approaches as well as paleo-applications.

Our understanding of the modern and future Earth system is bolstered by precise and accurate reconstructions of Earth’s ancient environments. These reconstructions are based on (bio)geochemical measurements of sedimentary archives, but diagenesis and other post-depositional events often modify primary geochemical signals. These post-depositional processes must be understood and accounted for in order to accurately interpret geochemical proxy records and thus, capture changes in Earth’s surface environments through geological time. In many cases, the nature or magnitude of diagenesis contains in itself useful information. This session aims to bring together scientists applying a range of techniques to sedimentary archives across the geological timescale to quantify post-depositional alteration and its impact on geochemical proxies and paleo-environmental reconstructions or to use diagenetic signatures to deduce Earth surface conditions in deep time.

Through their use in geochronology and as geochemical tracers, radiogenic isotopes have proven to be a powerful tool in understanding geologic processes throughout Earth history. This session aims to bring together scientists who apply radiogenic isotope geochemistry to a range of geologic questions, including high and low temperature processes and geochronology. In doing so, we hope to spark discussions and collaborations to further the field and applications of radiogenic isotopes. We encourage abstract submissions from a broad range of disciplines (crustal evolution, sedimentology, paleoclimatology, economic geology), time scales (recent to Precambrian), and techniques. We particularly encourage abstract submissions from early-career researchers and scientists from groups that are underrepresented in geoscience.

Through their use in geochronology and as geochemical tracers, radiogenic isotopes have proven to be a powerful tool in understanding geologic processes throughout Earth history. This session aims to bring together scientists who apply radiogenic isotope geochemistry to a range of geologic questions, including high and low temperature processes and geochronology. In doing so, we hope to spark discussions and collaborations to further the field and applications of radiogenic isotopes. We encourage abstract submissions from a broad range of disciplines (crustal evolution, sedimentology, paleoclimatology, economic geology), time scales (recent to Precambrian), and techniques. We particularly encourage abstract submissions from early-career researchers and scientists from groups that are underrepresented in geoscience.

Extreme habitats are characterised by their harsh conditions for life, these can include extremes of temperature, pH or salinity; limitations in nutrient or energy availability; and other environmental hazards such as unusual radiation or pressure regimes. Yet, many extreme environments sampled to date (including hydrothermal vents, salt lakes, hot springs, glacial systems and the deep biosphere) have been shown to host an array of microbial communities, collectively known as extremophiles. Although our knowledge of these ecosystems is often limited, mineral-water reactions such as serpentinization, mechanochemical reactions and radiolysis have been suggested as a potential source of energy and nutrients for these microbial communities. Further afield, new extreme environments where water and rocks interact are being discovered and characterised throughout the solar system. Thus, advances in this multidisciplinary field not only improve our understanding of biogeochemical cycles on Earth, such ecosystems also act as proxies for research into the origin of life and the habitability of the other planetary systems. This session aims to highlight recent developments in our understanding of the unique geochemical reactions that occur in extreme environments, the microbial communities these reactions support, and the potential implications this has for life in yet unexplored environments on Earth and in other planetary systems. We welcome submissions from researchers using in situ or ex situ analysis, modelling or laboratory experimental techniques to further knowledge within these fields.

Research over the past few decades has demonstrated the presence of active microbial communities throughout Earth’s subsurface, spanning marine sediments, marine and terrestrial hot springs, deep mines, boreholes, and deeply-buried permafrost. Geological processes such as serpentinization, hydrothermal circulation, buoyancy driven fluid seepage, water radiolysis, and diagenesis of buried organic matter support complex communities of microorganisms, many of which remain uncharacterized by laboratory culture. Microbial metabolisms have adapted and radiated throughout this time, as the presence of oxygen helped create new bioavailable elements, carbon substrates, and other compounds. These subsurface microbial communities are key to understanding how Earth’s biosphere and geosphere have co-evolved over time, as studies of modern microbial ecosystems can be used to place metabolic and ecological functions in their geochemical and geological context. Subsurface Lithoautotrophic Microbial Ecosystems (SLiMEs) are important oases for productivity and ultimately nutrient cycling, and thus we have much to learn about how microorganisms have evolved to thrive in these ecosystems. Here we seek to shed light on SLiMEs' evolution using diverse proxies (element isotopes, geochemistry, modeling, lipids, or DNA/RNA/Protein) in ancient and/or extant systems. This session will showcase studies that expand our understanding of how the functions and composition of subsurface microbial communities are supported by deep Earth processes, and how they in turn have contributed to the alteration of these geological and chemical processes, resulting in the coevolution of Earth and its biosphere.

Microorganisms and more importantly microbial ecosystems have been prominent features of Earth’s crust and left their indelible mark throughout the geologic record. Consequently, microbial metabolisms have adapted and radiated throughout this time, as the presence of oxygen helped create new bioavailable elements, carbon substrates, and other compounds. Today we recognize that much of Earth’s microbial biomass lies buried in subsurface ecosystems. However, how these microbial ecosystems developed and evolved is still coming into focus due to the limited sampling of Earth’s crust. Subsurface Lithoautotrophic Microbial Ecosystems (SLiMEs) are important oases for productivity and ultimately nutrient cycling, and thus we have much to learn about how microorganisms have evolved to thrive in these ecosystems. Here we seek to shed light on SLiMEs' evolution using diverse proxies (element isotopes, geochemistry, modeling, lipids, or DNA/RNA/Protein) in ancient and/or extant systems.

Soils and fossilized soils provide crucial insight into characterizing regional environment and global climate. Major and trace element transfer, pedogenic carbonate nodules, bioturbation, and organic matter are just some of the properties used to build proxies that can reconstruct periodic changes in the environment and climate when integrated with sequence stratigraphic analysis. While techniques for understanding and analyzing pedology and paleopedology are relatively novel, the progression of using soils and paleosols to reconstruct climate has accelerated. This session invites soil and paleosol related research, especially but not limited to, studies that focus on the advancement of geochemical techniques and how soils and paleosols respond to changes in climate. Studies that investigate weathering processes, impacts of dust deposition, geochemical perturbation, and overall changes in paleo-critical zones under various climate states are also welcome.

The chemical alteration of rocks is central to a broad spectrum of fundamental and applied topics in geochemistry. This encompasses, for instance, the long-term carbon cycle, pedogenesis, element cycles associated with the development of surface ecosystems and deep biosphere. Chemical alteration results from a disequilibrium of the constituent mineral phases with their reactive environment, controlled in large part by in situ physico-chemical conditions, which can include microbial activity, plant metabolism and human activities. It proceeds through an array of biotic and abiotic mechanisms that leave behind their imprints at mineral surfaces or in the fluid phase. Such signatures can be measured in experiments or observed in the geological record, and can be used to monitor biogeochemical processes and better understand underlying mechanisms.

This session invites contributions concerned with processes associated with the chemical weathering of minerals, where the unifying theme is the identification and measurement of geochemical alteration signatures. This includes – but is not limited to – (1) the study of the stoichiometry of elemental release and/or the use of isotope measurements, with respect to the parent material and the surrounding fluids and organisms, (2) the structural and chemical characterization of mineral near-surface evolution occurring during weathering (such as the mineralogy of secondary phases, etch pits, or surface altered layer formation), and (3) the study of microbial communities associated with specific reactions involving mineral interfaces. Contributions focusing on methodologies or analytical tools directed at better characterizing fluid-mineral-microorganism interfaces are welcomed. Contributions from early career scientists are also particularly encouraged.

Recent advances in analytical techniques and modeling have opened the door to new applications of tracers in hydrology, oceanography, ice core science, environmental studies, and at interfaces between the hydrosphere and other parts of the Earth system. For example, new portable and field operable devices now provide unprecedented insight into temporal variability of fluids and of important processes in hydrology in real time; tracer-enabled forward and inverse models provide deeper insight into natural tracer variance in space and time and create new opportunities for data-model evaluation; lab-based analytical advances have reduced sample-size requirements thereby increasing the potential reach of inert noble gas radionuclides (³⁹Ar, ⁸⁵Kr, ⁸¹Kr) to date a wide range of environmental samples; and new techniques to precisely measure rare isotopes in fluids (e.g., clumped O₂, N₂, CH₄, ¹⁷O, and noble gas isotopes) provide quantitative constraints about sources and processes. These advances have led to progress in groundwater hydrology, chemical oceanography, environmental research, paleoclimate, limnology, atmospheric chemistry, volcanology, and other fields.

This session invites contributions on novel applications involving tracers in water – groundwater, rivers, lakes, oceans, ice, and other fluids – or at the interfaces between water and the solid Earth or atmosphere. Contributions involving novel analytical techniques and / or tracer-enabled modeling (e.g., ranging from idealized box models to real-time updated groundwater models to GCMs) are encouraged.

Earth’s geologic past captures various geochemical states of the ocean-land-atmosphere system. The study of geochemical processes in the past informs our understanding of modern cycles and how they will be affected by modern climate change. Importantly, these geochemical cycles form key feedbacks within the climate system, thus controlling the impact of perturbations over multiple timescales. Modelling fills important gaps left by the incomplete geological record and allows us to assess proxy limitations and uncertainties. In this session, we invite work on terrestrial, marine or atmospheric geochemical modelling across all spatial and temporal scales for the geological past, using models of various complexities (from 1-box to Earth System models). We particularly welcome submissions on element-specific cycling under background and/or perturbed climate conditions, processes within the critical zone and linking it to the marine realm, and on geochemically-driven feedbacks within the climate system.

Reactive transport modeling has reached a high level of maturity and might even be recognized as a distinct field within the Earth and environmental sciences, as it is often noted as a key expertise of its practitioners. Complex and coupled behavior has been explained in many environments with increasing fidelity in the process representation. It is however clear that many challenges remain. Arguably a significant challenge is associated with the range of length scales, from the molecular to nanoscale to pore scale up to the watershed and continental scales. Further, in each scale and environment, coupling to all relevant processes must be considered. For example, in charged porous media, ion mobility is strongly affected by electrostatic interactions and off-diagonal coupling effects. In the Earth’s critical zone, gas transport, sediment erosion and burial, microorganisms, and plants all play a role but are rarely considered simultaneously in computational models. At the watershed scale, the interactions between different Earth compartments, including subsurface and surface water, vegetation, and the atmosphere affect the reactive processes that typically play out in highly heterogeneous and transient settings. In this session, we invite contributions that address these challenges, with applications in, but not limited to, biogeochemical cycling, contaminant transport, radioactive waste disposal, CO₂ sequestration, pedogenesis, chemical weathering, and retention and release of water, nutrients and metals from watersheds. We encourage submissions that include experimental or field studies and have a focus on new modeling and computational approaches that chart the future of reactive transport.

More than one third of the Earth's land surface is arid or semi-arid, supporting ~20% of the world's population. These environments are characterized by slow rates of soil formation and scarcity of water, which impact (bio-)geochemical processes at all scales. However, our understanding of weathering processes, hydro-geochemical changes in the critical zone, and soil-microbial-plant interactions in these environments is still limited,. These knowledge gaps restricting our ability to assess their response to increased anthropogenic impacts and global warming effects.

This session welcomes contributions on all types of (Bio-)geochemical processes occurring in the critical zone of arid and semi-arid environments. Presentations are invited on a variety of topics, including carbon fluxes and sequestration in arid areas, weathering processes, water availability impact on geochemical processes and concomitant effects on biota and agriculture, the contamination and remediation of arid soil and water resources.

Carbon cycle processes operate over a vast range of different timescales. Long-term carbon cycle, responsible for keeping Earth within a habitable temperature range for life to exist, is regulated by the balance between carbon inputs from the lithosphere, and carbon outputs via chemical weathering and organic carbon burial. Shorter-term carbon cycling, on the other hand, is responsible for modulating the distribution of carbon between Earth’s ocean and atmosphere. Reconciling the interactions between the processes that comprise the carbon cycle is not only key to understanding past climatic changes, but also for predicting the efficacy of future enhanced carbon dioxide removal strategies. Lithology, tectonic uplift, reaction rate, climate, sources of acidity, and biology, are all variables which control the timescales over which chemical weathering, and hence, carbon cycling occurs.

This session aims to bring together researchers from a range of disciplines that seek to quantify and understand surficial processes and the carbon cycle at various timescales, and their possible relations with mountain uplift. The session includes tectonic evolution, weathering, erosion, the carbon cycle, hydrological cycles, climate changes and isotopic tracing from modern days to deep time. Submissions from studies that incorporate field data, laboratory experiments, numerical modeling, chemical and isotopic tracers, and/or theoretical development are encouraged in the context of natural weathering studies or geoengineering efforts such as (e.g. enhanced weathering).

Weathering and erosion are the key processes that shape Earth’s landscape, regulate atmospheric CO2, and control the delivery of sediments and solutes to the ocean, affecting global climate over geological time scales. Meanwhile, temperature, precipitation, and physical erosion are linked to tectonic uplift and are critical factors influencing weathering. These interactions imply that natural or anthropogenic perturbations of landscapes can have substantial impacts on biogeochemical cycles across Earth’s surface. Understanding the interactions of physical and chemical mass fluxes allows us to use sedimentary archives to reconstruct biogeochemical cycles across the geologic past and to predict, or perhaps even steer the carbon cycle of the future.

We welcome field, laboratory, and/or modeling studies that explore the fundamental controls and interactions between tectonics, climate change, weathering, and erosion using sediment records or dissolved loads. These studies can range from regional to global in scope and explore processes at temporal scales spanning from seasonal to tectonic.

NOTE: This live event includes sessions 9hO3 and 9jO1, in that order, with no break between them.

Earth's cold regions, including high alpine, glaciated, periglacial, sea-ice, and permafrost areas, are subject to a set of geochemical processes influenced by ice and snowmelt, freeze-thaw cycles, and biological dynamics unique to cold environments. From the organic matter stored in permafrost, to iron cycling in glacial fjords, to microbially mediated oxidation of sulfur in subglacial environments, cold regions play a distinct and important role in Earth’s broader geochemical cycles. These processes relate to a complex set of feedbacks, and are likely to play an important role both in Earth’s past ice ages and in the global impacts of a changing cryosphere under a changing climate.

This session will feature presentations that advance our understanding of cold regions’ hydro-, bio-, and geochemistry, their past evolution, and their response to climate warming and land use change. This session broadly seeks to integrate any number of settings and methods of geochemical analysis, including hydrochemical, isotope tracer, (micro-)biological, and mineralogical approaches. Contemporary observations and inferences from the geological record are both solicited. By bridging timescales and approaches, the session aims to provide a comprehensive look at the consequences of cold regions geochemical processes for the Earth system.

Earth’s surface is the crucial intersection of rock, soil, water, air, and living organisms that sustains life. Chemical weathering and physical erosion are among the key Critical Zone processes that redistribute mass and energy, govern ecosystem structure, and stabilize global climate. Characterizing and quantifying these dynamic processes through space and time require a combination of data that include sophisticated tracers and proxies and physically and chemically based models. This session welcomes contributions on the development and application of novel and traditional biogeochemical proxies and modeling approaches, including field and laboratory studies. Of particular interest are interdisciplinary studies that aim to better understand complex relationships between human activity, climate, erosion, weathering, and the hydrological cycle. We invite submissions from researchers of all experience levels and backgrounds, but especially encourage submissions from early career researchers and those from backgrounds typically underrepresented in the Earth Sciences.

NOTE: This live event includes sessions 9hO3 and 9jO1, in that order, with no break between them.

The impacts of climate change on landscape-scale environmental processes are particularly exacerbated in high latitude systems across the World. Understanding how high latitude systems are changing is key to assessing dynamic ecosystem responses to an altered climate. Additionally, research into defining biogeochemical signatures with respect to key environmental factors is equally important, particularly when faced with highly heterogeneous systems like high latitude environments. Ecosystem responses to an altered climate regime may be far-sweeping across multiple scales (micro- to macro-scale) and encompass many interdisciplinary research topics, including soils, minerals, microbes, vegetation, snow, and aqueous systems.

This session will focus on the topic of biogeochemistry in any high latitude system with a particular focus on the critical zone. This may include arctic and sub-arctic aqueous environments, permafrost regimes or soils that experience regular freeze-thaw cycles, fire-affected regions, snow and vegetation dynamics, soil-microbial-plant interactions, and actively thawing areas in the North. We invite presentations that focus on field, laboratory, and modeling studies and highly encourage cross-disciplinary efforts. With this session, we seek to establish a better understanding of how high latitude biogeochemistry is evolving with rapidly changing climactic factors and facilitate discussions on future focus areas.

Water movement in the Critical Zone drives biogeochemical reactions, controlling water quality, supplying nutrients to the biosphere, and transforming bedrock to regolith and soils. The products of these water-rock-life interactions dissolved in streams and rivers integrate and reflect different water flow paths and transit times within watersheds. Under a changing climate, local and global hydrological systems are subject to more extreme perturbations, subsequently impacting Critical Zone functioning and evolution. Therefore, an understanding of the mechanisms that generate and affect the coupled dynamics of hydrological and biogeochemical fluxes in the Critical Zone is required across a multitude of spatial and temporal scales. This session particularly welcomes contributions that employ interdisciplinary approaches such as the combination of hydrological and biogeochemical observations and modeling (including concentration-discharge analyses), the use of conservative and reactive tracers, and coupled lab-field approaches. We invite submissions from researchers of all experience levels and backgrounds, but especially encourage submissions from early-career researchers and those from backgrounds typically underrepresented in Earth Sciences.

In the Earth’s cold regions, accelerating climate change and intensifying human activities are increasingly impacting (near-)surface hydro(geo)logical cycles and associated water quality, soil health, and ecosystem functions. Varying surface temperature, snowmelt, and precipitation during the winter and shoulder seasons are altering the annual evapo(transpi)ration, the magnitude and timing of surface runoff, soil freeze-thaw cycles, soil temperature regimes, and groundwater recharge and discharge in both alpine and circumpolar watersheds. Hydrogeochemical changes in the vadose zone and underlying aquifers include, among others, the increase in total dissolved solids, the production of greenhouse gases, and the mobilization of geogenic contaminants. These changes not only drive hydrochemical variations in the receiving surface waters and groundwater-dependent ecosystems, but also create new risks to the drinking water and food supplies in cold regions. The expansion of temperate climate zones at the expense of colder areas also facilitates agricultural expansion, urban growth, and natural resources exploitation, further adding to the anthropogenic pressures on the cold regions’ water and soil resources. A foundational question to be answered is how, and how fast, hydrogeochemical and the interlinked biogeochemical processes in our planet’s cold regions are responding to the intensifying agents of environmental change, at the local and regional scales. This session will feature presentations that advance our understanding of cold regions’ hydrogeochemistry and biogeochemistry, and their resilience to climate warming and land use change. Theoretical, field, laboratory, modeling, and integrated studies addressing processes in groundwater, surface waters, and soils are all welcome.

Earth's cold regions, including high alpine, glaciated, periglacial, sea-ice, and permafrost areas, are subject to a set of geochemical processes influenced by ice and snowmelt, freeze-thaw cycles, and biological dynamics unique to cold environments. From the organic matter stored in permafrost, to iron cycling in glacial fjords, to microbially mediated oxidation of sulfur in subglacial environments, cold regions play a distinct and important role in Earth’s broader geochemical cycles. These processes relate to a complex set of feedbacks, and are likely to play an important role both in Earth’s past ice ages and in the global impacts of a changing cryosphere under a changing climate.

This session will feature presentations that advance our understanding of cold regions’ hydro-, bio-, and geochemistry, their past evolution, and their response to climate warming and land use change. This session broadly seeks to integrate any number of settings and methods of geochemical analysis, including hydrochemical, isotope tracer, (micro-)biological, and mineralogical approaches. Contemporary observations and inferences from the geological record are both solicited. By bridging timescales and approaches, the session aims to provide a comprehensive look at the consequences of cold regions geochemical processes for the Earth system.

As highlighted in the latest IPCC report, carbon dioxide removal (CDR) is required to reach net zero CO₂ emissions and keep global warming well below 2°C, as agreed at COP21 in Paris. Global efforts are currently undertaken to explore negative emission technologies (NETs). A promising NET is enhanced weathering (EW) of ground minerals, either on land or in the ocean, in the latter case referred to as ocean alkalinity enhancement (OAE). The weathering of these minerals raises alkalinity and thereby enhances the CO₂ sequestration from the atmosphere to the soil/ocean.

As promising this technique appears in modeling approaches, several fundamental questions remain, such as the quantification of CO₂ sequestration in the field, the dissolution kinetics with respect to mineral saturation states and precipitation processes, the deployment strategy (e.g. solid versus previously dissolved), interactions with soil biota and soil organic carbon, the impact on ecosystems and biodiversity as well as socio-economic and ethical implications. 

In this session, we welcome all contributions tackling one or more of the current EW and OAE challenges; including experiments, field and modeling studies as well as studies working on monitoring, reporting and verification (MRV) strategies.

This session is intended to bring scientists from different disciplines together to enhance our understanding of biogeochemical processes, their ecological impact as well as deployment strategies.

Earth's cold regions, including high alpine, glaciated, periglacial, sea-ice, and permafrost areas, are subject to a set of geochemical processes especially influenced by ice. From the organic matter stored in permafrost, to iron cycling in glacial fjords, to microbially mediated oxidation of sulfur in subglacial environments, cold regions play a distinct and important role in Earth’s broader geochemical cycles. These processes relate to a complex set of feedbacks, and are likely to play an important role both in Earth’s past ice ages and in the global impacts of a changing cryosphere under a changing climate.

This session broadly seeks to integrate any number of settings and methods of geochemical analysis, including hydrochemical, isotope tracer, microbiological, and mineralogical approaches. Contemporary observations and inferences from the geological record are both solicited. By bridging timescales and approaches, the session aims to provide a comprehensive look at the consequences of cold regions geochemical processes for the Earth system.

From actively eroding mountains to sedimentary basins, chemical weathering and mobilization of organic carbon is intimately linked to physical processes of erosion, transport, and deposition of sediment. These links are thought to govern Earth’s climate evolution, and they imply that natural or anthropogenic perturbations of landscapes can have substantial impacts on biogeochemical cycles across Earth’s surface. Understanding the interactions of physical and chemical mass fluxes allows us to use sedimentary archives to reconstruct biogeochemical cycles across the geologic past and to predict, or perhaps even steer the carbon cycle of the future.

Because both physical and chemical mass fluxes are highly variable in space and in time, many methodological and conceptual challenges remain in (1) measuring rates of physical and chemical mobilization of different minerals and organic matter; (2) modeling feedbacks between denudation, carbon cycling, climate, and landscape evolution; (3) bridging gaps between laboratory, local, regional, and global scale studies; and (4) linking theory built on modern-day observations to the interpretation of archives for Earth’s past biogeochemical cycles.

Here, we invite field, laboratory, and modeling studies that investigate links between physical and chemical mass fluxes across Earth’s surface and their impacts on biogeochemical cycles and Earth’s climate. We also welcome contributions that develop or refine tools and proxies to investigate these links over geologic timescales.

Northern latitudes of Pakistan are warming at faster rate as compared to the rest of thecountry. It has induced irregular and sudden glacier fluctuations leading to the progression of gla-cial lakes, and thus enhancing the risk of Glacier Lake Outbursts Floods (GLOF) in the mountain systems of Pakistan. Lack of up-to-date inventory, classification, and susceptibility profiles of glaciernlakes and newly formed GLOFs, are few factors which pose huge hindrance towards disaster pre-paredness and risk reduction strategies in Pakistan. This study aims to bridge the existing gap indata and knowledge by exploiting satellite observations, and efforts are made to compile and up-date glacier lake inventories. GLOF susceptibility assessment is evaluated by using Analytical Hi-erarchy Process (AHP), a multicriteria structured technique based on three susceptibility contrib-uting factors: Geographic, topographic, and climatic. A total of 294 glacial lakes are delineated witha total area of 7.85 ± 0.31 km2 for the year 2018. Analysis has identified six glacier lakes as potential GLOF and met the pre-established criteria of damaging GLOFs. The historical background of earlier GLOF events is utilized to validate the anticipated approach and found this method appropriate for first order detection and prioritization of potential GLOFs in Northern Pakistan.

Earth’s surface is the crucial intersection of rock, soil, water, air, and living organisms that sustains life. Chemical weathering, physical erosion and other processes redistribute mass and energy, govern ecosystem structure, and stabilize global climate through time. This session aims to bring together all applications of novel geochemical tools, from elemental analyses to metal(loid) stable and radiogenic isotopes (Li to U), to solve problems concerning mechanisms, feedbacks and rates of modern or past Earth surface processes. We encourage submissions that apply novel geochemical tools to erosion, weathering, sediment transport (provenance, residence time, recycling, etc.), ecosystem functioning, or other processes across all components of the present-day Earth’s surface, or as recorded in sediment archives. Of particular interest are contributions that quantitatively disclose complex relationships among human activity, climate, erosion and weathering over short timescales. We also encourage submissions which share new analytical methods, which refine existing and underexplored geochemical tools and proxies, or those which use theory or modelling to improve the interpretative ability of these tools. We sincerely invite scientists at any career stage to contribute to this session.

The transfer of sediment, solutes, and carbon from upland sources to marine sinks play an important role across a range of Earth systems. Earth’s surface is the critical interface across which the bulk of chemical and biological exchanges take place. Most cycles in Earth’s surface involve the transport of material by fluids, either in dissolved form or as particles. The deep understanding of individual processes, and the connections between them are important to advance our knowledge of how Earth’s surface operates, responds to and/or influences climate variations. In this session, we encourage research that explores the fundamental controls and coupling of various aspects of sediment transport from source to sink, and/or weathering history across disciplines, scales, and systems.

Including but not limited to:

1) Source to sink systems of sedimentary processes, transport dynamics and/or mechanisms (e.g. large river catchment, small mountain river catchment), and sediments provenance analysis methods.

2) Quantification and understanding of modern weathering regimes, with an emphasis on the effect of sedimentary cycles on chemical weathering, and on the extraction of continental weathering signals from sedimentary basins.

3) Connections between weathering and climate change on various timescales (e.g., glacial-interglacial cycles of the late Pleistocene, long-term changes over the Cenozoic) and how these changes are being constrained from geologic records.

More than one third of the Earth's land surface is arid or semi-arid, supporting ~20% of the world's population. Agricultural, Industrial, and other human activities put the soils and water resources of these environments under high risk of degradation and contamination. These environments are characterized by slow rates of soil formation and scarcity of water, which dictates the characteristic and rates of natural remediation processes.  However, our understanding of soil and water contamination and degradation processes in these environments is still limited, restricting our ability to assess long-term effects and remediate of the affected soil and water resources. Transport, chemical transformations, and disintegration of organic and inorganic contaminants, in dry environments, are widely studied, yet are far from being fully understood. In this session, it is proposed to discuss different aspects of soil and water degradation and contamination processes, at arid and semi-arid environments. Basic and applied sciences works associated to these topics, including remediation of soil and water resources, are encouraged to be presented in the session. Both natural and human induced processes are welcome to be discussed, in all physical, chemical, and biological aspects.

Weathering and erosion are the key processes that shape Earth’s landscape, regulate atmospheric CO₂, and control the delivery of sediments and solutes to the ocean, affecting global climate over geological time scales. Meanwhile, temperature, precipitation, and physical erosion which are linked to tectonic uplift are critical factors influencing weathering. Progressive uplift of the Himalaya-Tibetan Plateau (HTP) forced the reorganization of the great rivers of Asia and in part drove the intensification of the Asian monsoon system. Together these processes have formed the largest sediment source-sink system in the world. The uplift-weathering hypothesis suggested that increased erosion and then chemical weathering of HTP rocks and the resultant consumption of atmospheric CO₂ was a major cause of Cenozoic cooling. However, how the rate of silicate weathering in Asia evolved through the late Cenozoic is still debated and the role of silicate weathering versus organic carbon burial in driving Cenozoic cooling remains unresolved. Moreover, the additional weathering of sediments deposited in the middle and lower reaches of large river basins with relatively low-relief has been largely neglected and its potential effect as a negative feedback in the geological past remains unclear. In this session, we focus on the various Asian sediment source-sink systems from high mountains to the marginal seas, which may have influenced the global weathering budget during the Cenozoic. We welcome contributions addressing the interactions between tectonics, climate change, weathering and erosion using sediment records or dissolved loads from both Asia and its marginal seas spanning tectonic to seasonal time scales.

The earth’s climate is regulated by a range of geochemical processes on Earth’s surface including the physical erosion, chemical weathering, organic carbon oxidation and burial. Previous studies have shown that Cenozoic tectonic uplift enhanced surficial erosion and weathering, and influenced the carbon cycle processes. However, the link is challenged by a growing body of evidence from the field observations, sediment achieves and modelling. . This session aims to bring together researchers from a range of disciplines that seek to quantify and understand surficial processes and the carbon cycle at various timescales, and their possible relations with mountain uplift. The session includes tectonic evolution, weathering, erosion, the carbon cycle, hydrological cycles, climate changes and isotopic tracing from modern days to deep time. Studies incorporating lab and modern field observations, insights from geological archives, new proxies and model simulations are all welcome. We encourage submissions from early career researchers and interdisciplinary studies that help to in-depth understanding of the Earth’s surface processes.

Carbon cycle processes operate over a vast range of different timescales. The long-term carbon cycle, responsible for keeping Earth within a habitable temperature range for life to exist, is regulated by the balance between carbon inputs from the lithosphere, and carbon outputs via chemical weathering and organic carbon burial. Shorter-term carbon cycling, on the other hand, is responsible for modulating the distribution of carbon between Earth’s ocean and atmosphere. Reconciling the interactions between the processes that comprise the carbon cycle is not only key to understanding past climatic changes, but also for predicting the efficacy of future enhanced carbon dioxide removal strategies.

Lithology, tectonic uplift, reaction rate, climate, sources of acidity, and biology, are all variables which control the timescales over which chemical weathering, and hence, carbon cycling occurs. Spatio-temporal variations in these parameters impact quantitative estimates of the magnitudes of sources and sinks of atmospheric carbon over 1,000 - 1,000,000 year timescales.

This session aims to bring together researchers working on various aspects of the carbon cycle, to bridge the knowledge gaps between chemical weathering, climate, and tectonics. This will provide a 21^st century view of the carbon cycle which is of paramount importance to future geoengineering efforts to combat anthropogenic climate change. We particularly encourage submissions from studies that incorporate field data, laboratory experiments, numerical modelling, chemical and isotopic tracers, and theoretical development. This could be in the context of natural weathering studies or geoengineering efforts such as (e.g. enhanced weathering).

Weathering of primary minerals in soils and sediments results in carbon sequestration. This process is gaining more attention due to pressure of the climate change on environment and humanity. While weathering can be an abiotic process, it is enhanced by presence of biota, both microorganisms and higher plants. Weathering processes are promoted by availability of water, but arid and semiarid soils also contribute to atmospheric carbon capturing and globally are important sink for inorganic carbon. They constitute 30% of total landmass and increasing percent of global soils are becoming seasonally dry because of climate change. This session will concentrate on natural and anthropogenic carbon sequestration through weathering with focus on arid and semi-arid systems. Presentations are invited on a variety of topics, including global distribution and contribution of arid and semiarid land to carbon sequestration, new techniques used to measure and understand fluxes of CO₂ and water in arid soils, how water availability and type and complexity of plant cover influence weathering and carbon sequestration, how agricultural practices can impact carbon sequestration in soils with particular focus on arid and seasonally dry lands. These marginal lands also support diverse ecosystems and large percentage of global populations lives in areas that are impacted, therefore understanding their behavior and management has environmental, economic, and social implications.

Sulfur is an essential element of life as we know it. The oxidation and reduction of sulfur species (S^2-, S_n^2-, S⁰, S₂O₃^2-, SO₃^2-, SO₄^2-) is primarily driven by microbial activities on the Earth’s (sub)surface. The biogeochemical cycling of sulfur is intimately tied to other elements such as C, Fe, N and various nutrients, metals and contaminants, making them relevant for biological and geological evolution, origin of life, biosignatures, greenhouse gas emissions, environmental bioremediation, pollutant attenuation and the development of sustainable materials for green energy of the future. In this session, we invite contributions that highlight recent advances and ideas in this area. We particularly seek interdisciplinary approaches, such as those that attempt to link ‘omics techniques to microbial cultivation, nano-scale processes to global implications, and modern analogues to the geological record.

NOTE: This live event includes sessions 10aO1 and 13bO1, in that order, with no break between them.

Phosphorus is an essential nutrient; feedbacks between dynamic environmental conditions and phosphorus biogeochemical cycling have profoundly influenced the evolution of life on Earth. Furthermore, a key research and management objective is to evaluate the response of aquatic P cycling to human-induced environmental changes such as deoxygenation and eutrophication. Particularly in freshwater and coastal systems, perturbation of the P cycle is central in water-quality issues and loss of ecosystem services. Probing the linkages between the biogeochemical cycle of phosphorus and cycles of other elements such as oxygen, carbon, sulfur and redox-sensitive (trace) metals remains challenging. However, driven by advances in analytical capabilities and modelling, we are currently transforming our understanding of the functioning and evolution of the aquatic phosphorus cycle. This session aims to bring together researchers who contribute to our increasing understanding of phosphorus cycling in marine and terrestrial aquatic systems, through (integration of) field observations, experimental biogeochemistry and computational tools. We welcome contributions across the geological timescale from ancient to modern, as insights from well-constrained modern systems inform paleo-reconstructions. We are also very much interested in innovative field studies, novel analytical approaches and exploration of the coupling between water-column and sedimentary processes.

NOTE: This live event includes sessions 12aO3 and 10bO1, in that order, with no break between them.

Methane production, transport, and oxidation across the sediment-water column-atmosphere system have a significant role in Earth’s carbon budget and biogeochemical cycling. These processes induce unique geosphere-biosphere interactions that can influence the biogeochemical cycling of elements and climate system. From a climate perspective, about a quarter of postindustrial global warming is attributed to methane gas, and aquatic ecosystems are estimated to contribute up to 50% of current global methane emissions. From a biogeochemistry perspective, methane cycling in aquatic and sedimentary environments is recognized to have a profound impact on microbial ecology and elemental cycling over a wide spatio-temporal scale. Furthermore, the detection of methane in planetary bodies beyond Earth provides a critical juncture in expanding our understanding of methane biogeochemistry to astrobiology studies.

This session invites contributions on biogeochemistry of methane cycling in diverse aquatic and sedimentary environments. Studies pertaining to the geology, biology, chemistry, and physical parameters contributing to methane production, their reservoirs, and fluxes through the sediment-water column-atmosphere systems in various environmental settings (e.g., oceans, inland waters, terrestrial environments, planetary bodies) are invited. Paleo-perspective based on sediment records as well as present and future perspectives on the role of anthropogenic impact and climate change on methane dynamics, are also invited.

Organo-mineral interactions exert control over the fate and function of a diverse suite of biomolecules. For instance, mineral surfaces can stabilize biomolecules (e.g. preservation of ancient and environmental DNA) or catalyze their further transformation (e.g. oligomerization of nucleic acids in early earth systems). On the other hand, biomolecule (e.g. secondary metabolites) interactions with mineral surfaces can also result in mineral transformations. Elucidating geochemical mechanisms that control these interactions at mineral surfaces is essential to unravel the role of biomolecules in influencing biogeochemical cycles and biomolecule stability or transformation in terrestrial and extraterrestrial environments. Understanding such processes is critical to advance our knowledge on biomarker preservation, the persistence of ancient and environmental DNA, mineral facilitated horizontal gene transfer, biofilm formation, wastewater-based epidemiology, and extraterrestrial biosignatures. In addition, understanding the role of mineral surfaces in catalyzing the transformation of biomolecules may provide new insights into the origin of life.

This session seeks to bring together studies on the mechanistic understanding of mineral surface interactions in the context of biomolecule behavior, function, and fate in terrestrial and extraterrestrial systems, both past and present. We encourage experimental studies based on field- and laboratory setups as well as theoretical and modeling-based studies.

Microbial communities play a central role in carbon cycling, which can influence biogeochemical cycles and shape the evolution of the biosphere. These processes occur at multiple scales, from the building and breaking of organic compounds, both natural and manmade, to modulating atmospheric O₂ and CO₂ levels across geologic time. They also operate in all ecosystems, from terrestrial and deep subsurface environments, to coastal habitats, through to the global ocean. Constraining how microorganisms interact with their environment and each other to mediate transformations of inorganic and organic carbon, either directly (metabolic interactions) or indirectly (ecological interactions) is, therefore, central to reconstructing biogeochemical dynamics in the Earth system. Insight emerging from both contemporary and paleo studies, however, reveal that microbial carbon cycling is highly complex, making the broad scale environmental impacts difficult to assess.

Here we seek contributions that link dynamics in microbial carbon cycling to the response of Earth-life-climate system. In particular we welcome submission of multidisciplinary studies from all ecosystem types both modern and ancient, from the continents to the oceans, and anything in between. We encourage contributions that employ multiple 'omics approaches, applications of organic and inorganic geochemistry, microbiology, chemical and biological oceanography, experimental and analytical isotope geochemistry, and modelling.

Biosignatures are substances, patterns, or objects that serve as evidence of life, past (fossilized) or present (active), on Earth and potentially other habitable worlds. Significant research has been conducted to identify a diverse set of biosignatures, including molecules (e.g. pigments, lipids), morphologies, biofabrics, elemental/isotopic compositions, fossils, and minerals. Similarly, ongoing efforts seek to identify sedimentary and igneous depositional environments that may effectively preserve biosignatures through geologic time. This field is interdisciplinary and rapidly expanding. For instance, the effects of microbial activity on the formation of fossils is an emerging area: fossilization of the quality we know is probably not possible without the involvement of microorganisms, a fact that unites mineralogy, paleontology, and geomicrobiology. A wide variety of tools and techniques have been developed to identify and interpret modern and ancient biosignatures in the field with in situ analysis. Furthermore, laboratory analog research has advanced the understanding of how biosignatures are preserved or degraded over time, especially in extreme environments.

We invite contributions from all fields that investigate the connection between microorganisms and their (paleo)environments, including efforts on in situ and remote detection of biosignatures, their synthesis and analysis, and potential synthesis in prebiotic systems. Submissions highlighting novel analytical, experimental, and modeling approaches are encouraged. This session is explicitly open to multi-discipline approaches that incorporate methods coming from different branches of science.

The Earth’s geosphere and biosphere have coevolved almost since the planet took shape approximately 4.55 billion years ago. Over this vast geological time, microbial life has evolved numerous biochemical pathways for coupling redox transformations of metals and non-metals to metabolism. These pathways not only underpin bioenergetic and biosynthetic requirements of microorganisms, but also profoundly influence and expedite the evolution of Earth and its biota. For example, many bacteria and archaea obtain energy and electrons from redox reactions of metals, non-metals, metalloids, actinides, etc., which on the other hand can also be incorporated into active sites of proteins (enzymes) (e.g., Fe, Co, Ni, Zn, Mo, W, V, Cu, etc.) to form their core catalytic centers. As a consequence, the environmental (ecological) dynamics of these elements (speciation, distribution, transport, etc.) have been changing continuously through geologic time. In the Anthropocene, some metals and metalloids have undergone a greatly enhanced pace of (re)mobilization (e.g., Hg, Se, Zn, Li, As, Co, Cr, Cu, Fe, Mn, U), with a resulting increase in toxicity to the biota. This session invites presentations on both dissimilatory and assimilatory metabolisms involving redox inorganic transformations with major implications for biogeochemical cycling, ecosystem functionality, and planetary health. We welcome submissions that aim to explore the bi-directional relationships that exist between nutrient and trace element availability/speciation and biodiversity/metabolism, particularly from a co-evolutionary perspective.

The importance of bacterial activity in the formation of fossils is becoming more obvious over the course of the last years. Without the help of microbes the physico-chemical obstacles, like pH, Eh and kinetic effects, would be improbable to overcome for fossilization reactions alone. Especially extraordinary preserved fossils and soft tissue fossilization are probably not possible without microbial activity. There are numerous working groups involved in deciphering the interplay between microorganisms and the abiotic environment that will in the end produce the spectacular fossils we are used to see for decades now. The emergence of new analytical techniques and advances in sequencing technology lead to a new understanding of these complex connections. Additionally the understanding of biofilm-mineral reactions is an emerging field.

In this session, we invite contributions from all researchers that investigate the connection between the microbial and geological world either analytically or experimentally. It is explicitly open to multi-discipline approaches that do incorporate methods coming from different branches of science. We encourage paleontologists, microbiologists, taphonomists, petrologists and geochemists that work with or about microorganisms and fossilization to submit an abstract. This session intends to provide a platform for the exchange between the different fields mentioned above.

This session is part of DFG (German Research Foundation) Research Unit 2685 “The Limits of the Fossil Record: Analytical and Experimental Approaches to Fossilization”.

Earth’s geosphere and biosphere have coevolved over time, influencing each other’s trajectory for most of its 4.55 billion years of history. Biogeochemical cycles play a key role in controlling this interaction, connecting long-term geological cycles and the much faster evolution of the biosphere. Microbial-encoded proteins containing redox-sensitive transition metals as their core catalytic center carry out the majority of the key biogeochemical reactions. Metals such as Fe, Co, Ni, Zn, Mo, W, V, and Cu are used in these proteins to access diverse redox couples. While these trace metals play a key role in providing life with critical cofactors, their environmental availability has changed through deep time as a result of complex geosphere-biosphere interactions. We invite contributions from diverse disciplines exploring the role of trace element availability in controlling microbial diversity and biogeochemistry in extant ecosystems as well as through deep time, as well as the geological and biological processes controlling their delivery and availability on the surface of the planet. 

Reconstructing microbial life through our planet’s long history or identifying potential signs of microbial life elsewhere in the universe are challenges in geobiology and astrobiology research. Our knowledge about the distribution and diversity of microbial life through time and space is still limited, and the extent of habitability in “extreme” environments is still poorly constrained. These challenges are attributed, in part, to the vast diversity of metabolisms, the enormous complexity of biological communities, microbe-mineral interactions, the great variety of potential habitats, and the dynamics of biological and planetary processes across temporal and spatial scales. An additional level of uncertainty is the unambiguous identification and interpretation of chemical or structural indicators that serve as “fingerprints” or “biosignatures”. Spectroscopic techniques and high-resolution imaging at the cellular to nanometer-scale has revolutionized our current understanding of biosignatures including structural microfossils, biogenic minerals, or molecular compounds. This session aims to bring together contributions that cover the formation, preservation, and/or application of biosignatures that provide inferences about ancient or modern biogeochemical processes. We invite presentations that focus on field- or laboratory-based approaches, studies focusing on biomineralization or biogeochemical cycling in Earth’s past or present day environments, as well as co-evolution of microbial life over geologic time.

The vast majority of microbes on Earth are currently not cultured and are often referred to as microbial dark matter. Due to the inability to study these microbes in pure culture, we lack knowledge of their physiological capabilities. Understanding their metabolic functioning is the key to recognizing their role in biogeochemical cycling. In marine habitats such as sediments or hydrothermal vent systems up to 99% of Bacteria and Archaea have not been cultured under laboratory conditions. Sequencing of metagenomes and single annotated genomes has given us vital information on potential metabolisms of uncultured representatives. Although bioinformatic tools have advanced considerably, another difficulty when working with genomic information is that a very large proportion of genes encoded on the genomes cannot be allocated to a function. Since uncultured microbes encompass such a large proportion of the microbial communities, it is vital to understand what chemical reactions they can catalyze, what the genes are that encode these respective enzymes, and what environmental conditions trigger their respective activities. Besides advancing our comprehension of the role the uncultured microbial majority plays in biogeochemical cycling, this knowledge is also fundamental to predicting their behavior in future climate change scenarios.

This session combines a variety of approaches used that will advance our understanding of the role that uncultured microbes play in the environment for bio-geo-coupling processes. This includes sequence-based analyses, function-based screening for novel enzymes, cultivation-based techniques, incubation and isotope experiments, which link metabolic activity to the uncultured microbes.

Mercury is an element with both geogenic sources implying ancient evolutionary interactions with microbes, and anthropogenic sources leading to strong participation by microbes in environmental contamination/detoxification. Recent years have seen major advances in our understanding of the geomicrobiology of mercury. Some of these recent advances include phylogenetic insights into the evolution and distribution of mer and hgc genes, nanoscale elucidation of factors influencing the speciation of Hg during cellular uptake, and the development of new multi-omics approaches to unraveling of microbial Hg transformations. Yet the origins and mechanisms of many microbe-mercury interactions remain unclear. This session aims to bring together submissions on these and related topics, to explore our contemporary knowledge base on the geomicrobiology of mercury.

Through the history of life on Earth, microorganisms have evolved several biochemical contrivances to utilize redox transformations of inorganic substances for their bioenergetic as well as biosynthetic requirements. While many microorganisms are known to obtain and transduce energy from redox reactions involving ions of non-metals, metals, metalloids, actinides, etc., minerals and other naturally occurring inorganic substances are also utilized via redox biochemical processes as the sources of the trace elements which are essential parts of a host of vital biomacromolecules. In the context of an ecological system (biome), many of these inorganic biochemical processes, whether dissimilatory or assimilatory from the microbes’ perspectives, become the major drivers of in situ biogeochemical cycles, which, besides the electron transfer reactions, include the dissolution, immobilization and mineralization dynamics of the elements concerned. In the process of governing chemical speciation within biogeochemical systems, redox metabolisms also control the sequestration, transport, distribution, and thereby the bioavailability, ecophysiological toxicity, bioremediation, and recovery of a wide range of elements, whether copious or scarce in the environment (examples include As, C, Co, Cr, Cu, Fe, Hg, Mn, N, P, S, Se, Sb, Tc, and U). This session of Goldschmidt 2023 would discuss and highlight all recent advances in our understanding of inorganic biochemical processes that have active interfaces with the Earth’s geology, and in doing so, hold major implications for biosphere functioning, and the assessment, forecasting, and safeguarding of environmental health.

Microorganisms play a major role in shaping the distribution of chemical elements on earth. From the deep sub-surface to the atmosphere, they are participating in shaping the physical, chemical and biological properties of ecosystems. Over the last decade, the explosion of environmental genomic surveys revealed an extremely large microbial diversity in terms of taxonomy but also in terms of metabolic plasticity. A major challenge today resides in measuring and interpreting in situ the role of microorganisms for the regulation of global biogeochemical cycles (i.e., carbon, sulfur, nitrogen, iron, phosphorus, trace metals, etc.). Advances in geochemical imaging and fine-scale analyses as well as “multi-omics” approaches offer novel perspectives to study microbial activity in the environment. This session aims to bring together researchers working on a wide variety of studies and techniques that (i) quantify and reconstruct modern-day microbial elemental cycling and biological pathways in earth’s system, (ii) target key parameters of microbial activity (sources, fates, and fluxes of substrates, metabolic products and microbial markers) and of the biochemistry of enzymes, and (iii) develop novel methods and biomarkers to trace microbial activity in situ. Contributions related to method development, laboratory or field-based studies that can be applied over a range of natural environments (water column, marine sediments, wetlands, and soils) with implications for exploring the coupled evolution of life and the earth surface system in the past and present, and to predict future changes are welcome.

The search for life elsewhere in the Universe is fundamentally guided by Earth’s record of life and inhabited environments. By refining our understanding of how biology interacts with, and/or influences, its environment in the modern day, we will be able to more reliably ascertain the various geochemical and morphological manifestations of life through time. In this session, we will bring together new research on geobiological processes from a broad range of modern and ancient environments, including – but not limited to – hydrothermal vents, hot springs, acid mine drainage sites, caves, and carbonate and siliciclastic settings. We invite contributions that incorporate a novel, multi-scale (e.g., field to lab-based) approach, including the application of a multitude of in-situ analytical techniques (microscopy, SEM, EPMA, Raman, SIMS, LA-ICP-MS, XANES-EXAF, micro-CT, FIB-TEM, etc.), and on multiple types of biosignatures (morphological, textural, elemental, mineralogical, organic, isotopic, etc.), to tease apart biotic and abiotic inputs to the studied system. This session aims to highlight impactful, cross-disciplinary research on a variety of modern and early Earth environments that serve as possible analogues for life beyond our dynamic planet.

Microbial communities play a central role in carbon cycling in all ecosystems, with global significance. These processes span the building and breaking of organic compounds, both natural and manmade. The advent of genome-resolved metagenomics in concert with other 'omics and geochemical approaches has enabled study of metabolic and ecological interdependencies and community-scale carbon cycling interactions with unprecedented detail. Here, we invite contributions dealing with how microorganisms interact with their environment and each other to mediate transformations of inorganic and organic carbon, either directly (metabolic interactions) or indirectly (ecological interactions). We encourage contributions from multiple ecosystem types, from soils to the deep subsurface, freshwater to marine aquatic, glacial to geothermal environments and anything in between. We particularly welcome studies that employ multiple 'omics approaches that uncover multi-kingdom microbial community function and activity, those that employ tracers to track the fate of carbon, and modelling approaches that identify and predict microbial interactions.

The search for life in the solar system is one of NASA’s primary goals accomplished through understanding signatures that remain in the terrestrial rock record, analysis of returned samples to Earth and in situ exploration. Expanding our understanding of the range of potential biosignatures is required to accomplish this goal. One biosignature class that has thus far been relatively underexplored and underrepresented in published research are pigments. Pigments are a diverse class of molecules found across all domains of known life, including in astrobiological model organisms, such as haloarchaea, and have been to date found in the fossil record up to 1.7 billion years. Analysis of pigments in terrestrial settings help us better understand the early evolution of microbial communities, depositional conditions, and organic preservation. Traditionally, pigments are thought to be the result of complex pathways and non-random chemistries and have been defined as an “smoking gun” biosignature. More recently, however, the concept of pigments as an unambiguous biosignature has been called into question, given that certain complex molecules can be generated abiotically. In this session, we aim to highlight cutting edge research on pigments as potential biosignatures, including efforts on in situ and remote detection, detection in Earth’s fossil record, their synthesis and analysis, and potential synthesis in prebiotic systems.

The rhizosphere of blue carbon ecosystems supports many of the biogeochemical processes that make these environments ecologically and economically valuable. The roots of seagrasses, salt marsh grasses, and mangrove trees supply organic matter and oxidants to metabolically diverse soil microbial communities. Tidal cycles further structure the rhizosphere by flushing pore spaces and compressing or expanding redox gradients. Microbes respond rapidly to changing resource availability and environmental conditions, driving sharp differences in biogeochemical rates over short time scales and distances. Despite the centrality of rhizosphere processes to the functioning blue carbon ecosystems our understanding is still emerging. In this session we invite mechanistic, observational, and modeling studies that describe rhizosphere processes and link plant, microbial, and biogeochemical dynamics. This includes studies of natural, disturbed, restored, and created blue carbon ecosystems as well as lab and mesocosm experiments. We encourage studies that combine novel ‘omics and biogeochemical approaches that explore how plant-microbe-organic matter interactions contribute to carbon and nitrogen cycling under current and future climate and sea level conditions. Understanding small scale mechanisms and how they result in large scale ecosystem biogeochemical cycles is critical for predicting responses to disturbances and developing actionable management information.

Silicates are abundant on Earth and Mars in the form of volcanic and sedimentary deposits. Early earth siliceous deposits (i.e., geyserites, cherts, banded iron formations, etc.) have recorded and preserved the earliest evidence of life on earth.  Also are reported observations of siliceous deposits on Mars, Europa, and Enceladus.  However, the origin and formation of these extraterrestrial deposits have yet to be fully characterized and understood.  Often, the source of siliceous deposits is hydrothermal activity in which rock-water interactions lead to leaching of silica from host rocks leaving behind silica-enriched precipitates but can also be impact-related and/or diagenetic in origin.  Additionally, volcanic deposits (e.g., basaltic glasses) are known habitats for terrestrial life including iron-oxidizing bacteria that inhabit cold volcanic terrains analogous to ancient Martian settings, but more research is needed to explore the preservation potential of such environments. The habitability and preservation potential of volcano-sedimentary sequences is important for understanding early and present life on earth, and aid in searching for signs of life on other planets. We welcome proposals to our session that explore a suite of experimental, field, and theoretical approaches to processes that lead to the formation of sedimentary and igneous silicate deposits on earth and other planetary bodies within our solar system with implications for habitability, potential biosignature preservation, and origins of life.

The marine biological carbon pump (BCP) is a key modulator of ocean-atmosphere biogeochemistry, playing a profound role in shaping the Earth-life-climate system. The BCP drives the sequestration of atmospheric CO₂ in the ocean via the flux of organic matter produced through photosynthesis and biogenic carbonate, which is exported through sedimentation to the ocean interior and seafloor sediments. Notably, the burial of organic carbon in marine sediments is a key source of atmospheric oxygen. On the other hand, the majority of sinking organic carbon is oxidized through respiration in the water column, which depletes dissolved O₂ and recycles inorganic carbon and nutrients. Ocean oxygen concentrations, nutrient inventories, atmospheric O₂ and CO₂ levels, and carbon contents of marine sediments are thus all shaped by the strength of the BCP. Constraining the strength of the BCP is, therefore, central to reconstructing biogeochemical dynamics in the Earth system. Insight emerging from studies in both the contemporary oceans as well as the geologic record, however, reveal that the strength of the BCP is complex and highly variable, making the ecological and climatic impacts associated with BCP dynamics, difficult to assess.

Here we seek contributions that describe and predict the response of the Earth-life-climate system to changes in BCP efficiency across multiple timescales. In particular we welcome submission of multidisciplinary studies, both in the modern oceans as well as paleo records, including applications of organic and inorganic geochemistry, microbiology, chemical and biological oceanography, experimental and analytical isotope geochemistry, and numerical modeling.

In recent years there have been several studies reporting on evidence for life on Earth in the early Archean and Hadean. The proposed evidence has been dated to the period from 4.3 Gy to 3.5 Gy ago, and has mainly been on the morphology of the mineral phase or the isotopic and elemental composition of the carbonaceous remains found in ancient rocks. The session invites presentations reporting on new data or data from novel methods concerning the biosphere of the earliest Earth, as well as reviews of data from previous studies. Talks on geological data that reveal the environment in which early life thrived or the very nature of the earliest life are also welcome.

Since the beginnings of the industrial period (18th century), the exploitation of the underground resources has been constantly expanding, in line with the technological progress and the ever-increasing demand of mankind to satisfy their needs and comfort. However, this mining has generated and always generates large amounts of waste and modifications of the landscape, leading to new “geosystems” in direct contact with the atmosphere, hydrosphere and the biosphere. Accordingly, some elements and substances can be transferred to the environment, thus potentially posing risk for human health and ecology.

To face up to these social, economic and environmental issues, the mining/environment interactions must be accurately understood, and their impacts must be quantified to find ways to minimize them.

With a transdisciplinary point of view (mineralogy, pedology, geochemistry, biogeochemistry), the aim of this session is to cover all the aspects of mining/environment interactions, from the alteration of tailings to site reclamation, through element transfers and impacts on waters, soils and biomass. Submissions focus on innovative analytical approaches, experiments or modeling linked to mining/environment interactions are also welcome.

NOTE: This live event includes sessions 11aO2 and 8cO1, in that order, with no break between them.

The biogeochemical cycling of Fe and Mn is governed by mineral (trans)formation, sorption, and electron transfer processes. These processes also affect the fate of major and trace elements and thus the role of these elements as essential nutrients or toxic contaminants in aquatic and terrestrial systems. A better understanding of Fe and Mn biogeochemistry in governing the fate and impact of other elements and the response of environmental systems to changing conditions requires innovative research on a range of scales, from reaction mechanisms to global biogeochemical cycles. In this regard, factors such as molecular-scale reaction pathways, the nanoscale nature of Fe and Mn minerals, the interplay of abiotic and biotic processes, variations in reaction kinetics reflecting spatial heterogeneities and concentration gradients in soils and sediments, as well as interactions between organic carbon compounds and Fe and Mn minerals are relevant. This session aims to bring together scientists at all career stages interested in Fe and Mn biogeochemical processes and the impact of these processes on other major and trace elements across scales. We encourage experimental and theoretical contributions, including advances in methodology and analytical techniques, as well as laboratory and field studies. Topics include (but are not limited to) the formation and transformation of Fe and Mn minerals in abiotic or biotic systems, sorption processes on Fe and Mn mineral surfaces, rates and extents of electron transfer processes involving Fe and Mn minerals, and impacts of Fe and Mn cycling on nutrient and contaminant fate at different spatiotemporal scales.

Human activities have dramatically changed the rates, amounts, and forms of elements cycling through atmospheric, terrestrial, and aquatic ecosystems. Changes occur as both altered inputs to the environment (e.g., application of fertilizer, increased atmospheric deposition, extraction of minerals, and production of novel chemicals) and altered environmental conditions due to anthropogenic climate change (e.g., increased temperature, atmospheric carbon dioxide, drought, flooding frequency; altered precipitation frequency and intensity, sea salinity; and rising sea levels), and land use and land cover changes.

While previous research has often addressed individual elements or current, static conditions, predictions of elemental behavior amidst future global challenges should consider both that biogeochemical cycles are inherently linked to one another (so that the quantity or form of one element can impact the fate, transport, bioavailability and/or transformation of other elements) and that future environmental conditions will differ from what we typically measure and model today.

This session welcomes contributions that address biogeochemical cycles of major nutrients (e.g., C, N, P, S), essential trace elements (e.g., Fe, Se, Zn), or potential toxicants (e.g., As, Cd, Cr, Hg, Pb) with a focus on elemental cycle interlinkages and/or effects of future climate scenarios using field, laboratory, and theoretical observations from molecular to global scales. Linkages to consequences for ecosystem resilience, agricultural production, food chains, toxicity, or human health are also encouraged.

Radiogenic and stable isotopic compositions of environmental, geological, and oceanic archives have found frequent applications in understanding major and trace element cycles, fractionation mechanisms, and biogeochemical processes. These investigations are based on both observational and numerical modelling approaches. Experimental studies and atomistic calculations/estimations make it possible to understand the role of relevant parameters (e.g., temperature, pressure, pH, redox conditions, kinetic effects) that govern isotopic fractionation in nature. Further, isotopic investigations related to low-temperature aquatic processes have been successful in quantifying continental weathering and coastal oceanic processes, both in contemporary and past timescales. Recent studies have also stressed on using isotopic approaches to understand ongoing processes in extreme environments (e.g., Hg photoreduction, S-cycling in hydrothermal vents), which have been helpful in understanding the origin and sustenance of life on the earth.

In this session, we invite novel contributions focusing on the application of stable and radiogenic isotopes on:

• Experimental and modeling approaches to establish fractionation mechanisms of isotopic systematics
• Continental erosion processes and related elemental fluxes to the ocean.
• Estuarine processes (SGD, ion-exchange processes) to constrain coastal sources/sinks of trace elements and understand isotopic behaviour.
• Biogeochemical processes in extreme environments.

We encourage the submission of abstracts from both early-career and established scientists.

NOTE: This live event includes sessions 11eO2 and 11dO1, in that order, with no break between them.

Earth’s Critical Zone, the thin layer supporting life on Earth, is complex, heterogeneous, and responds dynamically to changing meteorological and environmental conditions. Various biogeochemical processes affect the dynamics and cycling of many critical elements, from nutrients to metals, impacting Earth’s environment as well as their interactions. Representing and quantifying the various transfer pathways of trace elements in atmosphere-vegetation-soil-groundwater-river systems remains challenging because of the complex environmental geochemistry, involving several inorganic and organic compounds. For instance, element cycling can be driven by intricate microbial, photochemical, physicochemical, or organic interactions, in water, vegetation and soil. Within soils and sediments, processes are heterogeneous on the grain scale, necessitating measurements that can explore the chemistry, speciation, and structure of materials in their native state. Recent advancements in solid-state characterization has allowed us to acquire this crucial information on key biogeochemical processes at the micro- to nanoscale.

The session aims at gathering experimental studies, field monitoring, and/or numerical modelling that shed light into the budget of critical elements by deciphering the sorption, re-mobilization, or speciation changes that affect their cycling in the environment. Emphasis is placed on how high-resolution techniques can be leveraged to gain greater understanding of broader global cycles to scale-up and link our understanding between the molecular and the global.

Understanding the environmental behavior of halogens, metalloids and other less-studied elements is essential for several research domains, including human nutrition, radiation protection, pollution control or tracing/dating approaches. Quantifying the various transfer pathways of these elements in atmosphere-vegetation-soil-groundwater-river systems remains challenging because of the complex environmental geochemistry, involving several inorganic and organic compounds. For instance, element cycling can be driven by intricate microbial, photochemical, physicochemical, or organic interactions, in water, vegetation and soil. These interactions may lead to volatilization into the atmosphere, drainage or accumulation into the soil through reaction with organic matter or trapping via sorption, by various biological and mineral components. We welcome contributions focusing on the understanding of the key processes involved in the mobility, distribution and transfer of any of the following elements, including stable or radioactive isotopes, with natural or anthropogenic origin: (i) halogens, (ii) metalloids, (iii) radionuclides and (iv) less-studied TCEs.

The session aims at gathering contributions that shed light into the budget of these elements by deciphering the sorption, re-distribution, or speciation changes that affect their transfer in the environment. Contributions may review the cycling of these elements in and between atmospheric, terrestrial, and aquatic compartments, as well as provide understanding about a particular process involved in the fate of individual or a small group of cited elements, independent of additional components. Presentations are expected to be based on compilations of new data obtained through laboratory studies, field experiments/monitoring, and/or numerical modelling, with particular emphasis on the environmental relevance of such approaches.

NOTE: This live event includes sessions 11eO2 and 11dO1, in that order, with no break between them.

Water interactions at the terrestrial-aquatic interface (TAI) can influence the biogeochemical cycles and ecological communities. Therefore, it is crucial to understand the hydrological controls and biogeochemical processes at the interface to advance our understanding and sustainably manage water resources. We invite presentations that focus on (i) the exchange of carbon, nutrients, metals and colloids and their reactive transport at the TAI; (ii) spatial and temporal distribution of solutes in the TAI; (iii) factors affecting the exchanges in the TAI; (iv) water quality; (v) adsorption and co-precipitation effects on water quality, including kinetic rate controls; (vi) effects of solutes and pollutants in the TAI. Studies on submarine groundwater discharge, saltwater intrusion, and exchange of contaminants of emerging concern and microplastics at the interface are encouraged. We also welcome new methodologies, including new measurement and modelling tools, machine learning approaches, big data analysis, and combining approaches to characterize surface water/groundwater interactions and associated forcing mechanisms at the terrestrial-aquatic interface.

Biogeochemical reactions between redox-sensitive elements like iron, sulfur, nitrogen or manganese and natural organic matter (NOM) drive redox processes controlling speciation of contaminants, and transformation of minerals, greenhouse gases, and nutrients in terrestrial environments. Natural complexities, including heterogeneity and polyfunctionality of NOM, intricate coupling of elemental cycling, and redox fluctuations leading to altered mobility via colloidal phases influence these biogeochemical reactions. Thus, it is important to develop a molecular scale mechanistic understanding of these processes in natural environments including soil, sediments, wetlands etc.

This session invites contributions on 1) coupled element cycling 2) impact of redox processes on contaminant and nutrient cycling and greenhouse gas emission 3) behavior and dynamics of NOM in soil and sediments 4) mineral transformation and 5) electron transfer reactions and other related topics. We welcome lab or field based experimental studies as well as theoretical modelling studies, and novel methodological insights that highlight mechanistic understanding of these processes.

Earth’s Critical Zone, the thin layer supporting life on Earth, is complex, heterogeneous, and responds dynamically to changing meteorological cycles. How this system responds to of the current rapidly changing climate is critical to humanity’s efforts to mitigate and adapt to these impacts. Biogeochemical cycles affect the dynamics and cycling of many critical elements, from nutrients to metals, impacting Earth’s environment as well as their interactions.  Within soils and sediments, processes are heterogeneous on the grain scale, necessitating measurements that can explore the chemistry, speciation, and structure of materials in their native state. Recent advancements in solid-state characterization has allowed us to acquire this crucial information on key biogeochemical processes at the micro- to nanoscale.

This session aims to bring together researchers employing state-of-the-art high-resolution techniques that probe elemental speciation and spatial distribution, chemical bonding environment, structure, and composition of (nano)materials in geo- and environmental matrices. These techniques include, but not limited to, electron microscopy (TEM, SEM), atomic force microscopy, tomography (ATP, micro/nano-CT), vibrational spectroscopy (micro/nano-IR/Raman), secondary ion mass spectroscopy (nano-SIMS), synchrotron-based techniques (XRD, XAS, XRF, X-ray scattering) or a combination thereof. Emphasis is placed on how high-resolution techniques can be leveraged to gain greater understanding of broader global cycles to scale-up and link our understanding between the molecular and the global.  Contributions from studies improving our ability to elucidate biological and mineralogical processes across length scales, including molecular dynamics simulations, field-scale experiments and case studies relevant to critical element cycling, are welcome in this session.

Earth’s Critical Zone, the thin layer supporting all life on Earth, is complex, heterogeneous, and responds dynamically from daily to annual meteorological cycles. How this system responds to applied forces of rapid climate change, as currently occurring, is critical to humanity’s efforts to mitigate and adapt to these impacts. Biogeochemical cycles have effects on the dynamics and cycling of many critical elements, from nutrients to metals, impacting Earth’s environment as well as interacting with each other.  Within soils and sediments, processes are heterogeneous on the grain scale, necessitating measurements that can explore the chemistry, speciation, and structure of materials in their native state. Tools such as synchrotron radiation have been used extensively, and are important for the characterization of the distribution and speciation of elements at molecular and microscopic scales.  A larger understanding from microscopic to broader field and global scales, while often considered to be an integral challenge in biogeochemsitry, are often not fully realized. These complexities are critical to efforts to mitigate the impacts of climate change, and to engineer courses of action to offset it.

With this session, we aim to bring together researchers working in these fields, with particular emphasis on how X-ray based techniques can be leveraged to gain greater understanding of broader global cycles to scale-up and link our understanding between the molecular and the global.  Contributions from experimental and modelling studies improving our ability to elucidate biological and mineralogical processes across length scales, relevant to critical element cycling, are welcome in this session.

Earth’s Critical Zone, the thin layer supporting all life on Earth, is complex, heterogeneous, and responds dynamically from daily to annual meteorological cycles. How this system responds to applied forces of rapid climate change, as currently occurring, is critical to humanity’s efforts to mitigate and adapt to these impacts. Biogeochemical cycles have effects on the dynamics and cycling of many critical elements, from nutrients to metals, impacting Earth’s environment as well as interacting with each other.  Within soils and sediments, processes are heterogeneous on the grain scale, necessitating measurements that can explore the chemistry, speciation, and structure of materials in their native state. Tools such as synchrotron radiation have been used extensively, and are important for the characterization of the distribution and speciation of elements at molecular and microscopic scales.  A larger understanding from microscopic to broader field and global scales, while often considered to be an integral challenge in biogeochemsitry, are often not fully realized. These complexities are critical to efforts to mitigate the impacts of climate change, and to engineer courses of action to offset it.

With this session, we aim to bring together researchers working in these fields, with particular emphasis on how X-ray based techniques can be leveraged to gain greater understanding of broader global cycles to scale-up and link our understanding between the molecular and the global.  Contributions from experimental and modelling studies improving our ability to elucidate biological and mineralogical processes across length scales, relevant to critical element cycling, are welcome in this session.

The isotope signatures of constituents in a system allow the tracing of sources, further fractionation processes and the underlying mechanisms and often quantified. Experimental studies and atomistic calculations make it possible to establish the relevant parameters constants (e.g., temperature, pressure, pH, redox conditions, vital (kinetic) effetcs) that govern various biogeochemical processes such as precipitation/dissolution, adsorption/desorption, acid-base reactions, microbial degradation, flow, and transport (advection/diffusion). These results then serve as a base for numerical interpretation of complex natural systems and the prediction of its future development. The objective of this session is to bring together isotope (bio)geochemists with focus on experimental and and modelling approaches. We also encourage the submission of abstracts from both early career scientists as well as more established scientists.

Climate change is one of humans´ major future challenges. Higher temperatures, droughts, floodings, changes in sea salinity, and rising sea levels are only some of the effects we start to perceive today. Even if we reach our goals from the Paris agreement regarding reduction of greenhouse gas emissions, many of those effects are expected to increase in the following decades. While the impacts on ecosystems and society are more visual, effects of a changing climate on biogeochemical cycles of nutrients and pollutants initially might escape the eye. Which pollutants are more likely to be mobilized in specific environments and affect the surrounding biota or even reach the food chain? Will we encounter nutrient deficiency in the near future? Which systems show resilience, and which ones will be most affected? How will this affect agriculture in a future where food security becomes more uncertain? What direct and indirect effects will these changes have on human health? As we prepare for these changes, there is an urgency to answer such questions and create the scientific basis to enable societies and policymakers worldwide to make sustainable decisions for a more resilient future. This session welcomes contributions that address biogeochemical cycles of different elements on the background of different effects of climate change, using field, laboratory, and theoretical observations from molecular to global scales.

Electron transfer reactions are central to the transformation of energy in the environment and underpin most biogeochemical cycles on Earth, including cycles of major elements such as C, N, S, Fe, and Mn, and trace elements such as As, Cr, Cu, or U. The behavior of these elements is often linked to the occurrence of redox reactions. Rates and extents of environmental redox reactions are a function of the (bio)availability and reactivity of electron donors and acceptors, which varies in each ecosystem on both spatial and temporal scales. For example, micro-scale heterogeneities in soils and sediments create redox hotspots which facilitate biogeochemical cycles potentially in contrast to those occurring in the bulk soil. Moreover, changes in rainfall patterns, rising temperatures, and other consequences of changing seasons or climate change may disturb these redox processes over space and time. A detailed understanding of environmental redox processes, with a focus on spatially and temporally resolved redox dynamics, is therefore indispensable to predict biogeochemical element cycles.  

In this session, we welcome contributions from field observations, laboratory manipulation experiments, as well as advances in analytical methods and modeling efforts related to environmental redox processes. 

Human activities have dramatically changed the rates, amounts, and forms of elements cycling through air, land, and water systems. This change occurs both as a result of direct inputs of elements to the environment – such as by fertilizer application, increased atmospheric deposition, extraction of minerals, and production of novel chemicals – and alterations to environmental conditions of Earth’s terrestrial and freshwater systems – including through land use and land cover changes or water withdrawals for residential, agricultural, and industrial uses.

While decades of research has probed element cycles in isolation, they are inherently linked to one another. Changes to the quantity or form of one element impacts the fate, transport, and/or transformation of other elements and compounds. This can result in elevated fluxes and storage to locations where elements are more bioavailable, increased production of toxic forms, and/or enhanced uptake into people and wildlife. The consequences for human health, therefore, cannot be considered in isolation, but instead are a reflection of these linked cycles.

This session seeks submission from researchers involved in field, laboratory, and modeling studies that address coupled biogeochemical cycles, where one or more elements influences the forms, availability, and/or redox state of another with consequences for human health. Efforts describing novel isotopic tracer approaches; evidence for linked cycles involving major nutrients (e.g., C, N, P, S), metals (e.g., As, Cr, Fe, Hg), or organic compounds; or development of new methods to assess emerging contaminants (e.g., PFAS, PPCPs, microplastics) are welcome.

Biogeochemical cycling of iron/carbon/nitrogen controls many environmental processes in natural and engineered wetland ecosystems, such as the fate of organic and inorganic contaminants, carbon/nitrogen fixation and greenhouse gas emissions. The intricate coupling of elements within these ecosystems have been studied extensively from many different perspectives covering geochemistry, soils science, environmental science, and microbiology. This session will highlight the state of the art in qualitative and quantitative assessment of elemental cycles in natural and engineered wetlands to help improve our understanding of how these biogeochemical processes influence the fate and mobility of contaminants and greenhouse gas emissions. We welcome contributions that focus on: 1) coupling of iron and carbon/nitrogen cycles, 2) modeling of element transformation, 3) extracellular electron transfer between microbes and minerals, 4) the interspecies interactions, 5) kinetics and thermodynamics, 6) impacts of elemental cycling on contaminant transformation, 7) greenhouse gas emission, and 8) other related topics.

Groundwater-surface water exchanges across terrestrial-aquatic interfaces (TAI) significantly influence hydrology, ecology, and biogeochemistry. These interfaces span across the summit to sea, within river corridors and coastal systems, including meanders, floodplains, wetlands, marshes, lakes, lagoons, hyporheic zones, and estuaries. To advance process understanding of terrestrial-aquatic exchanges and predict the interactions between the hydrologic, ecologic, and biogeochemical processes at those interfaces for sustaining water resources and promoting healthy ecosystems, we invite presentations covering the following topics: (a) reactive transport of carbon, nutrients,  metals, and colloids occurring at the TAI; (b) TAI biogeochemical spatial and temporal heterogeneity in characterization and scaling (c) geomorphological features and processes affecting exchanges from/to TAI, and (d) multi-scale properties of terrestrial-aquatic exchanges. Finally, we welcome new methodologies, including new measurement and modeling tools, machine learning approaches, and the combination of approaches to characterize surface water/groundwater interactions and associated forcing mechanisms for terrestrial-aquatic interfaces. 

The groundwater-surface water interface is a zone facilitating exchanges of nutrients, trace metals and pollutants between the surface water and groundwater. This interface plays a significant role in regulating the transfer of solutes between the two ecosystems. The transfer is driven by hydrological and geochemical processes and impacts the groundwater and surface water chemistry. Knowledge of this interface is crucial to understanding geochemical cycling and estimating the solutes reaching the groundwater and the surface water. To advance the understanding of the processes associated with the groundwater-surface water interface and its effects, we invite presentations that focus on: (i) the spatial and temporal variation of solutes in the interface and its movement, (ii) processes controlling the exchange of solutes in the interface (iii) effect of the delivery of nutrients, trace metals and pollutants in the groundwater or the surface water ecosystems (iv) new methodologies to identify and quantify the submarine groundwater discharge (v) reactive transport of solutes in the interface. We welcome studies focusing on the lacustrine, estuarine, and submarine groundwater discharge and the transformative movement of contaminants of emerging concern and microplastics in the interface.

Iron (Fe) and manganese (Mn) minerals play important roles in the cycling and environmental fate of many trace elements and thereby impact their availability as essential nutrients or toxic contaminants. For example, Fe(III) (oxyhydr)oxide minerals formed at natural redox boundaries in terrestrial and aquatic systems effectively scavenge dissolved oxyanions such as P, As and Sb, whereas Fe(II)-bearing minerals can reductively transform and immobilize many organic and inorganic contaminants. Poorly-ordered Mn(IV) oxides such as birnessite can be effective sorbents for many trace elements (e.g., Pb, Tl, Cd), but also strong oxidants that affect the redox cycling of organic compounds and redox-sensitive trace elements (e.g., Cr, Co, Se, As, Tl). A better understanding of the critical roles of Fe and Mn minerals in controlling the fate of trace elements requires cutting edge research across disciplines and on a range of scales, from reaction pathways to global biogeochemical cycles. This session aims to bring together scientists at all career stages investigating the structure, transformation and redox and sorption reactivity of Fe and Mn minerals across scales from molecular to field. We encourage experimental and theoretical contributions, including advances in methodology and analytical techniques. Topics include (but are not limited to) the formation of Fe and Mn minerals in abiotic or biotic systems, Fe and Mn mineral transformations, redox and sorption processes involving Fe and Mn minerals, or trace element speciation impacted by Fe and Mn minerals.

There is a lack of knowledge regarding the environmental processes governing the transport, compartmental transfers and fate of less studied species within the natural biogeochemical cycles of elements in Earth surface environments. This is particularly critical for elements of concern, involved in anthropogenic releases of both stable and/or radioactive origin (e.g., Co, Cs, Ga, Ge, In, I, Nb, Ni, Rb, Sb, Se, Sn, Sr, Te, and Y). We welcome contributions focusing on the understanding of the key processes involved in the mobility, distribution and transfer of any of the listed elements (i.e., stable or radioactive, with anthropogenic or geogenic origin). Studies focusing on individual or a small group of elements, independent of additional components (e.g, nutrients, competitive ions, etc.) are highly encouraged. In any case, these studies should include an environmental relevance such as direct field study sites or fundamental/laboratory approaches with a clear parallelism to realistic, environmental settings.

Abiotic and biotic reactions involved in Fe redox chemistry directly influence the cycling of metals and nutrients in terrestrial and freshwater systems. The mechanisms of how these Fe minerals behave in the environment are fascinating; however, studying these tiny, often nanoscale particles is challenging, and several critical gaps remain in understanding and predicting their reactivity and behavior. Advanced analytical tools (e.g., ⁵⁷Fe Mössbauer spectroscopy, atom probe tomography, in-situ electron microscopy, x-ray magnetic circular dichroism), as well as innovative applications of isotopes allow for detailed investigations at the atomistic level that offer mechanistic insights into processes that affect Fe mineral transformations at larger scales. This session aims to bring together researchers developing and using these tools to explore and unravel the complex redox chemistry of Fe minerals in terrestrial and freshwater systems.

Abiotic and biotic reactions involved in Fe redox chemistry directly influence the cycling of metals and nutrients in terrestrial and freshwater systems. The mechanisms of how these Fe minerals behave in the environment are fascinating; however, studying these tiny, often nanoscale particles is challenging, and several critical gaps remain in understanding and predicting their reactivity and behavior. Advanced analytical tools (e.g., ⁵⁷Fe Mössbauer spectroscopy, atom probe tomography, in-situ electron microscopy, x-ray magnetic circular dichroism), as well as innovative applications of isotopes allow for detailed investigations at the atomistic level that offer mechanistic insights into processes that affect Fe mineral transformations at larger scales. This session aims to bring together researchers developing and using these tools to explore and unravel the complex redox chemistry of Fe minerals in terrestrial and freshwater systems.

Natural organic matter (NOM) is ubiquitous in soils and sediments, and intimately linked to the majority of biogeochemical reactions that fuel element cycling. Owing to the  heterogeneous and polyfunctional nature of NOM it acts as a critical mediator/inhibitor of complex biogeochemical reactions in terrestrial ecosystems. Determining the role that NOM plays in different biogeochemical reactions continues to be a challenge. This session welcomes studies on how NOM influences biogeochemical reactions (e.g., redox, mineral transformation, microbe-mineral interactions, element cycling), as well as the environmental impact on the NOM itself (e.g., decoding (de)stabilization mechanisms due to climate change). We encourage contributions which focus on  different NOM sources with various functional complexities across the full span of experimental approaches (field/lab/modeling) at different spatial and temporal resolutions. Methodological insights into novel techniques currently used to characterize NOM and reaction pathways are also highly welcome. Our goal is to showcase recent discoveries, stimulate discussions, and identify the most pressing knowledge gaps with regards to the behavior and dynamics of NOM in soils and sediments from an ecosystem functions perspective.

Reactions at mineral interfaces (e.g., dissolution-precipitation, sorption-desorption, etc.) greatly influence the (bio)geochemical cycling of nutrients (e.g., C, P, N, Si) and trace elements (e.g., Cu, Ni, Zn), as well as contaminant dynamics (e.g., As, Cr, Hg, Pb, Se, U), in soils, sediments and water resources. To allow accurate prediction of the fate and mobility of metals and nutrients, it is therefore of key importance to obtain kinetic and mechanistic insights in their interaction with minerals found in (near-)surface and subsurface environments. Recent advancements in solid-state characterization has allowed us to acquire this crucial information on key (bio)geochemical processes at the micro- to nanoscale. This session aims to showcase research employing state-of-the-art high-resolution techniques that probe elemental speciation and spatial distribution, chemical bonding environment, structure and composition of (nano)minerals in geo- and environmental matrices. These techniques include, but not limited to, electron microscopy (TEM, SEM), atomic force microscopy, atom probe tomography, vibrational spectroscopy (micro/nano-IR/Raman), secondary mass ion mass spectroscopy (nano-SIMS), synchrotron-based techniques (XRD, XAS, XRF, X-ray scattering, tomography) or a combination of these. We welcome contributions from both laboratory and field-based experiments, as well as computational and theoretical studies. These include, but are not limited to, sorption and/or redox studies, incubation experiments, column studies, in situ / real-time experiments, mineral formation and/or transformation, molecular dynamics simulation, field-scale experiments of soils or water, and case studies.

Predicting water concentrations that are representative of reality is fundamental for the predictions of environmental impacts from industrial activities. This relies on a good understanding of the mechanisms governing water rock interactions.

Geochemical software (e.g., PHREEQC, GWB) are an integral aspect of these water quality assessment and predictions. These codes heavily rely on a set of data compilations, databases summarising our collective understanding of thermodynamics, kinetics and attenuation processes. In terms of water quality predictions, mineral solubility via thermodynamic modelling is well understood, kinetic controls have a less grounded theoretical framework, but lots of data, efforts have been made to gather those rates in databases (Palandri and Kharaka 2004, Hermanska et al. 2021). However, for surface complexation processes, codes generally rely on both historical theoretical framework and data (Dzombak and Morel, 1990). More recent mechanistic representation of surface complexation processes (CD-MUSIC) exists but, despite the wealth of available data no computer enabled databases for surface complexation exist at present. Several efforts are currently underway (e.g. Zavarin et al. 2022) to address this gap.

The objective of this session is to present the available work demonstrating how those approaches can improve understanding and numerical predictions and the resulting soil and water quality. Contributions from laboratory experiment, real world examples and modelling efforts are welcome.

Primary production in the Southern Ocean (SO) is limited by light, cold temperatures, and deficiency of iron (Fe) and manganese (Mn), which are essential trace elements for phytoplankton growth. However, satellite imagery shows annual extensive phytoplankton blooms downstream of SubAntarctic islands such as Crozet, Kerguelen, and South Georgia in the austral summer, which have been associated to the natural fertilization of trace elements via the land mass effect, an enhancement to the normal High-Nutrient, Low-Chlorophyll (HNLC) conditions of the SO. The SubAntarctic islands Gough and Marion are characterised by comparatively smaller blooms suggestive of a different land mass effect. Still, Fe and Mn provenance and co-limitation remains ambiguous in waters near these localised sources. To address this, the land mass effects is being tested by reporting the concentrations and interplay between dissolved and particulate Fe and Mn in the bloom areas near Gough and Marion islands, and its impact on primary production. The study is carried out in autumn (Marion island) and spring (Gough island), both key transitional growth seasons. Our results will give much needed insight into the efficiency of natural Fe and Mn fertilisation around islands, as well as feeding as observations in modelling SO productivity. Additionally, the results are coupled with a 1D Box model by use of Pelagic Interaction Scheme for Carbon and Ecosystem Studies -volume 2 (PISCES-V2) model to simulate and monitor the concentrations of Fe and Mn above and below the mixed layer downstream and upstream of the islands.

Primary production in the Southern Ocean (SO) is limited by light, cold temperatures, and deficiency of iron (Fe) and manganese (Mn), which are essential trace elements for phytoplankton growth. However, satellite imagery shows annual extensive phytoplankton blooms downstream of SubAntarctic islands such as Crozet, Kerguelen, and South Georgia in the austral summer, which have been associated to the natural fertilization of trace elements via the land mass effect, an enhancement to the normal High-Nutrient, Low-Chlorophyll (HNLC) conditions of the SO. The SubAntarctic islands Gough and Marion are characterised by comparatively smaller blooms suggestive of a different land mass effect. Still, Fe and Mn provenance and co-limitation remains ambiguous in waters near these localised sources. To address this, the land mass effects is being tested by reporting the concentrations and interplay between dissolved and particulate Fe and Mn in the bloom areas near Gough and Marion islands, and its impact on primary production. The study is carried out in autumn (Marion island) and spring (Gough island), both key transitional growth seasons. Our results will give much needed insight into the efficiency of natural Fe and Mn fertilisation around islands, as well as feeding as observations in modelling SO productivity. Additionally, the results are coupled with a 1D Box model by use of Pelagic Interaction Scheme for Carbon and Ecosystem Studies -volume 2 (PISCES-V2) model to simulate and monitor the concentrations of Fe and Mn above and below the mixed layer downstream and upstream of the islands.

Aqueous-solid interfaces host important biogeochemical redox processes that drive speciation changes and transformation of contaminants (As, Cr, V, Sb, Se, Hg, U etc.) and nutrients (P, Cu, Zn, Mo etc.), impacting their mobility and bioavailability in the environment. In particular, oxidation state change, dissolution/precipitation and complexation reactions, reactive intermediates, and interrelations of organics, minerals, and trace nutrients and contaminants, involving mineral phases containing the redox-sensitive elements S, Fe, and Mn are highly relevant in soils and sediments. Mineral transformation promoted by redox fluctuations can also play an important role in natural attenuation or facilitate mobility via colloidal phases. In this context, a comprehensive understanding of the molecular scale mechanisms driving the partitioning of mobilized contaminants and nutrients to the aqueous, colloidal, particulate or gaseous phase is necessary to better predict and respond to changes in groundwater, surface water, and soil quality in the context of rapidly changing climate and sea level rise.  

In this session, we welcome field as well as experimental and computing simulation studies focusing on mechanistic understanding of these redox reactions and how they control the fate and mobility of contaminants and nutrients in the environment. 

Aqueous-solid interfaces host important biogeochemical redox processes that drive speciation changes and transformation of contaminants (As, Cr, V, Sb, Se, Hg, U etc.) and nutrients (P, Cu, Zn, Mo etc.), impacting their mobility and bioavailability in the environment. In particular, oxidation state change, dissolution/precipitation and complexation reactions, reactive intermediates, and interrelations of organics, minerals, and trace nutrients and contaminants, involving mineral phases containing the redox-sensitive elements S, Fe, and Mn are highly relevant in soils and sediments. Mineral transformation promoted by redox fluctuations can also play an important role in natural attenuation or facilitate mobility via colloidal phases. In this context, a comprehensive understanding of the molecular scale mechanisms driving the partitioning of mobilized contaminants and nutrients to the aqueous, colloidal, particulate or gaseous phase is necessary to better predict and respond to changes in groundwater, surface water, and soil quality in the context of rapidly changing climate and sea level rise.  

In this session, we welcome field as well as experimental and computing simulation studies focusing on mechanistic understanding of these redox reactions and how they control the fate and mobility of contaminants and nutrients in the environment. 

Extremes are considered crucial environments that helps to better understand important scientific questions like the origin of life or how it can survive in low pH, low temperatures, or very high pressures. From the bottom of the ocean to the solar systems icy planets these extremes are now the new frontiers of science.

Stable isotope geochemistry has been used in the last decades to identify contamination sources (e.g Pb stable isotopes ratios) or to access isotope exchange reactions or kinetic processes (isotope fractionation). The application of stable isotopes techniques in extreme environments is relatively recent and is now becoming a powerful tool to understand the key scientific questions mentioned above.

The use Hg stable isotopes as a proxy of the photoreduction processes in polar regions or the use of the δ³⁴S to understand the biological process in hydrothermal vents are examples of the recent advances in isotope geochemistry in extreme environments.

This session aims to present and discuss the most recent advances on the application of stable isotopes biogeochemistry in extreme environments and the results obtained in such research.

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Transfer of trace elements from continental rocks to the open ocean via the estuarine regions serves as an interface between the geosphere and hydrosphere. These elements often act as micronutrients for marine organisms, and also, as indicators of atmospheric deposition, export fluxes, water circulation, and toxicity levels. Distributions of these elements and their isotopic compositions are regulated by multiple aquatic processes, including continental weathering, soil organic matter cycling, formation of secondary minerals (calcites, Fe-Mn oxyhydroxides) and colloids, surface-ground water interactions, ion-exchange processes, submarine groundwater discharge, and anthropogenic supply. The intensity of these processes varies both at spatial and seasonal scales; quantification of these variations in dynamic climatic scenarios has been achieved using trace elemental and isotopic compositions. These estimations are crucial in assessing the reliability of trace elements and their isotopes (TEIs) as proxies for past and contemporary hydrological processes. In this session, we welcome novel contributions related to freshwater aquatic processes and their linkages to coastal systems using observations and modeling of trace elements and their isotopic data. The session will specifically focus on (i) chemical erosion, elemental fluxes, and global carbon cycle, (ii) particulate-water interaction in watersheds, (iii) estuarine behavior and sources/sinks of trace elements, and (iv) reactive transport modeling of elements. Additionally, we also encourage submissions on the application of TEIs in understanding past continental processes, and anthropogenic impact on freshwater chemistry.

Understanding the environmental behavior of halogen elements and their different isotopes is essential for several research domains, including human nutrition, radiation protection, pollution control or tracing and dating approaches. Quantifying the various transfer pathways of halogens in atmosphere-vegetation-soil-groundwater systems remains challenging because of the complex environmental geochemistry, involving several inorganic and organic compounds. In fact, halogens cycling is driven by intricate microbial, photochemical, physicochemical, or organic interactions, in water, vegetation and soil, leading to their emission through volatilization into the atmosphere, drainage or accumulation through soil organic matter halogenation or trapping via sorption by various biological and mineral components. This session aims at gathering contributions that review the cycling of halogens in and between atmospheric, terrestrial, and aquatic compartments based on a compilation of most recent data obtained through laboratory studies, field experiments and monitoring as well as numerical modelling with a particular emphasis on biogeochemical processes that affect halogens distribution, budget, and changes in the speciation.

Mercury (Hg) is a ubiquitous toxicant harmful to human health and the environment. This global contamination issue is addressed under the 2017 Minamata Convention, which commits its current 138 parties to curb anthropogenic Hg emissions and releases. One common misconception is that mitigation policies will directly translate into reduced ecosystems contamination and human exposure. The effectiveness evaluation of the Convention and prediction of future Hg risks are complicated by the impacts of climate change and the rapid expansion of Artisanal Small-scale Gold Mining (ASGM) activities in developing countries, whose emissions/releases are still poorly constrained. In this session, we welcome studies that investigate the Hg biogeochemical cycle in the context of global change, i.e., the intertwined evolution of climate change and anthropogenic activities, including but not limited to Hg emissions or land use change. As we need a good baseline to detect the effects of global change, we also encourage submission of studies focusing on present-day Hg distribution, process understanding of Hg cycling, and pathways of Hg exposure. This session is meant to be highly interdisciplinary, with presentations on the key processes/compartments of the Hg cycle (atmosphere, ocean, terrestrial reservoirs, permafrost, biota, (de)methylation processes, bioaccumulation/magnification, etc.) and using a variety of methods (field measurements, laboratory studies, process-based and statistical modeling, genomics, Hg stable isotopes, benefit-risk assessment etc.).

NOTE: This live event includes sessions 12aO3 and 10bO1, in that order, with no break between them.

Just over two decades ago, the emergence of “non-traditional” stable isotope geochemistry techniques unlocked the viability of applying stable metal isotope geochemistry to research questions relating to human health and disease – a field now referred to as Isotope Metallomics. Since that time, stable metal isotope systematics have shown intense promise with respect to unveiling underlying mechanisms of metallostasis in both healthy and diseased states in the human body; with respect to the latter, numerous metal isotope systems have shown utility as indicators (biomarkers) of diseases such as osteoporosis, cancer, chronic kidney disease, and neurodegenerative diseases (e.g. Wilson’s disease, amyotrophic lateral sclerosis and Alzheimer’s). Moreover, recent technological advances in instrumentation and hyphenated componentry have allowed for increases in throughput capacity of modern instrumentation, and further standardization and scalability of stable metal isotope analytics. Such advances bring the field into a viable realm for the large sample cohorts and statistically robust datasets necessary for building medical biomarkers and diagnostic tools, and necessary for the future incorporation of such diagnostics into routine pathology tests (e.g. blood work).

This session aims to bring the community together in the place where much of this work started, to examine the previous and current state of the art, and to build a unified understanding of the bright and promising future of Isotope Metallomics.

With more than half of humanity already living in cities and 70% of the world population projected to live in urban areas by 2050, there is a greater need to better understand the anthropogenic and background biogeochemical processes in urban environments and how these processes contribute to environmental quality and human health in urban areas. While analytical procedures and substances of interest might be the same as in traditional geochemical studies, levels of pollutants and their sources, transport, transformations, and fate of chemicals are substantially different in urban areas. Moreover, urban biogeochemical processes are connected to environmental forcing and climate feedbacks through the cycles of water, carbon, and nutrients. Opportunities also exist through citizen science to engage communities and provide a valuable source of local information which can broaden our understanding and inform interventions. This session will bring together experts on the biogeochemistry, environmental geochemistry, ecohydrology, socio-ecology, and community science of the urban environment. Examples of topics include the transfer of urban contaminants to the hydrosphere; monitoring of pollutions in urban soil, air, water, biosphere, and technosphere; effects of urbanization on local and regional climate and water quality; applications of chemical, isotopic and microbial methods to greenhouse gas emissions from urban watersheds; biogeochemical effects of soil compaction and surface sealing; urban microclimates; and the biogeochemical benefits of sustainable urban development. Field, laboratory, and modeling studies are all welcome. We especially welcome submissions including citizen science data and/or unconventional approaches.

Plastic, PFAS (per- and polyfluoroalkyl substances), and other emerging contaminants such as pharmaceuticals are an integral part of our life and are now ubiquitous across the globe. Plastic is one of the most demanded and produced materials of our time with used plastics forming millions of tons of poorly managed waste. PFAS are widely used in many industrial and consumer products, and their chemical stability has led to wide distribution in the environment. Currently, plastic and PFAS have been found in all environmental compartments. Exposure to light, moisture, heat, biological activity, and other factors causes plastics to fragment into pieces, ranging in size from a few centimeters to the nanoscale, that are bioavailable to living organisms and plants. Chemicals associated with plastics, including plastics additives and sorbed pollutants, are also of concern. For PFAS, thousands of compounds of varying chain lengths and structures have been identified. Abiotic and biotic reactions can transform PFAS into more mobile and toxic compounds during water and atmospheric transport. PFAS have been linked to a myriad of human and ecological health issues, ranging from cancer in humans to the size of amphibians. The diversity of sizes and chemical compositions makes it difficult to characterize the behavior and adverse effects of these ubiquitous contaminants. In this session, we welcome studies that will help understand the occurrence, sources, fate, behavior and impact of plastic, PFAS, and other emerging contaminants in the environment, including analytical developments, numerical modeling, field observations and experimental studies relevant to different environmental compartments.

Micrometric, sub-micrometric and nanometric particles, released in the environment after natural and anthropogenic processes, are the object of an interdisciplinary interest. Different fluid media that move through air, water, soils and rocks can release and transport such particulate, allowing its variable interaction with the biosphere. The main results of such interaction range from beneficial properties, as e.g. the transport of nutrient species, to largely hazardous effects of e.g. contaminant transport.

This session is aimed to explore the characterization, diffusion, environmental dispersion, human exposure pathways and toxicology of a variety of particulates, including elongate mineral particles (EMP), naturally occurring particulates, industrially relevant particulates, novel organic/inorganic nano-scale materials (ENPs) such as nanoplastics, nanopesticides and metal-based nanoparticles.

The assessment of the main effects of such particles grounds in the accurate characterization of their physicochemical properties, such as chemical and phase composition, morphology and surface charge driving association-, agglomeration- and aggregation- processes, but also determines the main processes under which they enter the biogeosphere and persist in these environments.

This session welcomes contributions aimed at providing further insights in the characterization of emerging particulate matter in relation to occupational and environmental health, in relation to water, air, and soil pollution, in the assessment and definition of mode of prediction of the particle persistence and long-term effects in the biogeosphere. The results of such studies could be useful to address novel policies of health and environmental risks assessment and of safeguard of the environment and citizen health protection.

Metals are both resources and contaminants, can be essential to life or markers of disease.  Inputs of trace metals to the environment continue to increase from sources such as the use of traditional energy sources (coal, oil, natural gas, nuclear power) and from extraction and use of mined materials, including critical minerals such as lithium, copper, cobalt and rare earth elements, which have been deemed ‘critical’ by many countries because of their economic importance and supply chain vulnerability.  Yet our knowledge of the environmental behavior, bioavailability, toxicity, and utility in disease diagnostics of many of these elements is severely lacking.  As an example, the application of non-traditional stable metal isotope geochemistry techniques to human systems has relatively recently created the field of isotope metallomics to answer questions of life sciences and human-environmental interactions. 

This broad session therefore seeks research on the origin, fate, transport, bioavailability, and toxicity of metals, metalloids, and radionuclides, including those listed as critical resources. As the two are intimately related, this session also seeks research related to the fate of such metals once they are within a biological system, and how such metals may be used to understand both healthy and diseased states; in the case of humans and vertebrates in general, such research is known as isotope metallomics. Topics for the session may include, but are not limited to: isotopic and chemical indicators of pollutant source, analytical determination in various matrices (including plant and animal tissues), experimental studies of biogeochemical transformation and trafficking (e.g. sorption, redox reactions, organic complexation, microbe-metal interactions, equilibrium and kinetic biological processes), and natural studies of metals and their isotopes in plant and animal materials.

Analytical developments in geochemistry including metal isotopes analysis, high-throughput ICP-MS, and laser ablation technology have provided new tools to trace metal sources and cycling in environmental and forensic sciences, ecology, archeology and paleontology. In parallel, novel mapping approaches have capitalized on the growing body of geochemical data to investigate environmental and anthropogenic processes driving the large-scale spatiotemporal geochemical variations in natural and human-managed soils, waters, and ecosystems. Besides this direct application in environmental sciences, geochemical mapping is also a useful tool to trace the provenance of food, archeological artefacts and the mobility of modern and ancient/extinct humans and animals. This session invites presentations exploring the advances and challenges of developing/applying novel geochemical and/or mapping methods with applications in environmental sciences, food safety ecology, archaeology and paleontology. We welcome submissions at any scale, from laboratory studies to global geochemical mapping efforts, using geochemical data from environmental substrates (e.g., soil, water, air), human produced material (e.g., food) or modern and fossil biological material (e.g., teeth, bones, tusks). We also welcome submissions focusing on modeling and probabilistic approaches to provenance and risk assessments in their specific fields.

The release of contaminants with complex compositions into the environment can impact water and soil quality that in turn affects ecological and human health. A detailed understanding of geological processes, environmental fate and transport of contaminants is key to designing innovative and sustainable remediation approaches. Studies are needed on source mobility, toxicity, environmental transport and exposure pathways, risks to receptors, and environmental resilience. Many conventional treatment techniques are energy intensive, low efficiency, and involve high operation costs. Among emerging and innovative solutions for environmental contaminants, natural attenuation, low-cost highly reactive mineral species, agro/bio-waste, and nano-adsorbents may offer sustainable solutions.

The aim of this session is to develop an understanding of the fate and transport of contaminants under varying geochemical conditions and to highlight innovative remedial measures for contaminated waters and soils. Treatment (physical, chemical, biological) studies paired with contaminant characterization and (geo)chemical modelling are encouraged related to pollutant removal, intentional waste reuse, resource recovery, and circular-economy-based approaches.

We encourage submissions related but not limited to 1) contaminant characterization in soils, water, and wastewater (industrial, agricultural, and energy-derived) and potential toxicity, 2) geochemical alterations of water and sediments at contaminant-impacted sites, 3) development of novel analytical, modelling, and experimental tools, 4) remediation approaches such as mineralization,  applied novel (nano)materials, and natural attenuation, and 5) execution of lab and field-scale experiments investigating biological and geochemical responses to anthropogenic contaminants. Focused contaminants include heavy metals, radionuclides, PFAS, PPCPs, VOCs, pesticides, textile dyes and fibres, and micro and nanoplastics.

Several new emerging contaminants have been identified in the past decade including perfluoroalkyl and polyfluoroalkyl substances (PFAS), pesticides, pharmaceuticals and personal care products, endocrine disruptors, nanomaterials, nano- and micro-plastics, and rare earth elements, among others. Many of these organic compounds and metals have become increasingly important both in the human health and high-tech industries. Although some are naturally occurring (e.g., rare earth elements) and others were initially thought to be chemical inert, and hence, not environmentally reactive, or toxic, more recent investigations reveal that several of these early hypotheses were flawed. Consequently, we seek contributions that target and link novel analytical and biogeochemical approaches to elucidate understanding of fate and transport of emerging environmental contaminants in the near-surface environment and at the interface between geofluids and mineral, organic, plant, and microbial surfaces. Studies involving molecular level techniques such as spectroscopic and synchrotron-based techniques, as well as surface and solution complexation studies, biogeochemical modeling, are all requested. We also welcome submissions describing applications of Compound Specific Isotope Analysis (CSIA) to track the fate of these emerging environmental contaminants.

The transition from traditional fossil fuel extraction to green energy requires the development of alternative energy sources, energy storage, and energy transport. Prospective alternatives include blue, green, or gold hydrogen, as well as large quantities of critical raw materials including lithium, cobalt, nickel, and rare earth elements to be used in energy infrastructure such as magnets, motors, alloys, batteries, and solar panels. The traditional mining of these critical raw materials has been limited to specific geological domains that are abundant in only some countries or permitted by local environmental regulations, which creates shortages in supplies and geopolitical constraints for future large-scale production and utilization.  Mining and production of these materials will inevitably pose environmental impacts that could further limit the global supply chains for these critical resources and inhibit the transition to low-carbon energy sources. The water footprint of mining critical raw materials, especially in arid areas is another major constrain for sustainable extraction of materials required for the green revolution. This session will explore the geochemistry and the environmental implications of exploration for these critical resources and the utilization of green energy sources. We invite scholars to present novel research on the wide spectrum of the geochemistry of alternative energy sources and the potential environmental impacts induced from mining, processing, and recycling of critical raw materials.

Continuous industrial developments lead to a proliferation of new organic/inorganic nano-scale materials (ENPs) such as nanoplastics, nanopesticides, metal-based nanoparticles etc., released to the environment via the aquatic phase potentially polluting water resources. The soils are treated as sinks of ENPs either due to direct field application of ENPs in the form of pesticides or the utilization of contaminated waters for agriculture. The physico-chemical properties of these materials e.g. morphology, surface charge etc., determine their aggregation behavior, mineral/natural organic matter interactions and therefore the mobility and environmental impact on the biogeosphere (plant cells, microorganisms and aquatic species). The long-term persistency of ENPs in the environment is of utmost concern due to their accumulation in various environmental matrices relating to their trophic transfer possibility. In synergy with other co-contaminants, due to enhanced mobility, the ENPs might contribute to secondary water/soil pollution. Identification of ENPs in various environmental samples (water, wastewater, sludge, soils) at lower limits has been challenging. Apart, transfer mechanisms through cell walls, protective mechanisms, bioavailability as nutrients or toxic mechanisms are a matter of research.    

We encourage contributions from analytical method development, laboratory-scale and field-scale studies and numerical approaches to predict the long-term fate of these anthropogenic nanoparticles as nutrient carrier, contaminant or remediation approach. Especially contributions focusing on the bio-geo interface in subsurface environments are welcome.

Current trends toward greater use of high technology and renewable energy sources are driving exploration and mining for rare and critical commodities that sustain these technologies. Criticality is determined by economic importance and vulnerability to supply chain disruptions that could affect production of technologies reliant on the commodity.  Commodities or commodity groups listed as critical in the United States are aluminum, antimony, arsenic, barite, beryllium, bismuth, cesium, chromium, cobalt, fluorspar, gallium, germanium, graphite, hafnium, indium, iridium, lithium, magnesium, manganese, nickel, niobium, platinum-group elements, rare-earth elements, rhodium, rubidium, ruthenium, scandium, tantalum, tellurium, tin, titanium, tungsten, vanadium, yttrium, zinc, and zirconium.  Little is known about the bioavailability, toxicity, and environmental behavior of many critical minerals. Understanding the biogeochemical processes controlling fate, transport, and  bioaccumulation can inform the assessment of risks as bioaccumulation is often a precursor of toxicity.  Understanding these processes can contribute to developing sustainable mining techniques to exploit newly discovered sources of these materials, as well as sustainable remining techniques to recover these commodities from mine waste. As well, understanding their bioavailability and toxicity can assist in developing remediation strategies for mine waste containing these commodities.  This session seeks nascent through mature research detailing the bioavailability and toxicity of critical minerals, as well as studies describing environmental behavior and effects of critical minerals in both pristine and human-impacted areas, including, but not limited to, the mined environment.

Emerging pollutants (EPs) are often defined as synthetic or naturally occurring substances that are not commonly monitored or regulated but demonstrated or suspected to cause detrimental environmental effects. These contaminants include, e.g., pharmaceuticals, personal care products, various metals, and nanomaterials. These pollutants have a complex behavior controlled by the critical zone’s biogeochemistry. Some data are available on these substances’ fate mainly obtained from standardized tests. Nevertheless, our knowledge regarding EPs in complex and natural environments remains scarce. This session aims to address our understanding of the bio-physical-chemical mechanisms controlling the fate of these substances and associated risks, including mobility, spatial distribution, accumulation, transformation, and treatment /remediation solutions. We encourage submissions examining all aspects of the biogeochemical fate and speciation of EPs especially nanoparticles/colloids, metal ions and/or treatment strategies. We are interested in laboratory and pilot-scale experiments and field characterization/trials.

With more than half of humanity already living in cities and 70% of the world population projected to live in urban areas by 2030, there is a greater need to better understand the sources, transport, transformations, and fate of chemicals in urban environments and how biogeochemical processes contribute to environmental quality and human health in urban areas. Moreover, urban biogeochemical processes are connected to environmental forcing and climate feedbacks through the cycles of water, carbon, and nutrients. This calls into question how ongoing urbanization alters regional and global biogeochemical cycles and, hence, how urban biogeochemistry should be represented in earth system models. This session will bring together experts on the biogeochemistry, environmental geochemistry, ecohydrology, and socio-ecology of the urban environment. Examples of topics include the transfer of urban contaminants to the hydrosphere; effects of urbanization on local and regional climate and water quality; applications of chemical, isotopic and microbial methods to greenhouse gas emissions from urban watersheds; biogeochemical effects of soil compaction and surface sealing; nutrient budgets of cities; urban microclimates; the mineralogy, geomicrobiology and hydrochemistry of brown fields; and the biogeochemical benefits of sustainable urban development. Field, laboratory, and modeling studies are all welcome.

Approximately one-third of the terrestrial area falls under agricultural land use that has remained relatively stable over decades to feed the world population. While the influence of population growth on food security and sustainable growth is still being gauged, some known and unknown culprits have emerged in the process due to multifaceted technology and lax regulations to boost agricultural yield. The agriculture soils are under immense pressure due to the release of excessive nutrients, heavy metals, PFAS, microplastics, PPCPs, organic solvents, and fuels from organic/inorganic fertilizers, pesticides, biosolids, atmospheric deposition, operating machinery, etc.

The wide range of contaminants in agricultural soils with complex speciation under varying geochemical conditions may impact soil organisms and plants or seep into groundwater aquifers, altering their environmental fate. Therefore, a detailed understanding of contaminant chemistry in the agro-environment can serve as a vital tool in the strategic designing of innovative and sustainable remediation approaches. Among emerging solutions for soil and groundwater contaminants, zero-cost bio-degradable and agro/bio-waste in designing nano-adsorbents/ catalysts/ disinfectants may align with principles of green chemistry and circular economy.

In this session, we equally encourage submissions on (i) the fate and impact of plastic debris, PFAS, heavy metals, and other emerging pollutants in soil agro-environment and (ii) novel techniques, materials, and approaches for pollutants removal from soils and groundwater aquifers, including the understanding impact of environmental parameters, process designing, and optimization. The session covers multiple aspects ranging from lab-scale studies and soil-mesocosms to field-scale experimental observations.

In the past years, certain trace elements hitherto only used as geochemical proxies have gained increasing societal and economic importance due to their restricted and insecure supply and high importance for high-tech applications. These metals are now included in the lists of critical raw materials, published, e.g., by the EU and the USGS. Critical metals are, for example, the rare earth elements and the platinum group elements, but also more “exotic” ones like antimony, gallium, germanium, hafnium, indium, scandium, tantalum, tungsten and vanadium.

Although the increasing application of these metals results in a growing input from anthropogenic sources into the environment, knowledge of their environmental behaviour, their bioavailability and their (eco)toxicity are still in their infancy. This limited knowledge is partly caused by the fact that many of these metals occur at very low concentrations in the natural environment, posing additional analytical challenges.

This session collects contributions related to critical high-technology metals in soils, riverine, lake and seawater systems as well as in plants, fungi and animals that live in those habitats. Potential contributions include studies on a) their anthropogenic input, b) their analytical determination in various matrices, also including analysis of plant and animal tissues, c) their geochemical behaviour in Earth’s surface systems, i.e. the critical zone, d) studies on bioavailability and (eco)toxicity, and e) rehabilitation of contaminated sites. 

We especially welcome contributions from Early Career scientists and interdisciplinary projects that focus on research along the interface of bio-, geo- and soil sciences.

Compound-Specific Isotope Analysis (CSIA) is a powerful tool to track the fate of organic chemicals in contaminated environments. It is now used widely to identify and quantify the extent of transformation of legacy groundwater contaminants, e.g., benzene, toluene, and chlorinated solvents. More recently, new applications of CSIA to trace emerging organic contaminants (e.g., herbicide atrazine; corrosion inhibitor benzotriazole, antimicrobial triclosan) have shown its potential to track the fate of many more contaminants in both surface water and groundwater environments. These applications come with new analytical and data interpretation challenges, e.g., to deal with low concentrations, organic-rich water matrices and the multiplicity of co-occurrent transformation processes in surface water environments (e.g., phototransformation and biotransformation). In this session, we invite submissions on CSIA method development for sample preparation and analysis as well as experimental, field, and modeling studies aiming at determining isotopic fractionation patterns associated with transformation or transfer processes and/or applying them to interpret field data in industrial, agricultural, and urban environments.

Several new emerging contaminants have been identified in the past decade including perfluoroalkyl and polyfluoroalkyl substances (PFAS), pharmaceuticals and personal care products, endocrine disruptors, nanomaterials, rare earth elements, and tungsten, among others. Many of these organic compounds and metals have become increasingly important both in the human health and high-tech industries. Although some are naturally occurring (e.g., rare earth elements and tungsten) and others were initially thought to be chemical inert, and hence, not environmentally reactive, or toxic (i.e., PFAS), more recent investigations reveal that several of these early hypotheses were flawed.  Consequently, we seek contributions that target and link novel analytical and biogeochemical approaches to elucidate understanding of emerging environmental contaminants in the near-surface environment and at the interface between geofluids and mineral, organic, and microbial surfaces. Studies involving molecular level techniques such as high-energy X-ray spectroscopy, as well as surface and solution complexation studies, biogeochemical modeling, and when appropriate, isotopes systems are all requested.

Environmental contamination arising from anthropogenic activities threatens the quality of natural compartments such as soils, sediments, surface and groundwater. Among pollutants, contaminants of emerging concern (CEC) such as pharmaceuticals, antimicrobial resistance (AMR), nanoparticles, and nano- or microplastics present a growing interest in recent times. These elements are released into the environment in growing amounts, mainly as part of the waste of various industrial, farming, and domestic activities. Furthermore, in the context of climate change and the circular economy, it is mandatory to reuse wastewater and nutrient-rich waste products (biosolids, manure, or other organic wastes) in agriculture. This results in the simultaneous presence of several classes of CEC, metallic trace elements (MTE), or other organic pollutants in agriculture and environment, which may pose a risk to these systems. Therefore, a detailed knowledge of these biogeochemical processes is necessary to assess their impact on living organisms and human health.

For this session, we invite contributions studying the origin, behavior, fate, and impact of CEC in the environmental and agricultural systems. These include laboratory and field experiments, speciation, interaction and mobility, plant uptake, the (eco)toxicological impacts of the release of different forms of contaminants, and potential exposure pathways. Contributions dealing with (bio)geochemical modeling, molecular scale studies (spectroscopic and synchrotron-based techniques), cocktail effect, and the impact of soil amendment are also welcome.

Many countries continue to examine their reliance on traditional energy sources, including coal, oil, natural gas, and nuclear power, in the face of climate change and shifting political economies. Emissions of toxic trace elements from processes associated with these industries, like gas and oil production, historical releases of radionuclides from nuclear reactors, and disposal of coal combustion residuals, pose significant environmental and health risks, which have the potential to be exacerbated with aging infrastructure and intensification of hydrologic extremes. We welcome multidisciplinary and innovative approaches to examine the origin, mobility, and bioaccumulation of contaminant metals, (organo)metalloids produced by front- and back-end processes in the coal, oil, natural gas, and nuclear industries. Submissions are encouraged from any scale of study and may span the periodic table from Li to the actinides. These topics include, but are not limited to, isotopic and chemical indicators of pollutant source, experimental studies of biogeochemical transformation (e.g. sorption, redox reactions, organic complexation, microbe-metal interactions), multi-scale models and data-driven approaches to determine metal(loid) fate in air, water, and soil, and biomonitoring of human and ecosystem impacts.

Metals in river sediments from a semi-arid Mediterranean basin (Tafna River, Algeria) were investigated from upstream to downstream during contrasting hydrological conditions in 2014 and 2015.

The level and origin of the traces elements contamination were evaluated from a semi-arid Mediterranean basin, using geochemical indicators.

Elements were grouped by their level of contamination: high (Pb N Cd N Zn N Cu) and low (Al, Fe, Cr, Co, Ni). Multiple local sources of contamination were identified (industrial, agricultural and domestic waste). During storm events, the upstream dams can either be secondary sources of contamination or dilutors through particles derived from natural erosion. The contamination was slowed down stream due to the river geomorphology, but eventually washed into the Mediterranean Sea by intense storm events. Naturally derived elements (Co, Ni, Cr, As) were associatedwith Al, Fe and Mn oxides or clays, and anthropogenic originated metals with phosphorus (Cd and Zn), sulphur (Cu) and POC (Pb enrichment). Cadmium and Pb were the most available metals upstream and at the outlet, but their availability was not strictly related to their degree of contamination.

This session is aimed to explore the characterization, diffusion, environmental dispersion and toxicology of a variety of breathable inorganic particles and elongate mineral particles (EMP).
The subject material can be of natural, anthropogenic or synthetic origin. The natural particles may include quartz and feldspar fragments, asbestiform fibers and EMPs that occur diffusely in many world areas or other particles, e.g. that generated by disruptive phenomena as ashes from volcanic eruption. The session comprises contribution studying anthropogenic and synthetic particles as for example cristobalite, vitreous and titanium dioxide fibers, as well as hazardous particles that can be dispersed in urban environment as in natural and professional environments, depending on natural and/or anthropogenic activities.
Besides the characterization of these materials and the possible interaction with the biosphere, the determination of the risk assessment and of the possible health hazard can lead to a thorough discussion that can benefit the local environmental policies and the
communities through prompt decisions of social and political relevance by government bodies.
This opens the possibility also for editing of guidelines and international plan of intervention and coordination that leads to a better safeguard of the environment and citizen health protection.
This symposium is aimed at attracting an interdisciplinary audience from geosciences, material sciences, chemistry, biology, physics medical sciences, to unravel the complex topics that interaction between solid toxic species and the biosphere determines.

Metal isotope geochemistry is playing an increasing role in understanding the ecology, diet, mobility, and history of modern and ancient ecosystems and human societies. The fractionation of bio-essential metal isotopes (e.g., Ca, Mg, Sr, Zn) in marine and terrestrial ecosystems has brought complementary evidence to classic isotopic tracers (CNOS) to understand the diet and reproduction of extant and extinct species. In parallel, radiogenic metal isotopes (Sr, Nd, Pb) are increasingly used to reconstruct the mobility of humans and animals in modern and ancient ecosystems. These novel applications of metal isotope geochemistry are supported by the rapid and continuous improvement of methods to sample, treat, purify and analyze isotopes in modern and fossilized animal tissues. The growth of metal isotope research has also led to the development of controlled-laboratory studies and data science approaches to test and enhance the applicability of these tools for mobility and dietary reconstruction. This session invites presentations exploring the advances and challenges of applying novel isotopic techniques in ecology, paleoecology, archaeology and paleontology. We welcome submissions of: 1) case studies applying single or combined metal isotope analysis to investigate specific questions in these fields, 2) methodological studies that test or revisit current analytical or interpretative framework, and 3) modeling perspectives (e.g., data compilation, physiological modeling, isoscape, web-interfaces) that aim to push forward the applicability of metal isotope tools.

Mineralization reactions are of great importance in many geochemical processes. But, these reactions can also be used to help solve important societal problems. For example, mineral precipitation and/or replacement can be very effective in decontaminating water polluted with heavy metals or organic molecules, extracting rare earth elements, capture and store CO₂ or mitigate acid mine drainage issues, to name just a few. The most commonly involved mineral species in these methods are carbonates, silicates and sulphates, which are all widespread and abundant, have a relatively low cost per tonne, and which usually have a high reactivity. Consequently, mineral-driven reactions are an economically viable route to help remediate a broad range of environmental issues.

In this session, we invite contributions that involve experimental and/or theoretical studies addressing the fundamental aspects of mineral reactions (including, nucleation, growth, transformation and replacement of minerals), both in natural and engineered environments. But, we also strongly anticipate to receive abstracts that propose (I) new experimental techniques (in situ or ex situ), including real-time laboratory and synchrotron measurements, to probe the reactivity of minerals or (II) novel applications of mineral-based reactions related to environmental remediation and circular economy.

The intensive use of chemicals in the past decades combined with inadequate waste management resulted in many contaminated sites worldwide. Moreover, as the understanding of the fate and toxicity of anthropogenic chemicals improves, new contaminants are being identified as pollutants of concern. Human exposure to water and soil contamination may cause adverse effects such as cancer, neurotoxicity, and endocrine disruption. Conventional water and soil decontamination approaches, especially those used at contaminated sites, are often expensive, energy-intensive, and inefficient in the long-term perspective. More cost-efficient and sustainable approaches to the restoration of contaminated water and soil are therefore needed. The aim of this session is to address innovative remedial options for contaminated waters and soils, including physical, chemical, and biological treatment strategies, along with identification and monitoring of pollutants in the environment. We encourage submissions examining both lab-scale, field-scale, and modeling studies emphasizing use of novel (nano)materials. Specifically, we invite combined works merging experiments and modeling. We focus on studies dealing with both legacy and emerging contaminants of various inorganic (e.g., toxic metals and metalloids) and organic (e.g., chlorinated ethenes, PCBs, PFAS) nature.

Solid and liquid wastes from oil and gas (OG) development pose potential risks to water resource quality and organism health, including humans. Releases of wastes require science to inform mitigation strategies and understand mechanisms controlling sources, movement, and toxicological effects of OG contaminants. Studies are needed on source mobility and toxicity, environmental exposure pathways and risk to receptors, and resilience of the environment. Evaluating re-use potential requires better understanding of the synergistic effects of produced water source compositions. The potential environmental implications of re-using OG wastewater mixtures and/or treated effluents may differ from other wastewater streams. Although re-use of OG wastewaters for hydraulic fracturing may conserve fresh water for other uses, and commodity recovery from OG wastes may provide needed materials through existing waste streams, assessments of industry reuse standards are warranted to guide treatment and evaluate impacts. Landfilling and land-application of drill cuttings and spent drilling fluid are management strategies used to dispose of these wastes. This session welcomes interdisciplinary studies that include 1) characterization of the composition of OG solid and liquid wastes, 2) measurements of the geochemical alterations of water and sediments at waste-impacted sites, 3) identification of potentially harmful compounds to aquatic and human health and elucidating their modes of action, 4) examination of the potential environmental and human health impacts of novel OG water reuse and commodity recovery technologies, 5) development of novel analytical and experimental tools, and 6) execution of lab and field-scale experiments investigating biological and geochemical responses to OG wastes.

Per- and polyfluoroalkyl substances (PFAS) and other novel emerging contaminants are now ubiquitous across the Earth’s surface. These compounds are often difficult to break down and have been linked to a myriad of human and ecological health issues ranging from cancer in humans to the size of amphibians. Dubbed ‘forever chemicals’ due to their recalcitrance, PFAS may transform from less mobile to more mobile and toxic forms during vadose zone and groundwater transport. The rapid production and release of new compounds has so far outpaced the global capacity for testing and monitoring—perhaps moving our planet past a novel entity planetary boundary as recently reported. This session welcomes abstracts on the transport, transformation, and natural or enhanced break down of emerging contaminants including PFAS, as well as research on the ecological and human health effects. Laboratory and field- based research linking transformation of PFAS and other emerging contaminants to geochemical and microbial processes are sought. Research exploring PFAS mass flux and storage in global compartments, source fingerprinting, and the use of emerging contaminants as hydrological tracers are also encouraged.

Plastic is an integral part of almost all the necessary goods of our life and one of the most demanded and produced materials of our time. At the end of their lifetime, used plastics form millions of tons of waste that are poorly managed. As a result, plastic accumulates in the environment and is disseminated across environmental compartments by atmospheric transport, and surface, subsurface and river runoff. Currently, plastic has been found everywhere on our planet in all environmental compartments including aquatic, atmospheric, and terrestrial systems. Exposure to light, moisture, heat, biological activity, mechanical stress, and other factors causes plastics to fragment into smaller pieces, ranging in size from a few centimetres to the nanoscale. Small plastic particles such as microplastics (MPs) and nanoplastics (NPs) are bioavailable for a wide number of living organisms from zooplankton to mammals and to plants, with potential negative consequence for the biosphere. Besides the negative impact related to the particles themselves, there is concern about plastics associated chemicals including additives and pollutants adsorbed from the environment. The diversity of size, shape, and chemical composition makes it difficult to determine the behaviour of this ubiquitous pollutant and its adverse effects on ecosystems and human health. In this session, we welcome studies that will help understand the occurrence, sources, fate, behavior and impact of MPs and NPs in the environment, including analytical developments, numerical modeling, field observations and experimental studies relevant to the atmosphere, land, ocean and biosphere.

Natural radioactivity affects our environment due to cosmic radiation, their interaction with atmosphere, and terrestrial source from soil and minerals in rocks linked to alpha decay processes of the principal primordial radionuclides. Among the terrestrial sources, radon gas is considered the major source of ionizing radiations exposure to the population and an indoor air pollutant due to its harmful effects on human health as it is considered the second carcinogen behind tobacco.

The Geogenic Radon exerts the main control on Indoor Radon Concentrations, so the identification of areas characterized by radon enhanced is critical in hazard assessment. Radon migration and transport in-soil and surface emission are controlled by geogenic and tectonic sources; radon migration along permeable pathways may enhance the Radon content at surface modifying the shallow distribution of the geogenic activities. Conversely, indoor radon concentrations are also defined by anthropogenic and meteorological factors (e.g. permeability, buildings and architectural features, ventilation, occupation patterns).

This session aims to improve the knowledge of radon concentration and migration mechanisms in different geological compartments (e.g., minerals, rocks, soil, water) with further implications in the Indoor Radon Concentrations to assess health hazard from radon exposure, including: (i) study of Geogenic Radon sources, components and mapping; (ii) identification of Radon Priority Areas; (iii) radon health hazard assessment; (iv) groundwater contamination; (v) volcanic and active system monitoring and surveillance; (vii) atmospheric tracing including greenhouse gases and pollutants.

Contributions on novel methods and instrumentation for environmental radioactivity monitoring are also encouraged.

Ground/Surface water radionuclide’s contamination removal is one of the major challenging objectives of world due to increase in the nuclear power programme to meet the requirement of nuclear power as nuclear power generation is environmental friendly unlike thermal power generation. Thermal power generation is one of main source for green house gases. Thermal power causes emission of green house gases there by immense effect on climate change. Ground/Surface water radionuclide’s contamination caused by not only from anthropological sources of mining activity but also with natural leaching of radionuclide species, where the radioactive ore/mineral body intact with ground/surface water. World Health organisation (WHO) drinking water limits for uranium is 30 µg/l and 300 Bq/M³ for Radium. Different methods are available for uranium separation like Ion exchange, RO systems etc. IX & RO method required clean water with high capital cost. Some area in Andhra Pradesh, Telangana, Karnataka (Cuddapha basin, lambhapur & gogi) of southern India ground/surface water contaminated with Uranium by natural leaching where ground/surface water is intact with ore/mineral body. It necessitates the treatment of ground/surface water before using for drinking purpose/agricultural purpose. A new innovative chemical method developed for removal of Uranium and Radium. In this method uranium can be removed up to < 10 µg/l & near to 300Bq/M³ Radium from ground/surface water. Method working range, Effect of TDS, pH, & SO₄^2- are also studied on uranium removal from the ground/surface water by this method.

Following the recommendations proceeding from the publication of  the so-called "Blue book" by Arthur Darnley and other authors in 1996 (A Global Geochemical Database for Environmental and Resource Management. Recommendations for International Geochemical Mapping – Final Report of IGCP Project 259), in the last 25 years the use of spatial statistics and geographical information systems allowed to carry out the baseline geochemical mapping of continents and several individual countries. The global experience has been often the flywheel of local projects which mostly focused (and still do) on highlighting the connection existing between the environment and local populations in terms of life quality and health conditions.

This session aims at collecting contributions reporting the outcome of environmental geochemical studies based on different environmental media (soil, sediments, water, air), which make use of different spatial and not-spatial data elaboration methods with the purpose of contributing to the understanding of anthropogenic and natural processes underlying the geochemical patterns observed. Contribution dedicated to the use of geochemical data for the spatial assessment of risk in a deterministic or probabilistic perspective are also welcome.

The “One Health” concept is based on various interactions between humans and geochemical environments, particularly relevant to the health of ecosystems and communities, and is accentuated by external factors such as population growth, climate change, and the increasing exploitation of geochemical resources. The interface between health and geochemistry is a research field that combines multidisciplinary approaches and is often conducted using tools borrowed from geochemistry, geology, and environmental chemistry. An interdisciplinary approach makes it possible to unravel the link between the natural environment and human health, contributing to the improvement of a global society. The growing demand for healthy, high-quality food products led to strict regulations to obtain certification of authenticity and protect against fraud leading to increasing demand for appropriate scientific protocols. Territoriality studies are based on the hypothesis that the chemical elements found in plants and their products reflect those contained in the soil and, as a result, the geographical characteristics of the production area, such as soil type and climate, are considered relevant factors influencing the specific designation. Consequently, an accurate determination of the geographical origin would be necessary to guarantee the quality and territoriality of products. In recent decades, light and heavy isotope geochemistry, sometimes combined with multi-elemental analysis and chemometrics, has been applied to the authentication and traceability of the geographical origin of processed foods and beverages. This session welcomes contributions based on approaches including, but not limited to, medical geology, and geochemistry applied to food traceability, soil, and food chemistry.

Iron (Fe) has been critical to the advancement of human development for millennia. In more recent times, supported by decades of research, iron is again at the centre of a new wave of innovation and is emerging as a key element in solving major environmental challenges. The ubiquity of iron in almost any environment, coupled to its redox reactivity, has led to the development of many applications which use the element such as in water treatment, critical metal recovery, rare earth elements extractions, and phosphate recovery. Many of these applications take advantage of the ferrous (Fe(II)) or ferric (Fe(III)) oxidation states of iron or its presence in different minerals such as ferrihydrite, magnetite, goethite, pyrite or Fe-bearing clay minerals. These different minerals are naturally found in a range of sizes, including as nanoparticles, further enhancing reactivity with different metal and organic ligands. Whether through the synthesis of precisely controlled nanoparticles or in large reactive barriers, iron is finding a new wave of applications in this new iron age.

In this session, we invite abstract submissions from diverse researchers of any career stage that highlight the significance of iron in innovative and state-of-the-art applications. Possible research topics include but are not limited to: use of iron in treatment of drinking water in engineered vs. natural systems, iron nanoparticles in medical therapies, optimization of iron mineral synthesis pathways for targeted applications, for example, phosphate retention, rare earth elements extraction and critical metal recovery from mines.

Anthropogenic and background geochemical processes in urban areas, often termed urban geochemistry, are an area of growing interest. UN projections indicate that two thirds of the worlds population will live in cities by 2050. Urban areas remain some of the unhealthiest places to live, with people in towns and cities experiencing increased rates of non-communicable diseases, social isolation, and poor environmental quality. Often those communities with higher levels of deprivation are typically exposed to the worst environmental quality. While analytical procedures and substances of interest might be the same as in traditional geochemical studies, levels of pollutants, their distribution and combination, as well as their sources are substantially different in urban areas.

Community/citizen science has seen a similar growth in interest. It’s application in the geochemist’s world is often closely linked to urban geochemistry. Samples taken and data provided by interested citizens can broaden studies or even form studies on their own and provide valuable information which can guide interventions. At the same time there are challenges that need to be considered, for example data quality, sampling protocols and recruiment of engagement groups.

The aim of this session is to curate studies on geochemical processes and/or monitoring of pollutions in all compartments of urban areas (soil, air, water, biosphere, technosphere). These can be monitoring/field campaigns or modelling approaches, as well as lab experiments if suitable. We especially welcome, but are not limited to, submissions including citizen science data and/or unconventional approaches.

Recent advances in analytical, computational and observational techniques have driven major progress in the field of biomineralisation and in our understanding of abiogenic mineral formation, and have also provided invaluable mechanistic insights into geochemical proxy systems. The cross-disciplinary connection of these approaches has the potential to help disentangle the effects of biological mechanisms, abiogenic mineral formation processes and environmental conditions, when interpreting geochemical and morphometric proxy data.

To date, the link between environmental parameters and increasingly sophisticated proxy systems is largely based on empirical calibrations. Notwithstanding the enormous amount of important information that has been derived from this approach, our incomplete understanding of (bio)mineral formation pathways means that we have limited a priori knowledge of the connection between environmental conditions and the (bio)mineral properties that the proxy system depends on.

In this session, we hope to incite an interdisciplinary discussion that draws on both (bio)mineralisation- and proxy-focused approaches, to tackle the mechanistic origins of geochemical and other environmental signals in (bio)mineral archives. We welcome all contributions that target mechanisms of mineral formation and alteration in the context of proxy incorporation and preservation. This could include - but is not limited to - experimental, theoretical, analytical, or computational studies of the formation and geochemistry of mineral systems such as carbonates or apatites, which are commonly used in paleoclimate reconstructions.

Contributions of early career researchers and under-represented groups are especially encouraged.

The chemical and isotopic compositions of carbonate minerals provide a unique opportunity to reconstruct the environmental conditions that occurred during geological time. In this context, the incorporation of trace elements into carbonate minerals of biotic (corals, foraminifera, etc) or abiotic (speleothems, inorganic sediments) origin, has been routinely studied over the last five decades. Recently, our ability to precisely measure the isotopic composition of traces (e.g., Zn, Li, Ni, stable Sr) in carbonate minerals, led to the development of new environmental proxies allowing insights, e.g, on the past CO₂ atmospheric level, weathering, temperature, pH, and saturation state of the oceanic waters. This session aims to cover the full range of investigations on paleoenvironmental reconstructions and modern environment based on carbonate geochemistry. We invite contributions that explore carbonate-fluid interactions aiming to improve or develop new environmental proxies based on trace metals and their isotopes in carbonate minerals. Laboratory microcosms or abiotic experiments focusing on mineral dissolution/precipitation/growth experiments, adsorption onto carbonates, analysis of natural samples from biotic and abiotic, traditional and non-traditional stable isotopic fractionation and carbonate-fluid elemental and isotopic exchange mechanisms, investigations on modern or past environments, are encouraged. Contributions on climate variability and ocean dynamics on absolutely dated time scales from the distant past to the sub-annual records of the post-modern area, on the precision dating of coral archives and the reconstruction of coral ecosystem dynamics related to their growth as well as showcase studies of new, impactful applications of Δ47 and/or Δ48 measurements to various research fields, are also invited.

NOTE: This live event includes sessions 10aO1 and 13bO1, in that order, with no break between them.

Trace elements and their isotopes in the ocean play essential roles as regulators of ocean carbon production and marine biodiversity, as well as tracers of circulation and particle transport. This session highlights three areas of recent research that need critical attention. (1) Observational, experimental and modelling contributions on the distribution, flux and controls of particle-reactive elements from estuaries to open ocean. These particle-reactive elements such as rare earth elements, Th, Pa, Pb, Po, Be, involve processes and fluxes that are relevant in both the modern and paleo-ocean. (2) The impact of small-scale physical processes, including submesoscale (<10 km) and mesoscale (<100 km) circulation, turbulent mixing, and sea-ice transport and melting on bioactive trace metals (Fe, Mn, Co, Ni, Cu, etc.). Observational datasets on trace metals relevant to these processes are rapidly accumulating and state-of-the-art ocean modelling can use these as targets or predict distributions in areas with sparse data coverage. (3) The Southern Ocean as a whole, and the Indian Ocean sector in particular remains poorly observed for trace elements and isotopes. Presentations are welcome on the recent SWINGS (Southwest Indian GEOTRACES Section, Jan-Mar 2021) cruise as well as other Southern Ocean or GEOTRACES expeditions that investigate all aspects of marine trace element cycling including biogenic uptake, remineralization, particle fate, export, and circulation transport. Submission relating to all three of these areas are encouraged, and especially by early career scientists.

Seafloor hydrothermal systems and submarine volcanoes are crucial for the marine environment as they return buried substances, including metals and dissolved gases, from the Earth’s interior to the ocean and thus, over geologic times, control the composition of seawater and provide essential elements to the biosphere. Process understanding of the fate of hydrothermal products and discharges, including complexation and scavenging by hydrothermal particles can be used as tool for answering questions around the controls of hydrothermal systems, their evolution and activity over time and their potential impact on ocean productivity. This session will explore the fate of hydrothermal products and discharges proximal and distal to hydrothermal sources, the diagenetic and microbial processes they undergo after deposition, and their impact on the marine environment. We invite observational, experimental and modelling contributions, new approaches and new methodologies for shallow and deep hydrothermal systems from present and past times. We encourage submissions that will give new insights into the evolution of a hydrothermal system, organic-mineral interactions, spatial distribution and fluxes of products and discharges and the diagenetic alteration of hydrothermal products. Finally, there are many parallels between the impacts of marine vulcanism and ocean acidification which we encourage submitters to consider.

Recent advances in analytical, computational, and observational techniques have driven major progress in our understanding of how inorganic and organic material in the ocean is formed, preserved, or diagenetically transformed. This includes biomineralization, authigenic mineral formation, and the coupling between organic matter and minerals. This new understanding provides invaluable mechanistic insights into geochemical proxy systems, but also emphasizes the role of mineral formation and dissolution in global elemental and isotopic cycles. Dissolution of primary silicate minerals (primarily feldspars) consumes substantial amounts of CO₂ (silicate weathering), while biomineralization (e.g., opal from diatoms) and authigenic formation (e.g., glauconite, illite, celadonite, K-feldspar) of silicates has the opposite effect (reverse weathering); all are first-order processes with feedback to other components of the Earth system and are intimately linked with the carbon cycle. While the formation of (bio)minerals plays a major role in global elemental and isotopic cycles, such minerals also provide valuable archives of paleo-seawater and/or pore-fluid compositions. It is crucial that we better understand the mechanisms controlling the formation and preservation of marine (bio)minerals through time, which will improve our ability to interpret these archives. Furthermore, it is an open question how organic matter degradation/preservation, coupling of organic matter to inorganic phases, silicate dissolution, authigenic mineral formation and diatom production are coupled. This session aims to provide constraints for these knowledge gaps by gathering contributions from field and laboratory observations (taking advantage of metal isotope systems, e.g., Li, Mg, Si, K, Ca, Fe, Tl), regional and global modelling, and estimates for past/current/future scenarios.

Marine life and the oceanic environment have co-evolved for much of Earth’s existence. For instance, the rise of complex animal life on Earth has been linked to the oxygenation of the ocean-atmosphere system, which in turn was impacted by nutrient cycling, tectonic forcing, volcanic outgassing and weathering processes. Furthermore, the Phanerozoic, spanning the last ~540 Ma, witnessed many significant changes in the marine ecosystem (e.g., extinctions and radiations), which are often attributed to global changes in marine geochemistry (e.g., redox, circulation, pH and CO2). In order to develop a greater understanding of the co-evolution of life and the chemistry of the oceanic environment we wish to invite contributions from any time period in the geological record that enhances our understanding on this broad topic. We particularly encourage contributions from traditional and non-traditional isotopic systems, ranging from laboratory experiments, field studies, meta-data analysis and/or modelling.

Greenhouse gases, reactive trace gases and atmospheric aerosols levels in the troposphere are changing under a growing anthropogenic pressure with impacts on air quality, human health, and Earth’s climate. It is therefore vital to understand their sources, sinks, and physico-chemical processes that are inducing changes in their atmospheric levels and properties. Cloud–aerosol interactions remain a major obstacle to understanding climate and severe weather. Aerosol particles are subject to various complex physicochemical ageing atmospheric mechanisms modifying their properties and thereby their impacts. Furthermore, low confidence exists regarding the role of dust in abrupt climate change events over the next century.

This session aims at a broad coverage of all recent advances in novel analytical techniques, modelling, laboratory, field and satellite-based investigations in tropospheric chemistry with a focus on its oxidation capacity, covering the multi-scale physics and chemistry of aerosol formation and ageing, as well as on recent stable isotopes and radioactive nuclides geochemistry studies ranging from chemical physics investigation, analytical technique development, and their applications in nature to enhance understanding of atmospheric processes and links to changes in climate. We invite contributions of such investigations, describing a better understanding of reactive processes in all phases, and covering the physical and chemical properties of aerosol particles. We also seek contributions that develop novel analytical approaches for radioactive and stable isotope geochemistry applications covering a wide range of problems in atmospheric, Earth and planetary sciences. Laboratory, field, satellite and modeling investigations are welcome at all scales from the molecular level to global scales.

Trace elements and their stable isotopes can serve as powerful proxies for understanding the biogeochemical history of the Earth, as indicated by the biogeochemical regulations on their distribution in the modern ocean. Combinations of concentration and stable isotope data are providing new insights into their cycling, sources and sinks. Recent results from these proxies have demonstrated their potential to build mechanistic understandings of the processes driving local and global paleoenvironmental conditions. Advancements in analytical capabilities and coordinated programs such as GEOTRACES and the Sedimentary Geochemistry and Paleoenvironments Project, building global datasets from modern and paleo settings, are greatly expanding proxy potentials. These advances allow for refinement of paleoproxy applications, and the opportunity to reassess and improve some of the assumptions and uncertainties still existing.

This session aims to connect modern, paleo and methodological development communities to better integrate understandings of the present-ocean into paleoproxy applications, and to identify key uncertainties where further research is needed. We welcome contributions improving the understanding of the biogeochemical controls on stable isotope distributions including data from modern settings, from global modelling studies, from culture or leaching experiments, from studies on preservation and isolation of signals in sedimentary archives, and from novel multi-proxy approaches. We also recognize that the field of non-traditional stable isotope geochemistry requires expensive infrastructure and time-consuming analyses, facts that currently limit the diversity of scientists within it and thus the discipline as a whole. We welcome studies demonstrating good practice to increase accessibility, diversity, equity, and inclusion of the field.

Ocean circulation, the global carbon cycle and climate are intimately linked through regulation of atmospheric CO₂ on various timescales and during time intervals ranging from the Anthropocene, the Cenozoic Era or deeper in Earth history. Significant advances over past decades have been made in reconstructing key parameters of the carbon and climate systems, such as atmospheric CO₂ variations, biogeochemical cycling and ecological changes, (sub-)polar ocean dynamics and global ocean circulation, as well as the links and interactions between them. What is lacking, however, is a holistic view on these aspects of the Earth’s system and a quantitative assessment of the impacts of these climate drivers. This session brings together geochemists that promote significant progress in our understanding of the role and connections between the lithosphere, hydrosphere, atmosphere, and biosphere for Earth’s climate and the carbon cycle in the geological past, covering aspects including high-to-low latitude linkages, deep and intermediate water formation, nutrient utilization in the surface ocean, water column density stratification, role of sea ice, wind forcing, drivers of atmospheric CO₂ change, seawater composition, the diversification and expansion of flora and fauna, silicate weathering and sulfide oxidation as well as shifts in the carbonate system. We particularly welcome contributions on new proxy archives and methodology searching for higher spatial or temporal resolution or pushing the boundaries back into geological time, as well as submissions across a broad range of spatial scales and disciplines using numerical simulations and/or proxy observations.

The Cenozoic Era spanned profound and coupled changes in Earth's climate, biogeochemistry, and global ecology. Among many important transitions, the Cenozoic witnessed global cooling and a long-term decline in atmospheric pCO2, secular shifts in the isotopic and elemental ratios of major ions in seawater, the diversification and expansion of mammalian taxa, changing fluxes from silicate weathering and sulfide oxidation, and a global deepening of the carbonate compensation depth. This session seeks to bring together researchers studying connections among such changes in the Earth system, using the Cenozoic as a case study in which to explore links between the lithosphere, hydrosphere, atmosphere, and biosphere.  We welcome submissions across a broad range of spatial scales (microscopic to global), approaches (isotopic, genomic, theoretical, numerical), samples (rocks, fossils, modern and ancient sediment), and disciplines (geology, surface processes, atmospheric chemistry, biological/chemical/physical oceanography, marine/terrestrial ecology, geobiology). Overall, we solicit all contributions that address connections between the long-term changes that occurred during the Cenozoic or which use Cenozoic climate change to elucidate the positive and negative feedbacks which preserve planetary habitability across geologic time. We especially welcome submissions from early-career researchers and under-represented scientists.

Hydrothermal vents release water with substantially different chemical composition to that of seawater. Mixing of seawater and hydrothermal fluids enriches seawater with a variety of elements whilst simultaneously resulting in the removal of others, playing a key role in the biogeochemical cycles of micronutrients such as trace metals. Physicochemical and biological processes occurring within and around the plume result in further compositional changes. To advance our understanding of how hydrothermal venting alters ocean biogeochemistry, we invite presentations that describe the transport of dissolved and particulate elements and their complexing agents in hydrothermal plumes, and their effect on adjacent water masses and sediment. We particularly encourage presentations that attempt to unravel the mechanisms behind the long-range transport of elements derived from hydrothermal sources, removal of elements by hydrothermal particles and potential contributions of hydrothermal plumes to ocean productivity.

Over the past two decades, carbonate clumped-isotope geochemistry has seen a steady stream of methodological improvements driven by concerted community efforts to address various vexing analytical issues. The latest outcome of this long-term endeavor is the definition of a new reference scale for carbonate Δ₄₇ measurements (InterCarb - Carbon Dioxide Equilibrium Scale, or I-CDES) which resolves long-standing inter-laboratory discrepancies, apparently unifying calibrations of calcite Δ₄₇ thermometry. As a result, many would agree that carbonate clumped isotopes have grown out of their awkward teenage years and are now poised to offer substantial contributions to many other research fields. At the same time, “dual” measurements of Δ₄₇ and Δ₄₈ are beginning to provide new insights into the mechanisms responsible for isotopic disequilibrium and open up new applications.

This session aims to showcase new, impactful applications of Δ₄₇ and/or Δ₄₈ measurements to various research fields such as marine and terrestrial paleo-environment reconstructions; diagenesis and fluid circulation in the crust; the physiology of extinct or extant species; the long-term cycling of elements in Earth's reservoirs; thermochronology and the thermo-mechanical properties of the upper crust; the sources and sinks of various greenhouse gases; hydrology; meteoritics and planetary sciences. The session intends to illustrate what clumped isotopes bring to the table of the wider scientific community; its target audience thus includes researchers with or without previous knowledge of clumped isotopes.

Life has co-evolved with its environment for billions of years of Earth history. For instance, the rise of complex animal life on Earth has been linked to the oxygenation of the ocean-atmosphere system, which in turn is impacted by nutrient cycling and tectonic forcing. Furthermore, the Phanerozoic, spanning the last ~540 Ma, witnessed many perturbations to marine ecosystems, including five mass extinctions and biodiversification events in the ocean, which are often attributed to changes in marine redox, ocean circulation, weathering and climate. Quantifying the mechanisms underlying these environmental perturbations through time is of great interest, but our understanding in most cases remains qualitative, and many questions have yet to be answered concerning the timing, mechanisms, feedbacks and causalities associated with these environmental and biological changes.

In this session, we are soliciting contributions from the latest research focusing on the (co-)evolution of biological, geological, chemical and physical processes through Earth history. We welcome submissions using novel geochemical methods, including non-traditional elements/isotopes, and “non-traditional” uses of traditional tools such as light stable isotopes, organic biogeochemistry, laboratory experiments, big data and modelling approaches.

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Seafloor hydrothermal systems are crucial for the marine environment as they return buried substances, including metals and dissolved gases, from the Earth’s interior to the seafloor and thus, over geologic times, control the composition of seawater and provide essential elements to the biosphere. Process understanding of the fate of hydrothermal products and discharges can be used as tool for answering questions around the controls of hydrothermal systems and their evolution and activity over time. In addition, even in larger distance to vents, hydrothermal input can constitute a significant trace metal supply and can impact the sedimentary environments and biogeochemical cycles.

This session will explore the fate of hydrothermal products and discharges proximal and distal to hydrothermal sources, the diagenetic and microbial processes they undergo after deposition and the impact these processes have on the surrounding marine environment. We invite observational, experimental and modelling contributions, new approaches and new methodologies for shallow and deep hydrothermal systems from present and past times. We encourage submissions that will give new insights into processes and activities of the evolution of a hydrothermal system, spatial distribution and fluxes of products and discharges and the diagenetic alteration of hydrothermal products.

Geochemical techniques are becoming ever more necessary in our search to understand the natural history of atmospheric and ocean carbon dioxide (CO₂) on Earth. As we have surpassed the CO₂ levels recorded by the continuous ice core records over the last 800 000 years, we need to explore new proxy archives and methodologies in the geological past to understand climatic drivers and responders in a high CO₂ world. Records of old and disturbed (or ‘blue’) ice, the carbon isotopic composition of biomarkers, and the isotopic composition of calcite (notably boron), and of other minerals have all shown great promise to record past CO₂ concentrations, but each comes with limitations and inherent uncertainties. Improvements to geochemical precision and proxy understanding is key to achieve multiproxy agreement and consensus when the analyses themselves, or crucial age model constraints rely, on geochemical methods. In this session we invite new and existing contributions to the development, improvements, and collation of geochemical techniques to understand the ocean-atmosphere carbon reservoir through geological time. These include but are not limited to: new records of atmosphere or ocean CO₂, both in and out of equilibrium, new proxy archives and methodology searching for higher spatial or temporal resolution or pushing the boundaries back into geological time, geochemical modelling studies, and broad perspectives from the databases which cover growing sections of geological time.

The ability of calcium carbonate minerals to record many key parameters of the environment from where they grow makes them a critical archive of past ocean conditions. However, calcifying organisms exert physiological control over their geochemistry, which may also evolve during and after the death of the organism.  As a result, the recorded signals are usually a convolution of seawater and porewater chemistry. On one hand, inorganic calibrations and numerical calculations allow us to better assess the paleoenvironmental signals recorded by carbonates. On the other hand, the still insufficiently understood role of physiology leads to uncertainties in how carbonate biominerals respond to environmental change and record paleoenvironmental conditions. The difficulty to precisely evaluate the diagenetical alteration has led to include more and more geochemical and petrographic observations on both modern and ancient carbonate platforms to assess this question. To improve our ability to accurately interpret biomineral geochemistry as proxies, key questions must be addressed. How comprehensive is our understanding of the inorganic and physiological processes governing carbonate mineral growth and their impact on proxies? Can we develop new or improve established proxies? To what extent can diagenesis be assessed and be used as a source of paleoenvironmental information? This session aims to cover the full range of investigation on paleoenvironmental reconstructions based on carbonate geochemistry. We welcome contributions based on existing or new methods, combining diverse approaches (culture or inorganic experiments, investigations on modern or past environments) to improve our understanding of the use of carbonate minerals in paleoenvironmental investigations.

The element Si, in its various forms, is critical for the carbon, nutrient and biogeochemical cycles of the Earth. Dissolution of primary silicate minerals in metamorphic and igneous rocks consumes substantial amounts of CO₂ (i.e. silicate weathering) and serves as a long-term climatic buffer. Dissolution of silicate minerals starts on land and continues into the ocean until well below the sediment-water interface. Altogether, dissolved silica released from silicate dissolution is taken up by diatoms - a siliceous phytoplankton primarily produces O₂ on our planet, to form their tests. The burial of their siliceous bodies, induces clay formation that returns CO₂ to the ocean and may offset the effect of silicate weathering. Through continuous efforts over the past decades, critical processes within the global Si cycle have been identified with reaction kinetics, to some degree, quantified. Nonetheless, substantial knowledge is urgently needed to better answer the following questions: How are the different silicate alteration processes (e.g., clay formation, dissolution of silicate minerals and biogenic silica) coupled? How significant are these processes in the global oceans today and throughout geological time? How do they affect our ability to interpret the marine microfossil archive? How do these processes pose feedback to other components of the Earth system (e.g., climate and biosphere)? This session aims to open discussions of these questions by gathering contributions from field and laboratory observations in the ocean and sediments, regional and global modelling assessments, as well as estimates of past, current, and future scenarios.

Marine authigenic minerals (e.g., glauconite, illite, celadonite, K-feldspar, calcite, dolomite, quartz) can form either on the ocean floor through direct precipitation from seawater, or in the sub-surface within marine sediments and oceanic crust, precipitating as a result of chemical exchange with seawater-derived porewaters and aquifer fluids. The formation of marine authigenic minerals plays a major role in global elemental and isotopic cycles and can have a profound impact on the chemistry of seawater. Equally important, authigenic minerals also provide valuable archives of paleo-seawater and/or marine pore-fluid compositions. As such, it is crucial that we better understand the mechanisms controlling the formation and preservation of marine authigenic minerals through time, which will improve our ability to interpret these archives. A range of metal isotope systems (e.g., Li, Mg, Si, K, Ca, Fe, Tl) have emerged as proxies of silicate authigenesis in marine environments. Commonly incorporated into marine authigenic minerals, these “non-traditional” isotope proxies have now been leveraged in studies of the chemical evolution of seawater and global elemental cycling on geologic timescales, with great promise.

This session aims to bring together a wide spectrum of research activities related to marine authigenic minerals. We encourage submissions that combine elemental/isotope measurements with various analytical and numerical techniques, such as crystallographic studies, use of MS/MS approaches, and mass balance modelling. We particularly invite contributions that cover emerging research topics such as dating of authigenic minerals, reverse weathering and its influence on global CO₂ budgets, and the application of new metal isotope proxies.

Given the essential role of trace metals on regulating ocean carbon production and marine biodiversity, their ocean cycling has been extensively studied over the past few decades. Observational datasets of trace metals’ concentrations and distributions have rapidly increased and ocean biogeochemistry models have routinely included representations for trace metal cycling in their components. However, our understanding of the impact of small-scale physical processes (e.g., submesoscale (<10km) and mesoscale (<100km) circulation, turbulent mixing, and sea-ice transport and melting) and its interaction with atmospheric events (e.g., aerosol deposition, precipitation, and wind storms) on the distribution of trace metals is limited due to the sparsity of process studies.  Moreover, ocean models employed to study the cycling trace metals are often on the scale of > 100km,  thus effectively ignoring small-scale physical processes and their interactions with regional events.

In this section, we invite contribution from studies focusing on: 1) how the atmosphere supplies trace metals to the ocean; 2) how small-scale physical processes transport trace metals from their sources across ocean boundaries and gradients; 3) how these physical transports respond to climate changes and variabilities; and 4) how the ensemble of these processes ultimately alters ocean carbon production.

The submission of multidisciplinary studies is welcomed, including but not limited to: high-resolution ocean modeling, marine geochemistry, aerosol chemistry, time series-based and processes-based studies. Studies focusing ocean regions where the availability of trace metals is limited and where ocean dynamics are active (e.g., Eastern Boundary Upwelling Systems and high-latitude regions) are particularly encouraged.

As global CO₂ emissions continue to rise, the marine carbon cycle is in the spotlight of scientific, societal, economic and political discussion alike. In this context, marine sediments are (as they have been through Earth history) an important but chemically complex carbon sink. The role of marine sediments as a carbon store and bioreactor has been studied for decades, yet new research is continuously emerging that highlights the diversity of processes and reactions facilitated by the sedimentary environment. This includes, to name a few, land-ocean carbon transfer; depositional energy or productivity; changes in bottom water redox conditions or burial efficiency; transfer of organic carbon to authigenic carbonates; submarine weathering and reverse weathering; fundamental aspects of organic matter association with inorganic phases; organic matter sulfurization; links between microbial communities and sediment properties or lithology. This sessions invites submissions investigating any aspect of the “bottom end” of the marine carbon cycle. We welcome work from the large-scale C cycle (and the cycles of associated elements) to nano-scale analyses using state-of-the-art techniques. We encourage studies based on new data (experimental or natural systems) and on numerical models to be submitted to this session. Fundamental studies that create links to aspects of modern climate change or applied aspects of carbon sequestration are particularly invited.

Session description: Oceanic hydrothermal systems not only host a unique habitat for living organisms, but also play an important role in carbon and nutrient cycling in the subsurface, seawater, and atmosphere. (Geo)chemical transformations of organic molecules in hydrothermal fluids provide energy and carbon sources to the biosphere, through both the synthesis and degradation of organic carbon as influenced by water-rock interactions at elevated temperatures and pressures. To improve our understanding of these complex organic geochemical processes, we invite research contributions across different disciplines including but not limited to chemistry, geochemistry, geobiology, mineralogy, and petrology. Molecule-level studies on reaction pathways and mechanisms of organic carbon, and organic-mineral interactions under relevant hydrothermal conditions are also encouraged. Modeling, laboratory experiments, and field measurements are all welcomed.

Proxy elements as Ba,V, U, Mo and their isotopes are important tools for paleo reconstructions. Nonetheless many aspects of their behaviour in oceanic processes and cycling are not fully understood. All of these tracers are in some way involved in biogeochemical processes and are related to organic matter formation and cycling, and most of them are sensitive to environmental, i.e. oxygenation, conditions. Hence, their dynamics are closely linked to biogeochemical processes and redox conditions in the water- and sediment- column. Furthermore, all of these tracers have a provenance-related detrital component beside the dynamic, biologically involved component. It is only the latter that is required for their use as proxy for paleo-environmental studies, making disentangling of these components an essential step.

Rapid climate change is thought to lead to a large-scale oxic-to-anoxic transition in oceans and sub-basins with potential catastrophic consequences for ocean life. There are several paleo-manifestations in sedimentary sequences of such dramatic paleo-environmental changes. An improved comprehension of the behaviour of Ba,V, U, and Mo and their isotopes in such paleo-records and in present-day dynamics and governing processes will result in a deeper understanding of paleo-environmental conditions in present and past. Recently, isotopes from these proxies have been shown as particularly promising tools to distinguish between prevailing processes. Along with concentration data these will provide new insights not only on their cycling and processes, but also on sources and sinks. Hence, we invite contributions integrating aspects for these proxies including their cycling under various present or past environmental conditions.

The sources, sinks, transportation, and physico-chemical transformation of greenhouse gases, trace gases and atmospheric aerosols are key processes of the earth atmosphere that play important roles in air quality, human health, and Earth’s climate. Stable isotope composition analysis is a useful tool that may allow for an understanding of trace gas and aerosol dynamics at a process level. Recent advances in modeling, laboratory, field and satellite based isotopic investigations have also emerged to enhance our understanding of atmospheric processes and links to changes in climate. Developments of stable isotope measurement allows a deeper understanding of Earth’s biogeochemical cycles of and potentially astrobiology. The inclusion of radioactive nuclides (e.g., 14C and 35S) in isotope measurements has also added a new arrow to the quiver of tracing atmospheric, hydrological, and environmental processes using traditional stable isotopes (e.g., 13C and 34S). This session will focus on recent stable isotope geochemistry studies ranging from chemical physics investigation, analytical technique development, and their applications in nature. We invite contributions from researchers utilizing radioactive and stable isotopes in the fundamental principle and application of in the laboratory experiments, field measurements, and/or modeling simulations. We also seek contributions that develop novel analytical approaches (e.g., HR-IRMS, MC-ICP-MS, SIMS, NanoSIMS, TDLAS) for new stable isotope geochemistry applications. In particular, we encourage submissions that use isotope to solve a wide range of problems in atmospheric, environmental, earth and planetary sciences.

Due to its remoteness, the Southern Ocean remains, to date, poorly sampled, and this is especially true for the trace elements and their isotopes. This paucity in data renders difficult a comprehensive view of the Southern biogeochemistry, in particular, the sources, sinks and processes controlling vital micronutrient distribution in the SO remain, to date, a black-box.

Partly filling this gap, between January and march 2021, the South West Indian Geotraces Section (SWINGS), as part of the international GEOTRACES program, allowed the collection of more than 8000 samples dedicated to the quantification of physical and chemical parameters on board the N/O Marion Dufresne (MD229, GEOTRACES section GS02, Jan 11th-March 8th, 2021).

We therefore invite contributions to this session presenting the first results of this cruise, but also other relevant cruises held in the Southern Ocean, which will contribute to 1) establish the relative importance of sedimentary, atmospheric and hydrothermal sources of trace elements and isotopes (TEIs) in the Indian sector of the SO  2) investigate the drivers of the internal trace element cycles: biogenic uptake, remineralization, particle fate, and export, and 3) quantify TEI transport by the Antarctic Circumpolar Current and the numerous fronts at the confluence between Indian and Atlantic Oceans

The sulphur isotopic composition of marine sediments (e.g., evaporite minerals, carbonate-associated sulphate, barite, pyrite) have been routinely used to study the nature and evolution of the Earth’s sulphur cycle. The isotopic composition of seawater sulphate is largely controlled by the relative magnitude and isotopic composition of sulphur fluxes in and out of the ocean reservoir. Thus, the isotopic analysis of sulphur-bearing phases within marine sediments can provide, for example, an insight into palaeoweathering rates, volcanic outgassing, relative burial rates for oxidised and reduced sulphur species, and the Earth’s carbon ocean-atmosphere cycle. For this session, we invite contributions concerning all aspects of the sulphur cycle (e.g., analytical techniques, diagenesis, biogeochemical modelling, experimentation) in ancient and modern marine environments.

Tropical and deep-dwelling coral species are important archive to study past ocean dynamics through proxies. Seawater properties are recorded through tracers largely independent of calcification such as radiocarbon and radiogenic isotopes, while other proxies such as stable isotopes, fluid inclusions, rare isotopes are significantly impacted by how the organism transfers seawater geochemical properties into the skeleton. In this session we thus welcome all contributions which study present past climate and ocean dynamical features throughout the Quaternary (or even older) based on records of corals. We welcome studies providing new insight in proxy calibration, novel trace isotopes, as well as revision of seemingly well-established proxies. Moreover, we welcome contributions that demonstrate climate variability and ocean dynamics on absolutely dated time scales from the distant past to the sub-annual records of the post-modern area. Feel free to also submit contribution on the precision dating of coral archives and the reconstruction of coral ecosystem dynamics related to their growth.

Non-traditional stable isotope ratios are powerful tools for enhancing our understanding of the biogeochemical history of the Earth and its oceans. Advancements in analytical capabilities, improvements in chemical leaching protocols to target specific phases, and coordinated programs building global datasets from modern and paleo settings, such as the International GEOTRACES program or the Sedimentary Geochemistry and Paleoenvironments Project, are greatly expanding the potential of applying these proxies to study biogeochemical cycling through time. These advances allow for refinement of paleoproxies, a more precise approach to paleoproxy applications, and the opportunity to reassess and refine many of the assumptions and uncertainties of the pioneering non-traditional stable isotope studies. This session aims to connect modern, paleo and methodological development communities to better integrate modern understandings into paleoproxy applications, and to identify the key uncertainties where further research is needed. We welcome contributions improving the understanding of the biogeochemical controls on stable isotope distributions including data from modern settings (e.g. ocean section or profile datasets), from global modelling studies, from culture or leaching experiments, from studies on preservation/fidelity and isolation of signals in sedimentary archives, and from novel multi-proxy approaches. We also recognize that the field of non-traditional stable isotope geochemistry requires expensive infrastructure and time-consuming analyses, facts that currently limit the diversity of scientists within it and thus the discipline as a whole. We welcome studies demonstrating good practice to increase accessibility, diversity, equity, and inclusion of the field.

Polar regions not only play a particularly important role in global climate change over millennial to glacial-interglacial timescales, but are also extremely sensitive to these changes. Variations in deep ocean circulation and biogeochemistry driven through polar or subpolar processes may for example have substantial consequences for deep ocean oxygenation or the global carbon cycle. An in-depth understanding of past changes in deep ocean circulation and polar biogeochemistry is important for improving process-level understanding of the complex climate system so that future responses of the Earth system to anthropogenic forcing can be better represented in numerical models. Despite decades of study and much advancement in our understanding of climate proxies and modeling efforts, our knowledge about how deep ocean circulation and ventilation in the polar and subpolar oceans have affected Earth’s past climate change and carbon cycle remains understudied. 

This session invites contributions on all aspects of past climate research related to the (sub-)polar regions and the role it plays in Earth’s system, including teleconnections, high-to-low latitude linkages, deep and intermediate water formation, nutrient utilization in the surface ocean, water column density stratification, role of sea ice, and the westerly winds. We welcome studies based on marine sediments or other marine archives, ice core records, modeling results, and the integration of proxies in models. The time frame aimed for this session is the Cenozoic although longer records will also be considered. Multi-proxy paleo-reconstructions, model-data comparisons, and studies providing constraints on the future evolution of climate under anthropogenic forcing are particularly encouraged.

Changing oceans due to natural and anthropogenic phenomena, like vulcanism (hydrothermal) and ocean acidification, partake in a wide range of physical and biogeochemical processes. These processes, including oxidation-reduction, complexation, precipitation, etc., directly affect metal speciation and residence time in seawater. It is important to compare studies using multi-disciplinary approaches to know the effect of these reactions on the trace metal physico-chemical processes and biogeochemistry. These reactions play a crucial role in the marine biogeochemical cycle of trace metals and are essential for understanding the response of future oceans and the ecosystems. Accordingly, this session aims to congregate researchers willing to present their research further improving the knowledge in this area.

We encourage contributions relating to analytical tools, modelling approaches, laboratory-based experiments and in-situ observations about marine trace metal biogeochemistry, and physico-chemical properties in environments ranging from vulcanism to ocean acidification prone regions.

Particle-reactive elements, such as rare earth elements (REEs), Th, Pa, Pb, Po, Be and their isotopes are powerful tracers for investigating the ocean biogeochemical cycles and can be applied to track e.g. continental input, ocean circulation and particle flux. For their robust applications across space and time, it is essential to obtain a comprehensive understanding of the physical-chemical processes controlling the behaviors of individual particle-reactive elements. Some key processes include exchange at ocean interfaces via e.g. rivers, atmospheric fallout and benthic dynamics and internal cycling via e.g. scavenging and remineralization that can depend on particle types and fluxes. Such knowledge can not only provide significant insights into the debate on the top-down versus bottom-up control of ocean chemistry in the modern times, but also help to resolve the debate arising from conflicting records of multiple particle-reactive isotopic systems in the geological past.

This session invites observational, experimental and modelling contributions on the distribution, flux and controls of particle-reactive elements from estuaries to open ocean. Note that studies on other elements with a high particle-affinity are also welcome as they can be controlled by processes of interest. Multi-disciplinary and multi-proxy studies and contributions on advances in geochemical proxy development are especially encouraged. This session focuses on processes and fluxes in the modern oceans, but submissions on paleo-oceanographic and paleo-environmental reconstructions are also of interest. Early career scientists are particularly encouraged to contribute to this session.

The composition of the troposphere is changing under a growing anthropogenic pressure. It is therefore vital to provide a scientific sound understanding of the physical and chemical processes that are inducing such changes, with aerosols being the largest sources of uncertainty in the atmospheric systems. Aerosol particles are of diverse nature and are partly produced via a series of complex gas phase processes that are currently being unraveled using novel analytical techniques. Once airborne, aerosol particles are subject to various complex physicochemical ageing mechanisms leading to many modifications of their size, composition, morphology, and properties, including among others optical, and chemical properties. Particles’ hygroscopicity, ability to act as CCN, and cloud–aerosol interactions remain a major obstacle to understanding climate and severe weather. Finally, there is low confidence regarding the role of dust in abrupt climate change events over the next century.

This session aims at a broad coverage of all recent advances in tropospheric chemistry with a focus on its oxidation capacity, covering in the multi-scale physics and chemistry of aerosol formation and ageing. This session, therefore, invites contributions presenting new advances in analytical chemistry, describing a better understanding of reactive processes in all phases, and covering the physical and chemical properties of aerosol particles. Contributions are encouraged to cover a wide range of activities, from field observational data, laboratory research, to modeling at all scales from the molecular level to global scales.

We invite poster submissions demonstrating how trace element and isotope data, together with nutrient, oxygen, hydrographic and BioGEOTRACES data from the GEOTRACES Intermediate Data Product (IDP2021) are being used to understand the biogeochemistry of the oceans. You might have used GEOTRACES data to quantify or constrain the input, internal cycling, and removal processes that ultimately control the global distributions of trace elements and isotopes (TEIs), especially those that are involved in biological cycling processes. You might have used GEOTRACES data in your teaching or outreach efforts, and we definitely solicit reports from those activities. We imagine a collegial and convivial session where we can enjoy learning more about the various ways GEOTRACES data are being utilized.

There are significant barriers to the implementation and progression of education and outreach activities, particularly in the practical aspects of how to begin creating a diverse network and in co-creating and designing the activities. These barriers are especially apparent, for example, where fieldwork and research are performed and for early career researchers (ECRs) setting up new connections. This workshop-style session has two parts. The first part will bring together expertise from across the world to explore practical (rather than theoretical) ways of executing meaningful and impactful activities. Several experts (or “big issue” guides) will facilitate interactive discussions surrounding outreach with a variety of different communities. Topics of discussion may include co-creating decolonised outreach activities, engaging with indigenous communities, creating activities that capture students and/or communities from low SES backgrounds, disability-inclusive outreach and education, and using newer, less traditional mediums (podcasts, film, social media, etc.). Experts will lead smaller group discussions during this interactive workshop-style session and share how they engage with communities, including lessons learned, and encourage participants to share their experiences during outreach. At the end of this part of the session we will come together, and each facilitator will share the ideas and practical solutions discussed in their groups. The second part is a poster session where submitters can highlight their own efforts relating to outreach people are attempting to start, are currently engaged in, and/or are trying to progress. Poster submissions will also shape the specific topics and issues that experts will discuss during this workshop-style session.

This workshop is designed to enable those engaging or wanting to engage in outreach to connect and discuss practical issues and solutions. Participants will be able to engage our Big Idea Guides during a panel discussion and in smaller breakout groups will be able to discuss ideas, issues and solutions around outreach they are interested in. Key takeaways will then be shared with all groups at the end of the session.

Our Big Idea Guides:

Dr. Aileen L. Doran: Equity, Diversity and Inclusion in Geoscience (EDIG) project aims to be a platform that enables open communication about challenges in geoscience to help make it more inclusive, equitable and accessible.

Professor Sumit Chakraborty: President of the Geochemical Society, will reflect on initiatives taken by the Geochemical Society under his leadership and into issues faced by geoscience outreach and our community on a larger scale.

Dr. Melanie Finch: Increasing inclusion of neurodiverse students in geosciences.

Professor Anthony Chappaz: Professional development - bridging academia to outside communities by developing skills and strategies around communication and networking not generally taught in academic settings.

Part 2 of this workshop is a poster session, where attendees will have the opportunity for in-depth discussion about posters that communicate issues, ideas, and practical solutions for more effective outreach.

Working with data over the years results almost inevitably in self-made code snippets, scripts or spreadsheets, and sometimes even full-fledged programmes that optimise workflows, reduce workload and significantly speed up daily tasks. Some of them make it to the public but most remain invisible, hidden behind the outcomes of the research they are helping with. However, many of them are not shy but did not have the possibility to shine, yet. We provide a spotlight for them, so that the scientific community may benefit. We welcome presentations about all kinds of self-made software that facilitate our research. The presented tools can be written in any programming language and be in any stage of their development. We aim to raise awareness of what is already out there, to facilitate sharing of the tools and to foster collaborations for their development.

This live event includes sessions 14cO2 and 6gO2, in that order, with no break between them.

We invite submission of experiences and materials for engaging with and communicating geochemistry to non-scientific audiences: general public, schools, the media, policymakers, and other stakeholders. Geochemists and scientists in general, are very often faced to the challenge of communicating and sharing their knowledge to different audiences in a way that it is understandable to them.

This session has the double purpose of showcasing examples which could serve as source of inspiration and at the same time highlight effective strategies that geochemists could follow to successfully engage with a non-scientific audience.

Geochemistry is a uniquely varied discipline, spanning Chemistry, Earth, Planetary and Environmental Sciences. However, this disciplinary diversity comes with unique challenges to fostering a diverse and inclusive community, partly linked to inequitable access to resources and the combination of lab-, field- and office-based approaches that geochemical research requires. In this session, we invite presentations that assess the obstacles that contribute to the under-representation of marginalized groups within geochemistry and that suggest best practices and innovative ideas to remove those obstacles. Topics may include, but are not limited to: data relating to professional representation (e.g., in awards, medals, grants, graduate programs, high-level positions, invited talks, papers, journal editorships); evidence of barriers to inclusion, personal, institutional, or cultural; and novel strategies and best practices to identify and overcome these barriers (e.g., mentoring, networks, funding, institutional initiatives, national or international policies or schemes). Abstracts to this session will be free of charge and will not prevent the submission of an abstract to another theme as presenting author.

Geochemistry was not born yesterday. For example, the multiplication of advanced analytical tools that make our daily work so fascinating in 2022 result from centuries of incremental or transformative technological innovations, as well as from a succession of conceptual advances in the fields of physics, chemistry, Mathematics and Ecology. Those roots tend to be forgotten, and this is detrimental to the quality of our science, and our understanding of it. This session aims to explore the historical roots of geochemistry along two main directions. First, a direction where geochemistry is conceived as a practical science based on advanced analytics, which are only the outcome of centuries of creative technological inventions, developments and measurements. Secondly, geochemistry as a conceptual framework inheriting centuries of advances in the understanding of the structure and properties of matter, light, and other critical concepts of the geological sciences in general. All contributors who want to share with us their insights on the historical roots of our science and their pedagogical implications are welcome. A priority, if needed, will be given to early career scientists without discrimination for institution, race, etc.