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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.