The current architecture of the Solar System results from the chaotic evolution of the protoplanetary disc. Understanding the origin and evolution of dust and early planetesimals in the first few million years while the solar nebula was still active is critical in constraining the accretion history of planets. This endeavour strives on interdisciplinary research that brings concepts and models together enabling to decipher the meaning of cosmochemical and astrophysical observations.

In this session, we invite contributions on observations, experiments, calculations, statistics and modelling of protoplanetary discs. We particularly welcome investigations of samples returned from asteroids, meteorites and their components (petrology, chronology, elemental, nucleosynthetic and stable isotope compositions etc.), experiments and calculations of the evolution of early-formed objects (condensation, evaporation, chondrule formation etc.) and astrophysical observations, simulations, and models for the Solar and extrasolar systems (stellar nucleosynthesis, protoplanetary disc dynamics and composition, planetary formation etc.).

The detection of more than 6,000 exoplanets has transformed planetary science into a truly comparative discipline. Observations from the JWST, ALMA, and next-generation ground-based facilities now provide detailed constraints on the compositions, atmospheres, and host stars of distant worlds. Among them, super-Earths and sub-Neptunes are the most common types of planets, yet they have no direct analog in our Solar System. How does chemistry shape this extraordinary diversity of planets? Addressing that question requires the combined expertise of astronomers and geoscientists who can link observational data to the chemical and physical processes that control planetary formation, differentiation, and the evolution of surfaces and atmospheres.

In ~100 million years, a cloud of gas and fine dust transformed into our Solar System through numerous processes from formation of the earliest solids to planetary differentiation and giant impacts. We invite contributions that illuminate this critical interval using natural samples (meteorites, micrometeorites, other dust particles, and mission returned samples from Moon, Itokawa, Ryugu, and Bennu), experiments (high-temperature/-pressure melting, diffusion, impact processing, isotopic fractionation and evaporation), and simulations and models (dynamics of accretion, thermal evolution, magmatism, and volatilization, transport mechanisms).

The return of lunar samples at the end of the 1960s set the stage for groundbreaking discoveries about the origin and evolution of not only the Moon, but the solar system more broadly. It also prompted the development of essential curation tools and techniques to preserve these important samples in pristine condition. Over the past five decades, we have returned more samples from new regions of the Moon, but also from different solar system bodies including a comet, the Sun, and asteroids Itokawa, Ryugu, and Bennu. Together with other astromaterials collections like meteorites, the analysis of these samples has furthered our understanding of the diversity of building blocks of our solar system, the formation and evolution of the terrestrial planets, the origin of life on Earth, and timescales of solar system processes. The enormous scientific return of these collections has been enabled directly by their careful curation and distribution to the scientific community. Looking forward, potential sample return from Mars and the lunar South Pole will provide new opportunities and challenges for astromaterials curation and analysis. Topics for this session will include advances in curation technologies, sample handling, laboratory best practices, and data archiving for extraterrestrial materials collections. In addition, we welcome geochemical, isotopic, and mineralogical analyses of returned samples or samples planned for return to Earth, studies linking remote sensing observations and laboratory analysis, and recent advancements in analytical techniques.

Throughout the Solar System, planetary bodies witness complex magmatic, volcanic and surface‐alteration processes, from the earliest stages of differentiation to present‐day resurfacing and volatile exchange. This session invites contributions that explore magmatism, volcanism, crust–mantle–surface coupling, melt–crust segregation, magma ascent, emplacement and eruption, lava–flow evolution, planetary volcanology, impact‐driven melting, alteration by volatiles or fluids, surface weathering and arid or icy surface processes on comets, asteroids, the Moon, Mars, Venus, Mercury, icy moons and other planetary bodies. We especially welcome multidisciplinary studies combining sample analyses, remote sensing, petrography, petrology, geochemistry, isotopes, modelling and field analogues, that advance our understanding of how magmatic and surface processes shape the evolution of planetary surfaces and interiors.

Mantle metasomatism is a fundamental driver of the long-term chemical and thermal evolution of Earth’s lithosphere, shaping magma generation, migration, and geochemical diversity across tectonic settings. In both intraplate and convergent-margin environments, the addition of volatile-rich fluids and silicate melts to the subcontinental lithospheric mantle modifies its mineralogy, fertility, and melting behaviour, frequently giving rise to alkaline magmatism and hybrid rock assemblages. These processes help explain compositional heterogeneity from centimetre-scale veins to regional magmatic provinces.

Radiogenic isotopic systems—Sr, Nd, Pb, and Hf—provide key constraints on the origin, timing, and persistence of metasomatic imprints. Their ratios distinguish ancient lithospheric domains, recent metasomatic overprints, and contributions from asthenospheric or crustal sources. Enriched signatures commonly reflect slab-derived inputs or long-lived isolated mantle domains, whereas depleted signatures signal juvenile components. The juxtaposition of isotopically distinct domains highlights the longevity of metasomatic modification and its reactivation during subsequent tectonomagmatic events.

In convergent settings, slab-derived agents enrich the mantle wedge and promote arc magmatism through flux melting and refertilisation. In intraplate regions, alkaline magmatism often results from the reactivation of metasomatized mantle interacting with deeper upwellings. Passive-margin isotopic variability further underscores the role of metasomatic inheritance in magma genesis.

Integrating isotopic, mineralogical, and petrological data with machine-learning approaches now enables multidimensional reconstructions of igneous processes. This session invites contributions examining mantle metasomatism, alkaline magmatism, and lithospheric evolution, especially those applying artificial intelligence to decode igneous petrogenesis.

The Earth's interior—including the core, mantle, and lithosphere—plays a fundamental role in the functioning of the Earth system, directly influencing the evolution of surface habitability. In recent decades, low-temperature geochemists studying Earth's surface history and solid Earth geochemists, geophysicists, and petrologists examining the interior have tended to work in relative isolation. This section aims to bring together experts from different fields to understand the connection between deep and surface processes and deep mechanisms driving the evolution of Earth's habitability throughout geological history. We encourage submissions on topics such as the distribution and properties of volatiles within Earth's interior, the cycling and dynamics of carbon, hydrogen, and oxygen in the deep Earth, and the chemical reaction mechanisms occurring in the deep Earth and their effects on the surface. We also welcome low-temperature geochemical studies focused on understanding the evolution of Earth's surface habitability. Our goal is to unravel the mysteries of the deep Earth engine and promote significant theoretical innovations in Earth system science.

Carbon, hydrogen, oxygen, nitrogen, sulfur, and their compounds are volatile components that dominate habitable environment on the Earth's surface. However, the majority of these volatiles are hidden in the deep interior of the Earth as well as other terrestrial planets where the high pressure–temperature conditions dictate the physics and chemistry of the carriers of volatiles. Although these compounds generally account for less than 1–2% of total planetary masses, the circulation and interactions of volatiles in the deep Earth exert an outsized impact on the physical and chemical properties of minerals and rocks, and the formation of planetary habitability. These influences, in turn, profoundly shape deep interior dynamic processes, including plate subduction, mantle plume upwelling, mantle convection, and even life evolution on the surface. This session will focus on discussions of volatiles in the Earth and other terrestrial planets’ interiors. We invite contributions from the fields of geophysics, geochemistry, high-pressure and high-temperature experiments, first-principles calculations, dynamical simulations, and data-driven research with artificial intelligence techniques to foster discussions on the distribution and circulation of volatiles in the Earth and planetary interiors, as well as their roles in the physical and chemical processes.

The chemical and physical processes operating in planetary interiors govern differentiation, core formation, mantle convection, and magmatism, underpinning the evolution of terrestrial planets. High-pressure, high-temperature experiments, combined with thermodynamic and theoretical approaches, have been critical to constraining these processes and linking mineral physics with geochemistry and geodynamics. From the distribution of light elements in the metallic core to the partitioning of trace and volatile species during magma genesis and the phase transitions that define seismic discontinuities, experimental petrology has provided fundamental insights into the architecture, dynamics, and chemical evolution of planetary bodies.

Professor Bernard Wood has pioneered many of these advances. He established the foundations of modern high-pressure, high-temperature petrology and elucidated the chemical behaviour of elements in planetary interiors, including the distribution of light elements in Earth’s core. He introduced widely used thermodynamic approaches to geology, advancing understanding of phase transitions and stabilities in the deep mantle. His development of oxybarometers for the lithospheric and sublithospheric mantle greatly improved knowledge of redox processes and the deep carbon cycle. Bernard also advanced models of basalt genesis and trace element partitioning.

This session will bring together researchers from experimental petrology, geochemistry, and planetary science to celebrate Professor Wood’s extraordinary impact. We welcome contributions from the full breadth of geochemical and planetary sciences, and from researchers at all career stages and backgrounds.

Understanding the composition, structure, and evolution of Earth and other terrestrial planets’ inaccessible deep interiors requires precise knowledge of the elastic and transport properties of mantle and core minerals and melts. Accurately determining how pressure, temperature, and composition affect elastic properties is crucial for interpreting seismic observations to constrain their internal structures and compositions. Electrical conductivity studies, as a complementary tool to seismic results, provide further insights into features that may not yield strong seismic anomalies. Assessing other transport properties—such as viscosity, thermal conductivity, and diffusivity—is essential for modeling mass and heat flow in the mantle and core, and for understanding the processes that drive magnetic field generation and long-term planetary evolution. This session will focus on recent experimental and theoretical advances in determining the elastic and transport properties of deep Earth and planetary materials, and we invite interdisciplinary contributions that integrate mineral physics with geophysical observations to advance our understanding of planetary composition, evolution, and dynamics.

Diamonds are resilient, robust and direct probes of the deep Earth that extend to some of the earliest stages of Earth’s planetary evolution. Diamonds host mineral and fluid inclusions that provide crucial insights into the composition and evolution of mantle regions that are otherwise inaccessible. The carbon and nitrogen isotopic compositions of diamond continue to improve our understanding of how volatile cycling has changed throughout Earth’s history. Understanding how nitrogen and hydrogen impurities in diamond are incorporated during diamond formation, and how related defects evolve with time and temperature, is a crucial part of relating isotopic data to the types and sources deep mantle diamond-forming fluids. Diamond surface textures provide a record of mantle-derived melts and fluids percolating through the lithospheric keels of cratons. The formation of kimberlite, lamproite and lamprophyre magmas, which bring fragments of the sub-cratonic mantle and diamonds to the surface, is defined by multiple competing hypotheses regarding their composition and origin. Recent advancements in analytical, experimental, and thermodynamic and computer modelling methods have significantly expanded our knowledge of mantle processes leading to kimberlite magmatism and the formation of diamond, the inclusions they contain, and enclosing mantle lithologies. This session invites contributions from different disciplines of diamond research including studies of kimberlite, lamproite and lamprophyre magmatism, studies of kimberlite-borne mantle xenoliths and the processes that control their composition and texture, and studies of defects and inclusions in diamond.

The Earth’s primordial mantle is the original source reservoir from which subsidiary reservoirs, such as the continental crust and the depleted mantle, are derived. These reservoirs have continuously (co-)evolved from the formation of the Earth until present day leaving changes in mantle composition. Early differentiation episodes, late accretion, continental crustal extraction, and related magmatic processes have led to chemical heterogeneities of this source reservoir. Over time, these processes, along with geodynamic regimes such as subduction, mantle plumes, and metasomatism, have generated complex chemical heterogeneities in the mantle, both localized and global in scale. To understand the evolution and degassing of the mantle through time, a wide range of chemical tracers have been used to document the compositional heterogeneities, understand their origin, probe the existence of ‘cryptic’ reservoirs, and investigate the nature of crust-mantle and core-mantle boundary interactions. These include element abundances (e.g., highly siderophile elements), long-lived (e.g., Sr, Nd, Hf, Pb), short-lived (e.g., ¹⁴²Nd, ¹⁸²W, ¹²⁹Xe) and stable (e.g., Fe, Mg, Ca) isotopes. Moreover, interdisciplinary approaches integrating geochemistry, mineralogy, petrology, geophysics, mineral physics and dynamics have significantly advanced our understanding of the compositional evolution of the mantle, from the early Earth to the present day. In this session, we welcome contributions that employ cross-disciplinary approaches to explore mantle evolution and the processes that create and sustain its chemical diversity.

Over the past few decades, observations of exotic bonding behaviors, complex stoichiometries, and low-symmetry arrangements in simple and binary systems—including noble-gas compounds—have progressively reshaped our picture of Earth’s structure and evolution, as well as processes such as volcanism and tectonics. Rather than a relatively simple, uniform deep Earth that can be described as consisting of a few high-symmetry phases, we now envision a more mineralogically differentiated and chemically intricate planet, where minor constituents can play major roles. This view aligns with the heterogeneities revealed by seismology. The exotic nature of bonding and crystal chemistry that governs Earth’s inner structure and dynamics is gradually being uncovered, yet remains far from fully understood and generalized.

This session brings together experimental and theoretical studies that advance our understanding of the chemistry, bonding, and resulting physical properties of matter in planetary deep interiors, as well as the extreme-condition static and dynamic processes that shape planetary compositions and structures. These include the identification of new compounds and phases, determinations of material properties at high pressure, and investigations of bonding mechanisms under extreme conditions. We also seek contributions that articulate open problems and challenges warranting further investigation.

Deciphering high-pressure structures and properties relies on demanding and sophisticated experimental and theoretical tools. We welcome presentations on cutting-edge methods and modeling, discussions of their potential and limitations, and identification of needs for further developments.

Interfacial geochemistry governs many of the fundamental processes that drive the exchange of material and energy within the Earth’s interior. At interfaces between solids, aqueous fluids (e.g., water or hydrocarbons), and gases (e.g., H₂, CH₄, He), chemical reactions induce transformations that regulate the cycling of key elements and molecules. These interfacial processes play a central role in shaping the chemistry and dynamics of deep regions—from the lower part of the upper crust to the upper mantle—and influence the evolution of rock properties, fluid compositions, and ore-forming systems.

This session focuses on the mechanisms and consequences of interfacial reactions under high-pressure and high-temperature conditions in deep geosystems. Topics include, but are not limited to, (1) physicochemical properties of confined fluids in tight rocks; (2) interfacial and microdroplet-mediated reactions that facilitate chemical transformations, (3) the dynamics of reactive mineral–fluid interfaces that govern element transport and geochemical transformation, and (4) processes occurring in regions inaccessible to deep drilling, such as subduction zones and hydrothermal systems—all of which are crucial to the deep carbon and element cycles.

We particularly welcome interdisciplinary studies integrating geochemistry, petrology, mineral physics, and geophysics to elucidate how interfacial processes couple deep Earth chemistry with surface evolution.

Element redistribution among mineral, fluid and melt in subduction zones has strong impact on crustal geochemical diversity (including ore genesis), mantle heterogeneity and surface environment. Gray Bebout's pioneering research investigating subduction-related metamorphic rocks has significantly advanced the understanding of the behavior of volatile and fluid-mobile elements in subduction zones and their applications to trace crust-mantle interaction, deep mantle recycling and surface emission. In honor of Gray Bebout's contributions, this session invites presentations of mineralogical, petrological, geochemical and/or thermodynamic insights from field observations, laboratory experiments, theoretical calculations, modeling and machine learning into the understanding of elemental mobility, flux and fate during processes across subduction zones (e.g., source enrichment, metamorphic fluid release, deep recycling and return to the surface) and their effects on long-term evolution of Earth's subsystems at various spatial and temporal scales.

Subduction zones are the most important site of material exchange between Earth’s surface and its interior. Arc magmatism has played a key role in the long-term geochemical evolution of the Earth’s continents and atmosphere. Recent advances in high-precision stable isotope analysis have led to the emergent investigation of many novel systems in arc magmas on a whole-rock scale (e.g., K, Ca, Ba, Cu, Zn, Mo, Tl, W), as well as in-situ analysis of well-established isotope systems in melt inclusions and phenocrysts (e.g., O, H, S, Cl, B).

This session invites contributions that apply stable isotope systems to provide new perspectives on the sources and processes associated with subduction-related magmatism, with an emphasis on deep volatile cycling. We encourage submissions focused on natural samples, as well as experimental and numerical work exploring stable isotopic fractionation and mass transfer in arc magmatic systems.

Serpentinites play a pivotal role in Earth’s geochemical and geological systems, with growing relevance for sustainability and planetary science. They influence, among others, mantle melting at subduction zones and drive mass and energy transfer across the lithosphere, hydrosphere, and biosphere. The unique mineral assemblages and associated fluid chemistry changes during their formation, namely serpentinization, are central to the chemical evolution of the lithosphere. A key product of serpentinization is molecular hydrogen, which not only participates in abiotic organic synthesis but also serves as an energy source for chemosynthetic life, suggesting implications for the origin of life on Earth and potentially other planets. Serpentinites also offer practical benefits for climate and energy solutions. They naturally sequester CO₂ through mineral carbonation, contributing to carbon capture strategies. Additionally, the hydrogen released during serpentinization is being explored as a large-scale, natural resource. These rocks are also linked to critical metal deposits essential for a low-carbon economy.

In this session, we encourage interdisciplinary dialogue on all facets of this complex metasomatic process, from field-based investigations of ancient and modern serpentinite formations to laboratory experiments, numerical modelling, and cutting-edge analytical developments seeking a deeper understanding of serpentinization and its broad (bio)geochemical implications. Topics may include, but are not limited to, fluid and element mobilization, hydrogen generation, carbon sequestration, and the feedbacks between fluid-rock interactions and global geochemical cycles. Contributions from continental and ocean drilling programs are especially welcome, as are insights into the role of serpentinites in supporting early life and providing valuable metal resources.

Fluids are the main agent of chemical transport, mechanical weakening, and energy exchanges within Earth’s lithosphere. Their presence affects lithospheric architecture and rheology, influencing processes from element cycling between Earth’s surface and deep interior, to metamorphism, magmatism, mantle and lithospheric metasomatism, orogenesis, seismicity, and the formation of metal and volatile (He+H₂) resources. Fluids selectively mobilise elements from their host rocks, resulting in elemental redistribution. This produces metasomatic depletions/enrichments that create unique lithologies in subduction mélanges, as well as gems. Fluids link deep Earth processes (e.g., mantle degassing) to surface environments, and their element fractionation is key in global element cycling and planetary habitability. Their reservoirs are moreover sources of heat and storage for CO₂.

This session provides a forum to discuss the origins of fluids, their metasomatic interactions, and their impacts on the lithosphere's physico-chemical properties. We invite contributions that use thermodynamic and computational modelling, experiments, elemental and isotopic tracers, noble gases and biogeochemical tools, as well as geophysical investigations providing constraints on the presence, distribution, and properties of geofluids. We particularly encourage contributions that link the chemical and physical properties of fluids and their impacts on lithosphere evolution in time and space. We also welcome observational and modelling studies into the dynamics of production, release and reactive transport of crustal volatiles, including their applications outside academia to fluid-derived resources of (critical) metals, volatiles and energy. This interdisciplinary forum aims to advance our understanding of how fluids shape the lithosphere and, by extension, Earth’s surface environments and resource potential.

Stable isotopes, both traditional and non-traditional, have revolutionized our understanding of Earth’s differentiation, lithospheric evolution, and elemental cycling across diverse environments. Recent advances in high-precision mass spectrometry, experimental calibrations, and theoretical modeling now allow us to resolve isotope fractionation from atomic to planetary scales, offering unprecedented insights into processes that connect Earth’s deep interior and surface systems. This session aims to integrate perspectives from geochemistry, petrology, planetary science, and economic geology to explore how stable isotopes illuminate the dynamic evolution of Earth.

We welcome contributions that advance our understanding of isotope fractionation mechanisms (e.g., mass-dependent and mass-independent fractionations, equilibrium and kinetic effects, diffusion, redox transformation, and mineral–fluid/melt interactions), and their implications for quantifying pressure-temperature, source heterogeneity of natural systems, and beyond. Particular emphasis is placed on the applications of non-traditional metal stable isotope systems (e.g., K, Mg, Fe, Zn, Ca, Sr, Rb, Mo, W) to unravel crust-mantle interaction, mantle source heterogeneity, magma differentiation, core-mantle interactions, and ore-forming processes.

By integrating analytical, experimental, and modeling approaches, this session seeks to bridge the surface and deep Earth through isotopic perspectives—from core formation and mantle dynamics to hydrothermal alteration and ore formation—highlighting how stable isotope geochemistry continues to decode the complex evolution of Earth’s lithosphere and beyond.

Reconstructing the early stages of Earth’s history is severely challenged by the limited and discontinuous preservation of ancient rocks. A powerful approach to overcome this limitation is through the study of detrital minerals preserved within ancient sedimentary deposits. Recent advances in in situ geochronological and analytical techniques now allow precise characterization of individual mineral phases within detrital assemblages. When integrated with complementary geochemical data, these offer valuable insights into the Earth’s early crustal evolution.
Durable and heavy minerals such as zircon, chromite, rutile garnet, and others, commonly concentrate during sedimentation, and can be extracted from sedimentary archives to address a wide range of geological questions. By applying multi-proxy approaches to our oldest detrital rock record, we can reconstruct a comprehensive understanding of Earth’s history. This session welcomes contributions that utilize and/or improve current tools usingdetrital heavy minerals to explore fundamental questions related to Earth’s evolution, such as: 1. Crustal differentiation and reworking; 2. Evolution of mantle, melt sources and crustal growth; 3. Tracing the tectono-metamorphic evolution of terranes; 4. Tracking the magmatic-hydrothermal evolution of the crust; 5. Sedimentary processes affecting detrital records; 6. Novel petro-geochemical tools applied to detrital minerals.

Earth records a complex evolution spanning 4.6 billion years. Reconstructing the history of our planet and understanding its fundamental processes hinges on our ability to accurately establish the timing and rates of geological processes. While zircon U-Pb geochronology has traditionally been the standard tool for dating rock formation, modern geo- and thermochronology makes use of a rich landscape of analytical techniques and dating strategies. These include a plethora of new mineral-decay system pairs, allowing, for example, the application of U-Pb dating to non-traditional phases, enhancing the interpretation of dated minerals by additional material characterization, or combining of multiple geo- and thermochronometers on the same grains. These advances enhance our capacity to assign an age to specific processes that shaped Earth’s history such as crystal growth, mineral reactions, exhumation-related cooling, fluid-rock interaction, mineral-deposit formation, deformation along fault zones or the direct dating of sedimentary processes. This session invites presentations conducting methodological research in geo- and thermochronology contributing to the development of new analytical instrumentation, calibrations or age reference materials, as well as improvements in data handling and interpretation. We encourage the submission of new strategies to constrain the timing and rate of geological processes using geo- and thermochronological tools including (but not limited to) U-Pb, Rb-Sr, Lu-Hf, Re-Os, Raman, fission-track, and noble gas isotopic dating systems.

Orogenic belts and suture zones preserve the most compelling records of Earth’s tectonic evolution—from ocean closure and subduction to continental collision and post-orogenic reworking. This session examines the spatiotemporal evolution of these tectonic systems and the crustal processes that shape them. We aim to integrate structural, petrological, geochemical, geochronological, and geophysical approaches to unravel the dynamics of subduction, collision, magmatism, metamorphism, and crustal deformation through time. Contributions addressing the interplay between deformation mechanisms, metamorphic reactions, and crust–mantle interactions in both fossil and active orogens, with a special emphasis on the Himalayan orogeny and other global analogues, are particularly encouraged.

We invite studies that reconstruct pressure–temperature–time paths, quantify cooling or exhumation rates, or elucidate the role of deep-crustal fluids in deformation and metamorphism. Research employing advanced analytical methods (e.g., grain-scale microstructural analysis, thermodynamic modeling, isotope geochemistry, and geochronology) and those linking lithospheric processes to surface evolution (erosion, sedimentation, and climate–tectonic feedback) are welcome. By bridging modern and ancient mountain systems, this session seeks to foster a holistic understanding of how suture zones and orogenic belts record crustal growth, lithospheric recycling, and the formation of economic resources—ultimately providing insights into the geodynamic mechanisms that have shaped continents from the Archean to the present.

The earliest stages of Earth’s lithospheric evolution were marked by dynamic transitions in the nature of magmatism, metamorphism, and crust–mantle interactions that set the stage for long-term planetary habitability. Recent advances in petrology, geochemistry, diffusion chronometry, geochronology, microanalytical techniques, and numerical geodynamics now allow us to extract not only the thermochemical and mechanical conditions of the Earth’s early lithosphere but also the timescales of heat, mass, and fluid transfer in high-temperature regimes, and to link these to the larger-scale geodynamic evolution of the Hadean-Archean–Proterozoic Earth.

This session invites contributions that address lithosphere dynamics on the early Earth. Priyadarshi Chowdhury’s research has made high-impact contributions to first-order problems in lithosphere dynamics, and this honorary session will address key topics including: the chemical composition of continental crust across time, the rates, timing, and processes of early continental crust formation; the temporal character of tectonothermal events under hotter geotherms; the insights that metamorphic–magmatic timescales provide into evolving tectonic styles and thermal regimes and ultimately, the stabilization of felsic crust and cratons. We welcome contributions from researchers at all career stages and across diverse fields, including metamorphic and igneous petrology, isotope and trace element geochemistry, diffusion kinetics, geochronology, and geodynamic modelling. The session aims to foster interdisciplinary dialogue on the processes and tempos that shaped Earth’s early evolution.

The record of Large Igneous Provinces (LIPs) is continually expanding back in time and now includes events back to 3.8 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 utilizing 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.

Intraplate volcanism provides a unique window into the structure, composition, and dynamics of Earth’s mantle. While mantle plumes have long been invoked to explain such volcanism, accumulating geochemical, geophysical, and experimental evidence highlights the critical role of the mantle lithosphere in controlling melting processes, magma compositions, and eruption dynamics. This session aims to bring together researchers investigating the generation, transport, and evolution of mantle melts, with a focus on their role as both chemical agents and dynamic components of Earth’s interior, and the balance between lithospheric and asthenospheric contributions to oceanic and continental intraplate volcanism.

The Earth’s mantle has a limited number of mechanisms that produce melt. Temperature anomalies, pressure drops, and the addition of volatile components (such as CO₂ and H₂O) remain the primary drivers of melting. Once generated, melts may either remain at depth, ascend toward the surface to erupt, or stall during their upward migration, depending on their chemical composition. Interconnected melts can drastically affect the rheological and electrical properties of the surrounding rock. Furthermore, migrating melts provide the fastest means of transporting chemical elements across kilometer-scale distances within the Earth’s mantle and crust. These melts also interact with their host rocks, driving metasomatic processes within the lithospheric mantle.

Although significant progress has been made through natural observations, laboratory experiments, and numerical simulations, much work remains to be done to better constrain the nature and properties of melts and to relate these characteristics to transport properties across various scales. Melts are particularly understudied in regions with complex compositional heterogeneity. This session aims to showcase recent research on melt genesis, distribution, composition, melt-rock reactions, and migration in deep Earth materials, drawing from experimental investigations, studies of natural samples, and numerical simulations. Contributions involving machine learning approaches and results from large melt-related databases are also welcome.

Recent analytical and methodological developments have enabled geoscientists to study the complex mineral cargo of magmatic rocks—including major, accessory, and xenocrystic minerals and their inclusions—with unprecedented detail. This has significantly enhanced our understanding of magmatic systems over a broad range of spatial, temporal and compositional scales on Earth and also on other planets and solar system materials. Despite these advances, there are still several aspects that are still not fully understood for example: constraining the timing and tempo of magma emplacement and eruption; clarifying the link between plutonic and volcanic rocks; resolving the interaction between magmas and host rocks; elucidating the evolution of volatiles in the plumbing system and their release into the atmosphere and oceans; exploring the formation of ore systems including copper porphyry and pegmatite-style deposits; for our solar system, a mineral perspective is needed to help understand the differentiation of rocky bodies as well as the general distribution of water and other volatiles.

In this session, we invite contributions aiming to improve our understanding of the origin, emplacement, and environmental impact of mafic to felsic magmatic systems using a mineral-based approach that integrates multiple disciplines such as geochronology, petrochronology, textural, geochemical and isotopic analyses, as well as the study of melt, fluid, and solid inclusions. We welcome studies on classic minerals such as clinopyroxene and zircon, but we particularly encourage contributions on minerals that have been subject of recent developments, for example apatite and baddeleyite.

Volcanic eruptions profoundly impact communities worldwide, with arc volcanoes posing some of the greatest hazards. By focusing on subduction-zone magmatic systems, this session aims to advance our understanding of magma genesis, chemical evolution, storage conditions, eruption primers, triggers and associated timescales — ultimately probing the architecture and dynamics of these systems. We welcome contributions that investigate eruptive products across scales, from microanalytical and geochemical observations (e.g., melt inclusions, crystal zoning, isotopes, volatiles), to field studies and experimental approaches. Interdisciplinary perspectives are strongly encouraged, including work that integrates geochemistry with geophysics, physical volcanology, and numerical or analytical modeling, as well as studies that link petrological observations to volcanic unrest. By connecting micro-scale geochemical and textural signatures to broader volcanic processes and behavior, this session seeks to bridge observations of volcanic products with large-scale hazard implications. In doing so, we highlight the value of combining diverse methods to better understand volcanic unrest and improve hazard assessment.

Magmatic systems provide key insights into the origin and evolution of the Earth and other planets. Magmas sample diverse mantle sources and undergo complex physical and chemical processing during their ascent to shallow reservoirs prior to cooling or eruption. These processes, and the time scales over which they occur, govern the transfer of mass, heat, and volatiles through the planet. They encompass partial melting in the upper mantle, magma storage, differentiation, crystallization, and ascent dynamics across diverse tectonic settings. Processes on the micro-scale (e.g. speciation, partitioning or diffusion between melts, fluids, and crystals) influence macro-scale processes such as crustal evolution, eruption style and associated hazards. Understanding these multiscale, multiphase, and multirate processes—and their roles in planetary evolution—often requires an integrated approach combining observations, experiments, and computational methods.

This session aims to showcase the broad impact of data-driven, computational approaches to the study of magmatic systems and provide a platform for technical exchange, bringing together researchers working on statistical data analysis, thermodynamics, forward and inverse modelling, machine learning, and other computational methods, as well as advances in analytical techniques that provide the data these models require. Topics of interest include:

• Mantle and crustal evolution;
• Processes and rates of magma generation, differentiation, transport, and storage;
• Eruption dynamics and hazards.

We encourage contributions that explore the theory, application, and validation of computational approaches in the context of experimental and observational data both from Earth and other planetary bodies. We further welcome multidisciplinary approaches that integrate petrological, geochemical and geophysical observations.

Hydrothermal systems are among the most dynamic and fascinating environments on Earth, where fluids interact with the subsurface to shape geological, chemical, and mineralogical evolution. This session welcomes contributions from scientists at all career stages working across the broad spectrum of hydrothermal geochemistry. We invite studies on the quantification and modeling of aqueous speciation in hydrothermal fluids, inorganic and organic hydrothermal chemistry, molecular- and atomic-scale modeling of fluid properties, isotope geochemistry, mineral-fluid interactions, and applications to natural geothermal and ore-forming systems. Contributions that bridge experimental, theoretical, and field-based approaches are particularly encouraged. The goal of this session is to foster discussion and collaboration across disciplines to advance our understanding of the chemical and physical processes governing hydrothermal systems - from fundamental molecular mechanisms to their large-scale geological and economic significance.

Volatile elements influence many processes throughout the upper mantle and lithosphere, including partial melting, magma genesis and evolution, eruption dynamics, redox changes, hydrothermal cycling, metal mobilisation, crustal recycling, and mineralogical transformations. Moreover, their escape through volcanoes and active seismic regions provides a unique window into the planet's dynamics. The compositions (including stable isotope ratios) of volatiles such as H, B, Li, S, halogens, and noble gases are powerful tracers, offering insights into processes within volcanic plumbing systems and active fault zones, and the broader chemical and isotopic evolution of Earth's interior.

By combining volatile compositions with petrological, geochemical, and geophysical observations, this session explores how volatiles influence dynamic processes in the Earth's interior. The release of these volatiles is the driving force for volcanic eruptions, has fundamentally shaped the composition of Earth’s atmosphere, and plays a central role in the formation of magmatic ore deposits and earthquake nucleation. Constraining the source, abundance, and behaviour of volatiles in magmas thus has far-reaching and cross-disciplinary applications, including the use of volcanic gases as a tool for volcano monitoring and eruption forecasting, determining the effects of past and future eruptions on Earth’s atmosphere and climate, and understanding the formation of economically important mineral deposits. We invite submissions from a broad range of disciplines that aim to constrain the behaviour of volatiles from source to surface. We also welcome contributions that utilise volatiles and their stable isotope compositions to explore the role of melts, fluids, and volatiles in volcano-magmatic systems and active fault zones.

Mining activities, particularly in the coal, metal, and rare earth sectors, are major contributors to environmental degradation, producing dust, greenhouse gases, acid mine drainage, and significant water contamination. These impacts extend beyond mine sites, posing risks to ecosystems and human health that are increasingly intensified by climate variability. Rising temperatures, altered rainfall patterns, and extreme weather events reshape hydrogeological regimes, mobilize pollutants, and exacerbate the vulnerability of soil and water resources.

This session invites contributions that adopt a multiscale analytical lens, linking site-specific geochemical and hydrogeological studies to regional and global assessments of mining-related emissions and contamination under changing climatic conditions. We seek interdisciplinary work spanning geochemistry, hydrogeology, climate science, environmental engineering, and policy.

We welcome studies on:

• Geochemical and isotopic tracing of contaminants from mining areas

• Acid mine drainage processes, impacts, and mitigation

• Hydrogeological modeling of contaminant transport under climate stress

• Remote sensing and GIS-based assessments of mining impacts

• Greenhouse gas emissions from tailings and overburden

• Temporal water quality trends in mining regions

• Nature-based and climate-adaptive strategies for pollution control

• Policy and regulatory frameworks for sustainable mining

By integrating micro- to macro-scale perspectives, this session aims to advance both scientific understanding and actionable approaches to mitigate the environmental footprint of mining in a changing climate.

Lithium is a key metal in the global energy transition, sourced from diverse geological systems including pegmatites, granites, clays, continental brines, and oilfield brines. These deposits represent significant geochemical anomalies in the Earth’s crust and hydrosphere, often linked to specific tectonic, magmatic, and climatic settings. Understanding how lithium is enriched, transported, and concentrated across the Earth systems is crucial for guiding exploration and promoting sustainable development.

This session explores lithium enrichment across magmatic-hydrothermal, volcano-sedimentary, and brine systems, with emphasis on geodynamic controls, crustal recycling, and fluid–rock interactions. We welcome interdisciplinary contributions on lithium geochemistry, mineralization, and cycling across Earth’s spheres. Submissions linking lithium resources to tectonic evolution or paleoclimate transitions are particularly encouraged. We also invite research on geometallurgy, innovative extraction technologies, and sustainable strategies. The session aims to serve as a platform for collaboration across geochemistry, mineralogy, petrology, economic geology, and environmental science, advancing deeper understanding and the responsible development of this critical resource.

Orogenic Au deposits, a major source of Au for our society, formed throughout the history of our planet in convergent settings. The class has an important variability in terms of mineralization style, mineralogy, and alteration signatures. Efficient exploration of orogenic Au deposits requires a next generation of ore deposit model, in which key timing, structural, lithological, and physicochemical parameters leading to auriferous fluid generation, Au precipitation and accumulation in the continental crust are well constrained. In addition, successful exploration involves maximizing the information locked in the alteration halo of mineralized zones to create new vectoring tools.

We welcome contributions on orogenic Au deposits from the development of new exploration methods/concepts to studies focusing on Au precipitation/remobilization mechanisms at mineral scales.

Carbonatites and alkaline/peralkaline igneous rocks represent rare but key manifestations of mantle and crustal processes typically associated with intracratonic anorogenic and postcollisional settings. Their occurrence provides crucial insights into mantle/crustal source heterogeneity, the role of volatiles in magma and deposit genesis, and the links between lithospheric architecture and magmatic activity. Beyond their petrological significance, these systems are also of considerable economic importance, as they host world-class deposits of critical raw materials, such as rare earth elements, niobium, phosphorus, zirconium, and fluorine. Understanding the genesis, evolution, emplacement, and metallogeny of carbonatites and alkaline/peralkaline igneous rocks therefore has implications that extend from mantle geodynamics to resource sustainability.

This session invites contributions that explore the wide spectrum of research related to carbonatite and alkaline/peralkaline magmatism and their implication for the formation of mineral deposits. We welcome studies on mantle and crustal sources, formation processes, and the role of fluids and metasomatism in generating a wide variety of rock units and deposits. Contributions focusing on field relationships, mineralogy, geochronology, isotope and trace element geochemistry, experimental petrology, and numerical modelling are encouraged, as well as studies highlighting ore-forming processes and the distribution of critical metals. By bringing together diverse lines of evidence, this session aims to stimulate discussion on the petrogenesis, evolution, alteration, and economic potential of these unique and diverse magmatic systems.

Marine mineral resources have the potential to play an important role in securing the future supply of base and critical metals required for the energy transition and the expansion of e-mobility. Many of these resources are concentrated in deposits on or beneath the present-day seafloor and host a wide spectrum of commodities, including polymetallic massive sulphides and metalliferous sediments, polymetallic nodules, Co-rich Fe crusts, and REE-bearing phosphorites. In light of increasing metal demand, supply risks, and geopolitical challenges, substantial research efforts have been directed towards understanding both, the economic potential of these deposits and their role in the abyssal ecosystems.

At the same time, exploration and the prospect of mining such deposits raise complex technical, environmental, societal, and regulatory issues. This session therefore welcomes contributions on all aspects of marine mineral deposits, including but not limited to: (1) deposit formation, characterisation, and mineralogy; (2) biogeochemical interactions among oceanic crust, hydrothermal systems, sediments and seawater; (3) habitat characterisation, ecosystem functioning, and connectivity; (4) environmental consequences of resource exploitation activities; (5) innovations and application of exploration technologies; (6) innovations in monitoring and management of mining activities; and (7) associated legal, societal, ethical, political, and economic dimensions.

We particularly encourage submissions that foster a balanced and critical discussion on the economic relevance and environmental impacts of deep-sea mining, and the scientific progress in the study of marine mineral deposits and associated ecosystems.

This session, held in honor of the pioneering legacy of Professor Dietrich Welte,  will showcase the latest breakthroughs in hydrocarbon geochemistry across the geologically diverse and economically vital basins worldwide. From mature basins to the frontier deep-water settings, new geochemical tools are revolutionizing our understanding of hydrocarbon generation, migration, and accumulation. A particular focus will be on the role of Earth sphere interactions in shaping hydrocarbon systems, especially in the context of ultra-deep hydrocarbon exploration that targets reservoirs influenced by deep crustal and mantle processes.

We seek contributions that employ state-of-the-art geochemical proxies to de-risk exploration, optimize resource development, and enhance our fundamental knowledge of sedimentary systems and their connections to deeper Earth processes. The session aims to foster interdisciplinary dialogue, linking advanced geochemistry with geology, geophysics, and deep Earth science to build more predictive subsurface models for energy resources.

Key topics of interest include, but are not limited to:

Advanced Organic Geochemistry: utilizing biomarkers and isotopes for oil-source correlation and reservoir studies; Innovative Isotope Geochemistry: (H, C, clumped, metal) to decode charge history and fluid-rock interactions; Geochemistry for Unconventional Resources: characterizing in-situ systems and expulsion efficiency; Earth Sphere Interactions & Ultra-Deep Exploration: focusing on hydrocarbons influenced by deep crustal/mantle processes; Global Integrated Case Studies: merging geochemistry with geophysics to solve exploration challenges.

Nuclear waste repositories contain packages of engineered waste such as glass, ceramics, geopolymers and spent nuclear fuel that may generate significant heat from initial thermal loading and ongoing radioactive decay. This will be further complicated as new fuel types are employed for Gen IV reactors. The performance of stored materials as well as the barrier system surrounding the canisters containing these materials must be well understood over geological time scales to ensure their safe isolation. If water intrusion occurs there is the potential for hydrothermal and radiolysis driven alteration of the canister materials, mineral transformations within the barrier components and finally alteration of the waste forms themselves. In turn, temperature-driven changes can influence the release, sorption, and transport of radionuclides from the waste canisters and waste forms through the barrier and into the surrounding geological environments. Understanding all these processes is essential, as they directly affect the long-term stability and containment performance of a deep geological repository. This session invites contributions on recent advances addressing these problems, including, but not limited to, case studies and experiments on solid alteration and radionuclide behavior under repository-relevant thermal and geochemical conditions, as well as predictive performance modeling toward a better understanding of the factors ensuring the safe isolation of nuclear waste over geologic timescales.

Sedimentary basins are increasingly recognized as important hosts for critical minerals essential to the global energy transition. These deposits record complex basin evolution, stratigraphic architecture, diagenetic processes, fluid–rock interactions, and, in some cases, the influence of underlying basement rocks that control the distribution and concentration of critical minerals within sedimentary successions. Therefore, understanding these coupled processes are essential for predicting where critical minerals occur, getting insight on critical mineral systems, how they evolve, and how they can be sustainably explored.

This session invites contributions that examine the geological, geochemical, and hydrogeological controls on sedimentary-hosted critical mineral systems across diverse settings, from brine-bearing strata in sedimentary basins, sedimentary and metasedimentary deposits. We particularly welcome studies integrating basin evolution, stratigraphy, sedimentology, petrography, diagenesis and fluid–rock interaction processes, using outcrop, core, and subsurface datasets, as well as advances in isotope geochemistry, mineral mapping, hydrothermal or basin modeling. Case studies employing novel analytical or computational methods (e.g., in-situ trace-element analysis, hyperspectral imaging, or automated and/or machine-learning-based mineral detection) are encouraged. The session aims to foster interdisciplinary collaboration in sedimentology, geochemistry, basin analysis, and basement rock to advance understanding of sedimentary-hosted critical mineral systems.

Global development and the energy transition are fundamentally tied to the availability of critical and strategic metals such as copper, cobalt, nickel, and rare earth elements. Non-traditional resources have the potential to play an important role in meeting the significant and growing demand for critical minerals. Non-traditional resources include industrial waste streams from existing mines and organic-rich sedimentary rocks such as black shale, coal, lignite, and oil shale. This session aims to illuminate pathways and catalyze interdisciplinary dialogue toward a more sustainable and resource-efficient future through the presentation and discussion of field, laboratory, and/or modeling studies of critical mineral production from non-traditional resources.

Subsurface fluids are crucial for element mobilization and fractionation in the Earth’s crust and drive rock metasomatism and ore-forming processes in many geological systems. These fluids circulate and interact with rocks over a wide temperature and pressure range, leading to a significant diversity in physical and chemical properties that need to be understood across scales. Ore-forming fluids can span an enormous range of compositions, from relatively dilute aqueous solutions through to complex solutions and to an array of melts (e.g. carbonate, sulfide, sulfate and/or halide). This session aims to showcase the diversity of ore-forming fluids and fluid-driven processes across various mineral deposits, from well-known systems with emerging insights to novel and enigmatic deposits where our understanding is still evolving.

We welcome new developments in geochemical modeling, phase equilibria modeling, thermodynamic databases, in situ spectroscopy, trace elements, isotopic work, and geochemical analysis of natural minerals across scales to understand element behavior in crustal fluids and mineral deposits. We invite contributions that quantify geochemical processes across relevant P–T–X ranges, emphasizing robust thermodynamic and activity-coefficient treatments, experimental constraints on solubility, complex stability, and partitioning, and first-principles modeling that resolves hydration structures, complexation, redox energetics, surface complexation, adsorption, and nucleation pathways.  

The growing demand for mined resources poses major challenges for environmental management and the sustainability of mineral supply chains. Mine wastes (e.g., waste rock, tailings) can be both an environmental liability as well as a potential secondary resource for critical minerals. Effective strategies for remediation and reprocessing are needed, but these require an integrated, quantitative understanding of the processes that control contaminant mobility and the recovery potential of valuable elements. 
This session invites contributions that advance our understanding of the geochemical, mineralogical, hydrogeological and/or microbiological processes governing the environmental risks or revalorization opportunities associated with mine wastes. We particularly welcome studies that bridge fundamental molecular-scale geochemistry with practical field-scale approaches to remediation or (re-)extraction. 
Submissions may feature:
1. Site investigation and risk assessments of complex, acidic to alkaline environmental or engineered systems; 
2. Laboratory experimentation or field studies into reprocessing routes, environmental remediation or both, including treatment technologies with (coupled) dissolution-reprecipitation for recovery or stabilization; 
3. Cutting-edge analytical techniques, including automated mineralogy, metal(oid) speciation, (non-traditional) isotope systems, synchrotron-based tools, or geomicrobiology and metagenomics; 
4.      innovative thermodynamic and reactive-transport modeling methods or material life-cycle analysis approaches. 

Of interest are globally relevant contaminants like redox-sensitive metal(oid)s and radionuclides in mining settings, as well as the occurrence and recovery potentials of technology-critical elements (e.g., Cu, Co, Ni, Zn, Li, or rare earths). By linking fundamental (bio)geochemistry to applied contexts in resource recovery and environmental protection, this session explores new pathways to sustainable mine waste management and responsible sourcing of materials.

To meet society’s goal to keep temperature rise below 2°C, it is clear that we urgently need to reduce greenhouse gas emissions and to actively remove CO₂ from the atmosphere. The last decade has seen a surge in engineered and nature-based solution pathways for carbon dioxide removal (CDR), including mineral and biological-based technologies. Among them, carbon mineralization (MC), which has the highest CO₂ storage potential from mafic and ultramafic rocks and from alkaline by-products, is the safest way to sequester CO₂ as evidenced by natural occurrences, onshore and offshore, and mine tailings. The use of industrial waste by-products can also help to promote global circular carbon economies and sustainable practices. However, there are still limitations in our understanding of reaction pathways and efficiency such as the mechanisms controlling slow kinetics for MC, the formation of passivation layers, the impact of hydrodynamics, T, P and fluid composition. As such, the conversion of CO₂ into carbonates is still under study and development at various scales. In this session, we encourage contributions of innovative research from laboratory experiments, field-studies, and theoretical models on carbon (bio)mineralization, serpentinization as well as the use of mineral residues and/or industrial waste by-products for CO₂ sequestration.

Critical metals such as Co, Ni, Cu, Mo, Sn, W, U are essential for modern industry and underpin the global transition to low-carbon technologies. These metals are concentrated in ore systems through a continuum of magmatic to hydrothermal processes, which control their sourcing, transport, fractionation and enrichment from the mantle to the upper crust. This session welcomes contributions that explore the latest advances in understanding magmatic–hydrothermal ore systems, addressing ongoing uncertainties related to melt and fluid evolution, metal solubility and speciation, ore-related volatile and sulfur behavior, and processes controlling metal enrichment. By bringing together perspectives from different magmatic(-hydrothermal) systems, such as orthomagmatic Ni–Cu–Co-=PGE, porphyry Cu–Au–Mo systems, iron-oxide-apatite, IOCG, and granite-related Sn-W and U systems, this session aims to further advance understanding of magmatic-hydrothermal ore-forming processes across multiple tectonic settings and crustal levels, establish robust mineralogical and geochemical fertility indicators, and stimulate innovative strategies to enhance exploration of these metal resources. We encourage submissions employing petrography, mineral chemistry, melt and fluid inclusions, experimental studies, computational approaches, and integrated exploration methods and strategies. By emphasizing the fundamental processes driving metal enrichment, the session aims to highlight the principles governing ore fertility and guiding discovery.

Fluid-rock interactions govern the chemical and physical evolution of the subsurface and are central to understanding processes such as element transport. Understanding and predicting the coupled processes of fluid flow, chemical reactions, and reactive transport is essential for addressing key challenges in geosciences, including geological storage of nuclear waste, carbon sequestration, contaminant transport. These processes also underpin advancements for the energy transition, such as hydrogen exploration, geothermal energy development, uranium in situ recovery, and mitigating environmental impacts like acid mine drainage.

Ulrich Mayer has been a leader in developing multicomponent reactive transport models that couple chemical reactions, multiphase flow, and microbial processes across scales. His work has provided a quantitative framework for investigating how fluid-rock systems respond to chemical gradients in both natural and engineered environments, with applications in areas such as gas migration, mineral dissolution/precipitation, porosity-permeability evolution, and radionuclide behavior.

This session invites contributions highlighting recent advancements in (i) groundwater biogeochemistry and biogeochemical modeling, (ii) theoretical, computational, and experimental studies of coupled hydrogeological processes, (iii) innovative upscaling techniques linking pore-scale to field-scale behavior, (iv) advanced imaging tools for porous media characterization, and (v) AI-based tools to accelerate experimental analysis and geochemical modeling. Particular emphasis will be placed on integrative studies, uncertainty quantification, and case studies from field and laboratory experiments that validate or challenge existing models.

Description: Hydrogen (H₂), helium (He), and other noble gases are emerging as critical resources in the global transition to a low-carbon economy. This session provides a comprehensive forum to explore their full lifecycle, from generation to migration, accumulation, and sustainable utilization. We welcome interdisciplinary contributions that integrate geochemical, geological, geophysical, and microbiological perspectives. Topics of interest include, but are not limited to: 1) Origins and sinks: abiotic and biotic processes, such as serpentinization, radiolysis, and microbial activity, that generate or consume these gases; 2) Gas dynamics: physical and chemical controls on migration, accumulation, and the integrity of geological seals; 3) Resource systems: studies of natural hydrogen seeps, helium-rich reservoirs, and gas-bearing ultramafic systems, and their interplay with conventional hydrocarbons; 4) Innovative methods: quantitative assessments using field, experimental, and modeling studies. We particularly encourage submissions on AI-driven exploration, advanced drilling/sampling, and novel geophysical techniques for detection and sustainable extraction, and 5) Planetary perspectives: comparative studies linking Earth system science with planetary exploration to understand gas behavior across the solar system. By fostering collaboration among geoscientists, planetary researchers, and energy strategists, this session aims to advance fundamental science and develop sustainable strategies for exploring and utilizing these vital resources.

Geothermal energy offers one of the few clean and reliable sources of scalable baseload power. However, the geochemistry of reservoir fluids, and how to manage their potentially harsh nature, including in volcanic and other natural hazard settings, requires continued research to unlock their full potential. Advancing geothermal technologies requires a thorough understanding of reservoir fluid geochemistry at a range of temperatures, pressures, bedrock types, salinity, residence time, microbial activity, initial fluid composition, and dissolved gases through space and time. Novel geochemical and mapping methods have thus been developed over several decades, and there has recently been a boom in numerical and virtual data management tools such as artificial intelligence (AI), machine learning, and multivariable analysis. We solicit contributions on recent advancements in the methodology, analysis, and geochemical monitoring in active geothermal and related dynamic systems to better understand the geochemistry of geothermal reservoir fluids – including those at high enthalpies. This includes the use of geochemical pathfinders for exploration and resource management. Contributions focused on geothermal activity related to critical mineral exploration, volcanism, and moving aquifers are also welcome.

This session is dedicated to microbeam instrumentation and new methods (e.g. electron probe microanalysis, secondary ion mass spectrometry, laser ablation-inductively coupled plasma-mass spectrometry, laser-induced breakdown spectroscopy, etc.), and reference materials used for the development, calibration, and interpretation of stable/radiogenic isotopic and/or elemental measurements in geochronology, thermochronology, igneous and metamorphic petrology, detrital mineral provenance, critical mineral systems, geobiology, 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 minerals in the solid state such as LA-TOF-ICP-MS elemental and isotopic mapping of geo-and-biological materials or LA-(MC)-ICP-MS/MS analyses for geochronology of beta-decay isotope systems or avoiding and/or eliminating isobaric interferences. Reference materials may include natural or synthetic mineral, glass or pressed powder solids. 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. The interdisciplinary nature of this session is meant to stimulate cross pollination of methodologies and application spaces.

Biogeochemical models of water columns, sediments, groundwater, soils, and laboratory systems have become valuable tools for understanding chemical, physical, and biological interactions that shape the environmental conditions on both local and global scales, in both modern systems and over geological time. Modeling applications continually evolve, and challenges arise in developing new types of models, including investigations of Early Earth and Mars, simulating adaptations and evolutions of microbial communities, and reliably applying models across systems. We invite contributions that report on modeling applications, new approaches to describing coupled biogeochemical and physical dynamics, improved descriptions of biological activities, particularly those that link geochemical descriptions to multi-omics data, or new computational approaches including machine learning. We also welcome submissions that address challenges in the interpretations of model results, including the issues of predictability, reproducibility, course-graining, and sensitivity analysis.

Quantitative predictions of petrological systems, commonly pressure-temperature conditions, are key to understanding solid Earth processes, including fluid-rock interaction, melt generation and extraction, mineral resource formation, and the tectonometamorphic evolution of geological terrains. Linking petrological processes across scales increasingly relies on accurate, process-based modelling. Recent advances—including high-resolution compositional mapping, optimisation of thermodynamic datasets, statistical inversion techniques, and coupling of phase equilibria and thermomechanical models—are expanding the scope and precision of petrological analysis. Large natural datasets and comparative studies across diverse lithologies provide robust tests of model performance and strengthen the empirical basis for interpretation. At the same time, emerging machine-learning and AI approaches are beginning to reveal new patterns in these datasets and automate complex workflows.

This session highlights the future of quantitative petrology. We invite contributions that demonstrate innovations or novel applications of phase-equilibrium modelling and thermobarometry, data-driven or automated approaches, and integrated modelling across petrological, geochemical, and thermomechanical domains that will yield new insights into geological processes. We also welcome studies focused on open tools, workflows, and community resources that support and accelerate quantitative research for petrologists. Submissions from researchers at all career stages, including PhD students, are warmly encouraged.

Identifying the sources of metals and other earth-derived materials used in the production of archaeologically recovered artifacts lies at the core of archaeometry. This session explores how advances in analytical, isotopic and geochemical techniques are reshaping our ability to reconstruct ancient technologies, trade networks, and human-environmental interactions. We invite contributions that highlight the intersection of geochemical innovation and archaeological inquiry—ranging from isotopic and geochemical fingerprinting of ores and metallic artifacts to provenance studies of ceramics, pigments, and lithic materials. We especially welcome interdisciplinary work that bridges laboratory and field perspectives, develops new reference materials, or applies geochemical tracers to questions of technology, human behavior, and environmental change in the past.

This session explores recent developments in methods and tools for advancing thermodynamic modelling of geochemical processes. These advances include both improvements to computational approaches, based on Gibbs Energy minimisations, as well as new developments using machine learning (ML)-based techniques.

Computational thermodynamic software tools (e.g., MELTS, THERMOCALC) rely on existing databases and thermodynamically-derived solution models. Recent improvements (e.g., ENKI, GEMS, ThermoHub, MAGEMin, Reaktoro, Cantera, etc.) have been developed to broaden the range of geological and planetary settings in which existing thermodynamic models can be applied, and to assist in developing new thermodynamic models.

Concurrently, ML techniques are increasingly applied to accelerate the prediction of mineral stability and chemistry, evolution of liquid compositions of major oxides, aqueous speciation, mineral thermobarometers, and reaction kinetics, and to fill gaps in thermodynamic properties and model parameters.

This session invites contributions that demonstrate how novel computational approaches (e.g., Bayesian methods, speciation, or expanded compositional systems), including both traditional and machine-learning approaches, can advance the creation and application of thermodynamic models. Application of such models might include magmatic systems, crustal evolution, shallow and deep magmatic brines and other fluids, and non-terrestrial planet compositions.

The physics and chemistry of geochemical systems define a rapidly evolving frontier in Earth and environmental sciences. This session brings together experimental, computational, and data-driven perspectives to unravel the mechanisms that govern geochemical reactions, mineral transformations, and interfacial dynamics across multiple spatial and temporal scales. From amorphous precursors to crystalline minerals, and from nanoscale interfacial reactions to field-scale geochemical processes, we aim to advance an integrated understanding of how complex mineral–fluid systems evolve. Topics of interest include, but are not limited to:
(1) Mineral-water, organic-mineral interactions, and biomineralization, (2) Amorphous and metastable intermediates and nonclassical crystallization, (3) Mineral dissolution and weathering, (4) Geochemistry of critical elements, connecting nanoscale to macroscopic rates, (5) Coupled experimental–computational–AI workflows for predicting mineral reactivity under subsurface environments. By integrating cutting-edge experimental methods, advanced modeling, and AI-enabled approaches, this session aims to illuminate the multiscale dynamics that govern geochemical transformations, enabling predictive understanding of mineral evolution in various systems, including weathering, hydrothermal alteration, carbon storage, and engineered subsurface environments.

This session invites contributions that highlight the knowledge-generating potential of data science and numerical methods in geochemistry. We welcome submissions that apply or develop quantitative tools to address geochemical questions across scales from nano- to macro- scales. Relevant approaches include (but are not limited to) quantum mechanics, molecular dynamics, chemical kinetics, isotope effects, biogeochemical modeling, hydrodynamics, geodynamics, and planetary dynamics.

Methods in statistical learning, machine learning, artificial intelligence, and other numerical methods are increasingly capable of addressing scientific questions that arise in field, laboratory, and simulation work. In many cases, combining experimental and computational approaches is essential to bridge the gap between laboratory setups and natural systems. All works displaying a chosen method in numerical methods or data science as a central tool in generating knowledge are welcome.

This session aims to bring together geochemists at all career stages to present and discuss recent advances and innovations, including improvements or new quantum chemistry methods, big data or machine learning techniques applied, novel laboratory and analytical approaches.

Development of high-precision measurement of isotope ratios has provided novel and valuable tracers and chronometers to investigate sources and processes across the natural sciences. Mass spectrometers are now capable of measuring the whole periodic table from long standing noble gas isotope-based chronometers to non-traditional stable metal isotope applications. Furthermore, the drive to improve isotope ratio measurements shows no signs of slowing down. Methodological developments – including those in the realms of sample preparation and introduction, chromatographic separation and new reference materials – decrease sample size, increase sample throughput and analytical reproducibility, ease of use and inter- and intra-lab quality control. Technical developments in mass spectrometry related to ion sources, collision cells, and mass prefilters on multi-collector instrumentation, are also critical to advancing the application of isotopic tools. All branches of isotope ratio mass spectrometry have benefitted from developments in collector technology with high-ohmic current amplifiers, charge-collection current amplifiers and multiple electron-multiplier detectors extending detection capabilities, while improving both analytical precision and accuracy. This session aims to bring together isotope geochemists to discuss recent advances and innovations in the field. We invite contributions on novel approaches to the collection of isotopic data, including new sample preparation and introduction techniques, innovative technology, instrument design as well as new data reduction strategies. We encourage contributions from early career researchers and those from traditionally underrepresented groups, the submissions of null or unexpected results that enhance understanding of the field are also welcome as are contributions that showcase ‘works in progress’.

Emerging methods in environmental (bio-)geochemistry are reshaping our understanding of contaminant dynamics, mineral reactions, and remediation processes in complex natural and engineered systems. This session aims to highlight cutting-edge developments in both experimental and computational (bio-)geochemistry that support sustainable resource management and environmental protection. We invite contributions that integrate novel experimental observations, reactive transport modelling, and applied remediation strategies to elucidate the coupled hydrogeological, geochemical, and biological processes controlling contaminant fate and mineral evolution in natural, mining and other engineered environments.

We invite studies in the following areas:

1. Operando and in-situ geochemical techniques — including synchrotron-based X-ray absorption spectroscopy (EXAFS/XANES), Raman/IR/XPS spectroscopy, microfluidic or flow-through reactors, and redox-variable cells — designed to understand mineral dissolution and precipitation dynamics, and mineral transformations under variable conditions.
2. Reactive transport modelling — integrating field data, laboratory kinetics, mineralogical and petrological characterization, and thermodynamic databases to simulate and predict contaminant mobility, metal attenuation, and water quality evolution in mining and natural environments.
3. Applied case studies and remediation innovations — addressing challenges in mine drainage, contaminant cycling (e.g., Fe, Mn, As), and waste reprocessing, including the coupling of experimental insights with modelling frameworks to support long-term predictions, mine closure strategies, and net-zero transitions.

By fostering dialogue among geochemists, hydrogeologists, environmental engineers, and modellers, this session seeks to advance a holistic understanding of reactive processes across scales — from the molecular to the field — and to promote integrative approaches that drive innovation in environmental (bio-)geochemistry, sustainable mining, and environmental remediation.

Earth’s stratigraphic archive across pre-, syn-, and post-glacial intervals provides critical insights into the causes, extent, and consequences of global-scale glaciations, as well as their impact on biogeochemical cycles. This session will explore major glaciations from the Paleoproterozoic through the Neoproterozoic, with a focus on models outlining the possible causes of Earth’s most extreme ice ages and their influences on surface environments throughout the Precambrian. We also encourage studies on the consequences of these glaciations, from the stratigraphic and geochemical signatures of glacial deposits to their potential impacts on evolution, including the proliferation of eukaryotes following the Cryogenian snowball glaciations and Ediacara fauna after the Gaskiers glaciation. We invite contributions that encompass sedimentology, stratigraphy, geochemistry, geochronology, paleobiology and numerical modeling to encourage interdisciplinary discussion of Earth’s most profound climate transitions and their impacts on the biosphere.

Microbialites represent some of the most compelling archives for Earth and life co-evolution through time. Resulting from the interaction of microbial communities with their environment, they have recorded the major geological, biological, climatic, and geochemical trends and events that have shaped the Earth’s surface over billions of years. The diversity of microbialite morphology, geochemistry, microbiology, and depositional contexts, from the Archean to the present day, highlights their remarkable adaptability and ability to record biogeochemical cycles, ecosystem patterns, and environmental changes.

Integrating insights from geochemistry, mineralogy, sedimentology, micro-/geobiology, and astrobiology, this session aims to explore how microbialites both record and mediate evolutionary and environmental processes throughout Earth’s history, whether at a local or global scale. We invite contributions exploring all facets of microbialites – from their role in paleoenvironmental reconstruction to their responses to global changes, such as oxygenation events, mass extinctions, and climatic fluctuations – and we support interdisciplinary studies. We also welcome investigations into the significance and functioning of modern microbialites, especially in relation to the geological record. Furthermore, we strongly encourage studies that apply innovative approaches to microbialite research, thus helping to modernize and broaden the field. This includes the use of new geochemical proxies, as well as experimental and numerical simulations, machine learning, and AI tools, to shed light on the formation, preservation, and interpretation of microbialites.

This session aims to host a contest of ideas and seeks to advance our understanding of how ocean-atmosphere redox evolved across the Great Oxidation Event (GOE). The GOE represents a pivotal transformation in Earth history, marking the sustained rise of atmospheric oxygen and a fundamental reorganization of ocean chemistry. Understanding redox dynamics across this transition is essential to reconstruct the coupled evolution of atmosphere-biosphere, and elemental cycles in deep time. This session invites contributions that investigate ocean redox history before, during, and after the GOE, emphasizing the integration of geochemical, sedimentological, and numerical modelling approaches. We encourage both bulk rock and in-situ studies employing redox-sensitive trace element enrichment factors (including Mo, V, U, Re), stable isotope systems (e.g., δ⁹⁸Mo, δ¹⁸⁶W, δ⁵⁶Fe, δ³⁴S, Δ³³S, δ¹³C, δ¹⁵N), iron speciation techniques (Fe_py/Fe_HR, Fe_HR/Fe_total), and novel or emerging proxies developed for redox reconstruction. Equally welcome are studies coupling these records with sedimentological archives, advanced numerical models and machine learning applications on large geochemical datasets, offering new ways to unravel complex cause–effect relationships. We also strongly encourage submissions that challenge the general consensus on our current understanding of the GOE. We aim to facilitate an open discussion on both mainstream and unconventional research findings by integrating traditional and emerging redox proxies, sedimentological evidences, and state-of-the-art modelling frameworks. We aim to bring together studies that assess the nature of GOE (step wise or sharp rise in oxygen), the triggers and feedbacks sustaining oxygenation, and the broader consequences for nutrient cycling, climate regulation, and the biosphere.

Please join us as we explore how microbial life has shaped—and been shaped by—Earth’s evolving chemical and physical landscape. This session will focus on uncovering the dynamic feedbacks among microbial metabolism, mineral interactions, and environmental chemistry that have influenced the oceans, atmosphere, and crust throughout Earth’s history. While signals of microbial life include molecular, elemental, and isotopic biosignatures, it is essential to anchor these proxies in modern, experimentally grounded mechanisms of production and preservation. We invite contributions addressing any period of Earth’s history—including modern and experimental analogues—that illuminate how microbial processes generate, modify, and record geochemical signals. Together, these studies advance a mechanistic, process-based understanding of microbial life’s imprint on the planet across billions of years.

The Neoproterozoic (1000–538.8 Ma) represents a pivotal period in Earth’s history, characterized by major transitions in atmospheric composition, ocean biogeochemistry, and the planet’s geodynamic evolution. This era witnessed the breakup of the Rodinia supercontinent, accompanied by rifting episodes and extensive subduction zones, and culminated with the Pan-African and Cadomian orogenic events, leading to the formation of the Gondwana supercontinent. These processes coincided with dramatic changes in oceanic and atmospheric composition, including extreme glacial episodes, a rise in atmospheric oxygen levels (the Neoproterozoic Oxygenation Event, NOE), disruptions in geochemical cycles (e.g., C, Nd, Sr) and the emergence of macroscopic ecosystems . This open session welcomes contributions examining Neoproterozoic tectonic, magmatic, orogenic, and paleoenvironmental processes, as well as the interactions between internal and external Earth system dynamics.

Trace element molecular geochemistry aims to integrate measurements of concentrations, isotope ratios and speciation. Black shales record shifts in Earth’s surface redox state and biological evolution. As environmental archives, they connect ocean chemistry, microbial metabolisms, and sedimentary mineralization processes over more than three billion years of Earth history. This session focuses on new geochemical approaches that integrate isotope systematics with trace-metal speciation, redox-sensitive element distributions, and complementary analytical or modelling tools to reconstruct paleoenvironmental conditions preserved in black shales (e.g. molecular geochemistry).

We invite contributions spanning from the Archean to modern restricted basins that use innovative methods such as non-traditional stable isotopes (e.g., Fe, Mo, V, U, Cr, Ni, Cu, and Zn), X-ray absorption spectroscopy, traditional stable isotopes, and/or other novel analytical techniques to constrain redox gradients, element cycling, and diagenetic overprinting in fine-grained sedimentary deposits.

We particularly welcome studies linking isotopic and speciation data to redox processes, hydrothermal fluxes, or the availability of nutrients and metals critical to early life and ocean evolution. By combining diverse geochemical tracers, this session aims to bridge modern, ancient, and experimental perspectives on how black shales illuminate the co-evolution of life, redox conditions, and ocean chemistry through deep time.

The Earth's 4.5-billion-year history provides the most complete record for understanding how life and environment have co-evolved to sustain planetary habitability. This session invites contributions that harness Earth’s geologic and geochemical archives to explore the feedbacks among the biosphere, atmosphere, hydrosphere, and solid Earth that have regulated environmental stability through time. We welcome studies examining how global-scale processes—such as nutrient and redox cycling, primary productivity, weathering, and tectonic activity—have influenced the emergence, expansion, and resilience of the biosphere. Submissions that integrate isotopic, mineralogical, and sedimentary records with modeling or experimental approaches are particularly encouraged. Together, these perspectives can illuminate the mechanisms that stabilized Earth’s long-term habitability and establish principles applicable to other planetary systems. We also invite contributions that extend geochemical frameworks and proxies developed from Earth’s deep-time record to the search for biosignatures and habitable conditions beyond our planet.

Metals (e.g., K, Mg, Ca, Fe, Cu, Ni, Mo, Zn), play fundamental roles in the elemental composition of living organisms as biochemical catalysts, biomineralized structures, and as integral components of information systems, coordinating gene expression and intercellular communication. These elements have played a significant role shaping biological evolution, expanding the metabolic diversity of life, and influencing the chemical evolution of Earth’s surface environments. However, it is unclear whether biological metal usage is a consequence of inherent chemical and biochemical properties, adaptation to changes in environmental metal availability and speciation, or both. Helpful in this inquiry is the observation that interactions between living organisms and metals in the environment can impart distinctive elemental and isotopic signatures on derived materials, potentially leading to long-term geologic preservation of these signatures.

This session aims to highlight research that explores interactions between micronutrient metals and microbial metabolisms throughout geologic time and across geochemical transitions. We invite studies that bring together molecular, physiological, ecological, and/or geochemical perspectives, integrating approaches such as: metalloenzyme modeling, synthesis, and characterization, comparative genomic and phylogenetic analyses, experimental quantification of biological metal usage, investigations of metal bioavailability, and modeling of metal cycling in natural environments. We particularly encourage studies that employ metal stable isotopes to trace microbial processes and microbial influences recorded in geological archives.

By fostering dialogue that bridges disciplines and scales, this session seeks to advance our understanding of how metal availability shapes planetary habitability, and how life and metals have co-evolved throughout Earth’s history.

The Critical Zone represents the dynamic interface where rock, water, air, and life interact to transform minerals and generate soils. Elemental cycling begins with incipient weathering and drives the processes that control nutrient availability, soil formation, and long-term ecosystem sustainability. This session invites contributions that advance our understanding of these transformations across spatial and temporal scales. We particularly encourage studies that employ innovative and integrative geochemical approaches—including, but not limited to, elemental analyses, novel isotope systems, in situ techniques (e.g., laser ablation), and high-resolution imaging—to unravel the mechanisms and rates of elemental mobilization, transformation, and stabilization. Work that comprises experimental, field, or modeling perspectives, and that links fundamental geochemical processes in the Critical Zone to broader environmental and ecological outcomes, is especially welcome.

Critical Zone science integrates diverse disciplines – including geomorphology, hydrology, biogeochemistry, soil science, watershed science, climate science and, increasingly, the social sciences—to advance our understanding of Earth surface processes. In the Anthropocene, watersheds and river networks are increasingly affected by climate change, land use shifts, and other human disturbances, altering erosion, transport, weathering, and elemental cycles from headwaters to coasts.

This session invites contributions that explore Earth surface processes in watersheds through the lens of critical zone science, with an emphasis on forecasting and interpreting hydrological and biogeochemical responses under changing environmental conditions.  We aim to convene scientists from across the globe to share and discuss recent advances in data collection, modelling, and instrumentation for investigating the Critical Zone.

Topics of interest include linkages among:

• Evolution of Earth surface and landscape dynamics
• Chemical and physical weathering and fluxes
• Landslide, erosion, and sediment transport processes
• River network behavior, solute transport, and element fluxes
• Ecophysiological, ecohydrological, and groundwater responses to disturbance
• Glacier and permafrost dynamics
• Implications for resource management
• Urban critical zone

 We encourage submissions that include field observations, experiments, modeling frameworks, and/or simulations. Studies from individual critical zone sites/observatories as well as comparative and cross-scale research are encouraged. We particularly welcome contributions that address scaling challenges or extend critical zone observatory insights to regional or global scale contexts.

Enhanced rock weathering (ERW) is one of the most promising and scalable carbon dioxide (CO₂) removal (CDR) technologies, which accelerates natural rock weathering by spreading alkaline rock powders in terrestrial environments, while also benefiting soils, plants, and ecosystems. Although ERW holds global potential to sequester gigatonnes of CO₂, numerous critical questions remain unanswered, requiring further study and discussion. These include ERW research relating, but are not limited to, variable amendment dissolution and mineralization rates, CDR potential and duration through organic carbon pools, short- and long-term ecological responses, discrepancies in CDR quantified by different measurement, reporting, and verification (MRV) approaches, challenges in CDR monitoring (e.g., lag times induced by cation exchange, strong acid dissolution), and socioeconomic and policy issues such as deployment costs, greenhouse gas emissions, and farmer adoption

We welcome all research related to ERW, including but not limited to: modeling, laboratory, and field studies quantifying CDR through geochemistry, mineralogy, hydrology, soil science, isotopes, and other innovative tools in diverse spatial, temporal, and scale settings; studies assessing ERW impacts on soil–mineral–organic interactions, nutrient cycling, soil chemistry and physics, ecosystems, and agronomy; the role of microbial populations and rhizosphere processes in governing weathering and CDR; MRV methodologies and challenges; CO₂ leakage and life-cycle assessments studies; and research related to scalability, socioeconomic, policy, feasibility, equity, and public acceptance aspects of ERW. This session aims to promote discussion among multidisciplinary experts, foster a comprehensive understanding of ERW, and drive ERW toward large-scale implementation based on rigorous and accurate CDR quantification.

Permafrost and cold-region landscapes are rapidly transforming under climate warming, altering geochemical and biogeochemical cycles from the subsurface to the land–ocean interface. Thaw-driven interactions among minerals, organic matter, microbes, and hydrologic systems enhance the release and transport of carbon, nutrients, and redox-sensitive metal(loid)s, with consequences for water quality, ecosystem health, and climate feedbacks. Simultaneously, glacial retreat and intensified weathering are modifying sediment fluxes and downstream water chemistry across polar and alpine basins.

This session welcomes contributions examining geochemical and biogeochemical processes in permafrost, glacial, and cold-region environments. Topics include element cycling under freeze–thaw and redox-fluctuating conditions, metal(loid) and nutrient mobilization, carbon release pathways, isotopic and geochemical tracers, and modelling or experimental approaches that capture evolving cryosphere-to-watershed dynamics. Interdisciplinary studies linking biological, geological, and hydrological perspectives are particularly encouraged, with the goal of improving understanding of elemental fluxes, landscape evolution, and Earth-system feedbacks in a warming climate.

The land-ocean continuum (LOC), including marginal seas and coastal zones, plays a pivotal role in the global carbon cycle and Earth system dynamics. These transitional realms serve as hotspots of nutrient dynamics, recording high-resolution signals of interactions among the land, ocean, atmosphere, and biosphere. Rising anthropogenic pressure has cascading effects on biogeochemical cycles and may threaten ecosystem function in this critical zone. In Earth's past, non-anthropogenic forcing mechanisms, such as the emplacement of large igneous provinces and Quaternary greenhouse gas variability, likely resulted in similar changes to the LOC.

Geochemical proxies applied to sedimentary archives from the LOC offer unique opportunities to trace environmental transitions across multiple timescales, capturing signals of chemical weathering, carbon cycling, oceanographic change, and anthropogenic influence. However, these archives present challenges related to provenance, diagenesis, and complex depositional settings.

This session promotes interdisciplinary discussions to advance knowledge of LOC biogeochemistry and proxy applications. We invite contributions that: (i) focus on nutrient transport, retention, and interactions along the LOC using geochemical proxies; (ii) utilize novel isotope and elemental systems to reconstruct paleoenvironments; (iii) integrate multiple proxies with numerical and geochemical modeling; (iv) explore feedbacks among climate, weathering, and biogeochemical cycles; and (v) link LOC records with terrestrial and open-ocean processes across timescales. This session aims to refine the understanding of how these critical zones record and respond to environmental and climatic change.

Interactions between the Earth’s surface, the critical zone, and the atmosphere have played a key role in keeping Earth’s climate system within a habitable corridor in which life could develop and evolve. Processes such as silicate weathering, photosynthetic carbon fixation, and the stabilization of carbon in biomass, soils, peatlands, and sediments, along with the transport of inorganic and organic carbon into long-term marine and lithospheric sinks, have collectively shaped Earth’s carbon and climate evolution. During plate convergence and continental collision, buried organic carbon is metamorphosed, oxidized, or recycled into the mantle, influencing global carbon budgets, redox conditions, and climate evolution. Human activity has increasingly altered the fluxes and residence times of carbon among many of these reservoirs. Yet, the links between surface and critical zone carbon cycling, tectonic burial, and deep recycling remain incompletely understood, especially regarding their long-term legacies for the global carbon cycle. This session highlights research that advances understanding of how Earth surface and tectonic processes together influence the carbon cycle across spatial and temporal scales. We invite studies using geochemical, isotopic, mineralogical, geomorphological, and modeling approaches to investigate the stabilization, transformation, and mobilization of carbon, from weathering and sedimentation to subduction and metamorphism. By integrating insights from modern landscapes and ancient orogenic systems, this session seeks to build a holistic view of how plate tectonics and surface processes regulate the burial, transformation, and fluxes of carbon through geologic time and inform strategies for landscape-scale carbon management.

The surface S cycle is central to the evolution of Earth’s redox state, climate, and biosphere. It is governed by a dynamic interplay between atmospheric, lithospheric, and biogeochemical processes and is strongly linked to other elemental (e.g., Fe, C, and O) and trace metal (e.g., Cu, Ba) cycles through complex redox processes. Sulfur redox cycling occurs through a wide diversity of microbial metabolisms (microbial sulfate reduction, S oxidation), assimilatory reactions (biosynthesis), and physical processes in the environment (chemical weathering, photochemistry). The resulting records of organic and inorganic sulfur are critical archives for paleoenvironmental change (i.e., proxies) and the evolution of life (i.e., biosignatures). These archives have been examined for decades using techniques from mineralogy, stable isotope geochemistry, and environmental microbiology. Still, many questions remain about the evolution of the global sulfur cycle and its impact on other element cycles on modern and ancient Earth. This session aims to advance our understanding and quantification of redox processes in Earth’s S cycle in deep time and today. We invite studies from geochemically diverse environments, including marine and terrestrial sediments, hydrothermal vents, and the deep subsurface, from modern to ancient Earth. We particularly encourage submissions that apply novel analytical tools to traditional problems, including but not limited to, the geological history of seawater sulfate, the prevalence of sulfur metabolisms on early Earth, or the contributions of organic sulfur species to long-term carbon reservoirs. These tools include minor isotope (³³S, ³⁶S, ¹⁷O) geochemistry, biomarkers, enzymology, ‘omics’ studies, as well as experimental and computational approaches.

Glaciers and ice sheets play a crucial role in global biogeochemical cycles, harbour unique and potentially fragile ecosystems, and are known to generate vast quantities of reactive sediments. These sediments and associated organic matter sustain subglacial ecosystems and provide macro- and micro-nutrients to downstream environments in lakes, fjords, and oceans. At the same time, glaciers can mobilise potentially toxic elements, raising concerns for ecosystem health. Their role in the global carbon cycle also remains unclear, particularly whether they function as net greenhouse gas sinks or sources. Evidence of widespread glacial methane emissions (biogenic and thermogenic) represent direct sources, which may be offset or amplified by silicate and carbonate weathering reactions, indirect impacts on marine primary productivity, and benthic recycling and remineralisation of glacial carbon.

Understanding the transformations, fluxes and impacts of these bio-essential elements is critical, as polar fluxes strongly influence primary productivity, carbon cycling and global elemental budgets. This knowledge is key for assessing how projected increases in deglaciation will impact global biogeochemical systems.

This session aims to bring together researchers investigating biogeochemical cycles in polar and alpine ecosystems and associated freshwater and marine environments. We welcome contributions from field-based, experimental, isotopic and modelling studies across spatio-temporal scales that: i) quantify the sources, fluxes and magnitudes of nutrients, organic matter and trace elements exported from these ecosystems; ii) study the mechanisms and biogeochemical transformations of these materials before and during export; iii) evaluate their regional and global impacts.

Methane metabolism represents a fundamental set of biogeochemical processes in early Earth, mediating redox transformations between the biosphere, geosphere, and atmosphere. As one of the most efficient biological energy pathways, methane-based metabolisms sustain microbial life in anoxic and extreme environments, regulate Earth’s carbon budget, and serve as analogues for potential metabolisms on other planetary bodies. Advances in cultivation, environmental genomics, isotopic geochemistry, and molecular imaging have revealed a remarkable diversity and evolutionary depth of methane-transforming microorganisms, highlighting the central role of methane metabolism in shaping the Earth system through space and time.

This session invites contributions investigating methane metabolism across molecular, environmental, and planetary scales, encompassing both modern and ancient systems. We welcome studies that integrate physiological, biochemical, isotopic, and modeling approaches to elucidate how microorganisms transform methane and how these processes are recorded as diagnostic biosignatures in sediments, fluids, and the atmosphere. Contributions that link methane metabolism to early Earth environments, deep biosphere energy fluxes, or contemporary carbon–climate feedbacks are particularly encouraged.

By fostering interdisciplinary exchange among geomicrobiologists, geochemists, and planetary scientists, this session seeks to develop a unified framework for understanding methane metabolism as a key process governing biogeochemical cycles and planetary evolution.

Natural organic matter (NOM) in aquatic and terrestrial ecosystems constitutes an integral part of the global carbon cycle and drives many biogeochemical processes. Physicochemical properties of NOM such as heterogeneity and polyfunctionality pose an additional layer of complexity in deciphering the role of NOM across spatial and temporal scales. Additionally, association of NOM with redox-sensitive elements such as iron, sulfur, nitrogen, or manganese can further influence speciation, mineral transformation, greenhouse gas emissions, microbial metabolism and nutrient bioavailability. Therefore, in order to decipher the ultimate role NOM plays in biogeochemical processes, it is essential to elucidate its molecular composition, and its pathways of transformation and decomposition.

This session aims to advance our current understanding of NOM dynamics in aquatic and terrestrial environments, including terrestrial-aquatic interfaces ranging from soil, sediments, wetlands to the seafloor. We invite contributions focusing on the role of NOM in 1) nutrient and contaminant cycling; 2) mineral transformations; 3) greenhouse gas emissions and climate change impacts; and 4) microbial metabolism. Abstracts that examine these topics in the context of climate change are particularly welcome. Laboratory- or field-based experimental studies as well as theoretical modelling, and novel methodological insights including machine learning and artificial intelligence tools that improve our current understanding of the kinetics and pathways of NOM decomposition and transformation are encouraged for submission.

Particle pollutants spanning nanoparticles to microplastics directly influence critical biogeochemical processes, controlling elemental cycling and contaminant fate across Earth's systems. Understanding their environmental impacts requires tracking particles across compartments, from emissions through atmospheric, terrestrial, and aquatic systems, while linking chemical signatures to transformation mechanisms and biogeochemical consequences. This integration of source identification with process understanding is essential for predicting environmental change and developing effective management strategies.

This session emphasizes mechanistic understanding of particulate pollutants behavior through advanced analytical and computational approaches. We particularly welcome contributions demonstrating how methodological advances in one environmental compartment (e.g., atmospheric particle source apportionment, single-particle characterization) can be transferred to trace pollutants in other systems (aquatic, terrestrial, biological materials).

Key topics include:

• Advanced analytical and computational tools: Single-particle techniques, multi-element profiling, AI-driven data processing, and advanced visualization
• Source apportionment and chemical fingerprinting: Statistical modeling and machine learning approaches, elemental/isotopic/molecular signatures, and multi-tracer approaches across particle types and environmental matrices
• Particulate pollutant diversity: From atmospheric aerosols and wildfire ashes to industrial emissions, urban particles, and micro- and nanoplastics, with natural particles (e.g., mineral dust, biological particles) as baselines
• Transformation and transport: Weathering pathways, surface reactions, aging processes, particle mobility across environmental compartments, and source signature evolution
• Environmental impacts: Particle influence of nutrient/contaminant cycles, redox processes, climate feedbacks, ecosystem health

We encourage studies integrating source identification with mechanistic process understanding. Research spanning natural (mineral dust, biological particles) and anthropogenic emissions (urban aerosols, industrial emissions, wildfire ashes, micro- and nanoplastics) is welcome, emphasizing source-to-process-to-impact frameworks.

Carbon plays a central role in regulating Earth’s climate and sustaining ecosystem services, yet many of its reservoirs and their connectivity remain poorly constrained. This session explores the forms, functions, and trajectories of carbon storage and fluxes within ecosystems and geosystems, from soils, peatlands, and permafrost to rivers, estuaries, and marine sediments.

We particularly welcome contributions that apply geochemical and isotopic tracers to reconstruct carbon cycling across spatial and temporal scales. Studies may focus on terrestrial & aquatic paleoenvironmental archives and modern observations that document fluxes, burial, and transformations of carbon. We specifically welcome studies that integrate proxy application and development with modeling, or that combine isotopic, elemental, and molecular tools to highlight “carbon hot spots,” reveal land–sea linkages, and assess climate–carbon feedback. Interdisciplinary approaches that connect past and present dynamics to future projections are especially valued.

Key Themes

• Carbon reservoirs: distribution, connectivity, and vulnerability across terrestrial, aquatic, and marine systems.
• Carbon trajectories through time: transformations and fluxes from deep time to the present.
• Carbon–climate feedbacks: processes linking carbon cycling, disturbance regimes, and climate transitions.
• Methods and tools: isotopic and geochemical tracers, paleoarchives, proxy development, and integrated modeling.

Absent direct detection, confirming the presence of life beyond the Earth will require convergence of multiple lines of evidence to differentiate biosignatures from the abiotic background presence on other solar system bodies and/or exoplanet atmospheres. Terrestrial analogue studies of microbial biosignatures in modern and ancient environments are the means by which these lines of evidence are determined. There are a wide range of analytical and conceptual approaches being applied to these questions. This session will focus on advances in understanding of biosignatures and, in particular, on our ability to effectively resolve biosignatures from abiotic backgrounds using multiple lines of evidence.

Critical Raw Materials (CRMs) are the essential elements and minerals underpinning modern economies. They are deemed critical because they play vital roles in high-tech, energy, defense, and green-transition sectors, yet their supply remains vulnerable to disruption due to scarcity, geographic distribution, and geopolitical conflict. While many studies focus on identifying environmental locations for extraction, the fundamental understanding of their biogeochemical and physical controls—crucial for developing, implementing, and optimizing sustainable mining strategies—remains limited. Advancing this knowledge is crucial to minimize material losses and environmental releases, to optimize reagent use, and to strengthen the overall efficiency of CRM supply chains, ensuring their environmental sustainability and economic resilience. Achieving these goals requires a deep understanding of CRM geochemical reactivity—their speciation in natural and engineered systems, their sorption/desorption mechanisms, and the parameters governing their (co)precipitation and dissolution dynamics. Potential synergistic and competitive interactions among CRMs and other elements must be elucidated.

Aquatic sediments, from coastal wetlands to lakes, estuaries, continental margins, and open oceans are key carbon sinks in Earth’s climate system. From sources to sinks, carbon undergoes cascades of transformations through biotic and abiotic processes. The efficiency of carbon burial and its stability from decades to millennia is governed by these biogeochemical processes. Microbial degradation, redox-driven and physicochemical alterations, interactions with reactive minerals, etc., all determine carbon turnover, burial, and long-term preservation in sediments.

This session invites contributions that examine mechanistic controls on how carbon is processed and preserved in aquatic systems, across land-ocean transects, and below the sediment–water interface. We welcome studies using (not limited to) elemental analyses, porewater chemistry, isotopic tracers, sediment incubations, biogeochemical proxies, spectroscopic and microscopic characterizations, mineralogical and microbiological investigations, as well as machine learning, and modelling. Research into the impact of anthropogenic interventions and submissions that integrate process-level understanding with system-scale to global carbon budgets or climate mitigation potential are also welcomed.

Therefore, by bridging observational, laboratory, modelling and geo-engineering works, this session aims to provide insights into fate and (de)stabilization of carbon, and bring together both industrial and academic perspectives in advancing our understanding of sequestration of carbon in aquatic sediments.

Understanding Earth's surface and planetary systems requires tools that probe mineral-organic-microbe interfaces at the molecular to nanoscale. These interfaces regulate key biogeochemical processes, including nutrient cycling, carbon turnover, and biomineralization, which are closely tied to mineral-organic interactions that modulate carbon cycles, influence the formation and stabilization of organic matter, and control the carbon turnover rate. In particular, they catalyze prebiotic reactions and promote the preservation of biomolecules (e.g., sedimentary ancient DNA) that record environmental and evolutionary histories. Emerging analytical capabilities—from conventional microscopy to synchrotron-based X-ray spectro-microscopy (e.g., STXM, Ptychography, tomography, XANES, EXAFS, XFM)—along with in situ AFM, cryo-TEM, molecular simulations, and protein design approaches, reveal how surface chemistry, hydration structure, and biomolecular binding govern mineral nucleation, transformation, and long-term organic stabilization. This session invites experimental, theoretical, field, and modeling contributions that integrate these complementary methods, as well as conventional methods, to elucidate mineral-organic (e.g., not limited to biomolecule) interactions, biomineralization pathways, and organic preservation mechanisms that shape biogeochemical cycles across Earth and planetary environments.

The biogeochemical cycling of trace metal(loid)s in both terrestrial and aquatic environments plays a central role in regulating ecosystem productivity, elemental speciation, and environmental health. Interactions among microbes, minerals, and dissolved species control the transformation, bioavailability, and isotopic signatures of key trace elements, influencing complex biogeochemical feedbacks from local to global scales. Importantly, trace metal(loid) transformations are tightly coupled to the cycling of carbon, sulfur, and other nutrients, linking redox dynamics and microbial metabolism/detoxification processes to broader ecosystem function. This session unites studies that bridge biological and geochemical perspectives on trace metal(loid) cycling across redox gradients and physical scales—from laboratory experiments to field observations and modeling. We invite contributions examining mineral dissolution and precipitation, redox transformations, the formation of reactive organo-mineral complexes, and methylation–demethylation reactions with a focus on elements including, but not limited to, mercury, uranium, arsenic, selenium, manganese, and iron. We particularly welcome approaches integrating isotopic, spectroscopic, imaging, -omics, biosensor, and modeling techniques to advance molecular understanding of trace element dynamics. By linking microbial and geochemical perspectives, this session aims to provide new mechanistic insights into the speciation and environmental fate of trace metal(loid)s in societally important ecosystems including marine waters, groundwater aquifers, agricultural soils (such as rice paddies), and mining-impacted environments.

Microorganisms are key drivers of biogeochemical cycles. Recent advances in chemistry and molecular biology generate multi-faceted datasets, but challenges remain in interpreting them to predict biogeochemical transformations scaling up from microbial to ecosystem and larger scales. In this session, we aim to attract interdisciplinary studies that combine geochemistry (e.g., aquatic geochemistry, stable isotopes, lipidomics, spectroscopy) and microbial ecology (e.g., culturing, metagenomics, metatranscriptomics) to facilitate our understanding of the functioning and prevalence of biogeochemical processes. We welcome contributions that push the boundaries of our understanding of how microbes and their metabolisms drive environmental geochemistry, including, for example, C, N and Fe cycling. We encourage studies that provide insights on novel organisms, environmental interactions, ecological theory, and model concepts that allow for integration with lab- or field-data across spatial and temporal scales across terrestrial, freshwater and marine systems.

The session celebrates the scientific achievements and legacy of David Emerson, whose work exemplifies the integrative approach we seek. Dave is a pioneer in geomicrobiology who has made extensive contributions to understanding environmental biogeochemistry. Dave’s work - in particular his isolations of novel microbes - has accelerated the discovery of iron oxidation pathways and applies to diverse fields, including steel corrosion, water treatment, astrobiology, Earth history, archaeology, and climate change. Through his work, and the work of many he has trained, collaborated with, and inspired, we have expanded our understanding of biogeochemical cycling across environments. His legacy includes fostering many early career scientists and curating culture collections that enable accessible, reproducible research in geomicrobiology.

Redox processes are fundamental drivers of biogeochemical change across Earth’s critical zone, shaping the cycling of elements, the transformation of minerals, the turnover of organic matter, and the mobility of nutrients and contaminants. These reactions influence soil fertility, water quality, greenhouse gas emissions, and ecosystem resilience. While the molecular-scale mechanisms of electron transfer and coupled mineral–organic matter transformations continue to advance, translating these insights across spatial and temporal scales remains challenging. Natural environments are inherently heterogeneous, and fluctuating hydrological and climatic conditions generate dynamic redox regimes that create spatially and temporally localized reaction “hotspots.” These transient conditions exert outsized control on element cycling and biogeochemical feedbacks, yet their emergent behavior is not fully constrained, underscoring the need for coordinated, multi-scale approaches that bridge laboratory, field, and modeling perspectives.

This session invites contributions that enhance mechanistic and quantitative understanding of (1) mineral transformations and redox heterogeneity in soils and sediments; (2) the fate, transport, and bioavailability of contaminants and nutrients under variable redox conditions; (3) the coupling of elemental cycles and roles of organic matter in driving redox processes; (4) organic matter degradation and greenhouse gas fluxes during redox oscillations; (5) colloid generation and its impact on contaminant mobility; (6) novel analytical and modeling approaches to characterize, scale, and predict redox-driven processes from the molecular to field and global scales.

Global warming disproportionately affects ecosystems of the high-latitude and high-elevation cold regions. The Critical Zone in cold regions comprises components that are particularly vulnerable to warming – snow cover, seasonal frost, and permafrost – as well as soil biota adapted to cold temperatures. Changes in cold regions’ biogeochemistry, hydrology and hydrochemistry are connected to climate feedbacks through greenhouse gas emissions. Research on how cold region microorganisms respond to shifts in environmental conditions is of particular importance for understanding how a warming climate would affect the biogeochemical cycling of carbon, nutrients, metals, and pollutants in the Earth’s cold regions. Meanwhile, warming facilitates the expansion of agriculture, urban growth, and access to natural resources, further adding to the anthropogenic pressures on the cold region ecosystems. The complex interconnection of hydro-bio-geochemical processes in cold regions poses multiple challenges to their realistic representation in earth system models. The cold regions’ Critical Zone therefore requires the integration of process-based investigations with multiscale monitoring and modeling tools. This session focuses on interdisciplinary research that advances our predictive understanding of the biogeochemical processes, microbe-plant interactions, and water quality in cold regions. We welcome presentations that provide new insights into adapted biological activities, hydrogeochemical processes and connectivity in cold region Critical Zone, changes in carbon and nutrient cycling due to climate warming. We particularly encourage the presentations of newly developed laboratory and field methodologies and coupled experimental and modelling approaches that address the impacts of current and future climate warming and land use change on cold region environments.

Colloids, whether originating from natural processes or released through human activities, play a crucial role in the cycling and transport of elements in the environment. Natural colloids are key agents in the mobility of nutrients and trace elements, while anthropogenic nanoparticles, increasingly released into soils, surface waters, and groundwaters can act as emerging pollutants with potentially profound impacts on ecosystems. Understanding the behavior of both types of colloids requires careful investigation of their interactions with dissolved constituents, other particulate matter, and biological organisms. Such insights are vital for predicting the transport of pollutants and trace elements, as well as assessing risks to aquatic and terrestrial systems.
This session brings together research on novel methodologies for studying colloid dynamics in environmental matrices, from advanced analytical approaches to field monitoring strategies. Contributions will address mechanistic studies on the fate and transport of colloidal entities in a broad sense, highlighting processes that govern their distribution and reactivity. By integrating results from experimental, modeling, and monitoring perspectives, the session seeks to provide a comprehensive view of how natural and anthropogenic colloids influence environmental processes.

Water derived from both surface and subsurface reservoirs constitutes the primary source of freshwater for billions of people and underpins the functioning of most terrestrial and aquatic ecosystems. Accordingly, elucidating the origin, pathways, and fluxes of water is essential for safeguarding these resources against contamination and overexploitation. To investigate water movement and transformation processes, a suite of geochemical tracers - including gaseous, ionic, and particulate species - combined with isotopic analyses are used. These methods approaches are fundamental for characterizing the dynamics of natural waters such as rivers, lakes, oceans, and groundwater systems. Moreover, they facilitate the identification and quantification of physical, chemical, and biological processes that critically influence water quality, availability, and ecological integrity.

To advance the integration between empirical observations and quantitative assessments, we invite contributions presenting novel methodological developments in tracer analytics, including but not limited to the determination of ³⁹Ar and ⁸¹Kr, continuous gas monitoring techniques, and membrane-based analytical systems. We also welcome studies employing established tracer approaches to develop or refine numerical models that simulate the evolution of water and other geofluids across spatial and temporal scales.

Furthermore, we particularly encourage submissions that demonstrate innovative model applications incorporating environmental tracer data to improve predictive capabilities regarding water and fluid dynamics in terrestrial environments. Case studies illustrating the application of these tools in environmental and geochemical investigations - especially those enhancing data resolution, expanding spatial coverage, or enabling adaptive field strategies - are highly valued.

Based on the model for surface precipitation by Farley et al. [1] 40 years ago, a single and consistent framework that allows sorption modeling from trace metal adsorption to surface precipitation is available. The present session invites contributions with focus on gathering experimental information and modelling the continuum. The experimental data may range from traditional adsorption investigations, spectroscopic observations over imaging to electrokinetic experiments. Modelling encompasses traditional surface complexation approaches and molecular information. The surface precipitation part is expected to be related to charge reversals in electrokinetic data which could require electrostatic models beyond simple diffuse layer models. We are particularly interested in this aspect. Moreover, we welcome contributions that focus on relating the mechanisms at the molecular scale to the macroscopic observations and the thermodynamic models.

[1] Kevin J Farley, David A Dzombak, François M.M Morel, A surface precipitation model for the sorption of cations on metal oxides, Journal of Colloid and Interface Science, 106 (1), 1985, 226-242.

Dissolved organic matter (DOM) is among the most complex molecular mixtures on Earth, shaping biogeochemical cycles across terrestrial, groundwater, and freshwater systems. As a reactive pool and natural tracer, DOM influences microbial metabolism, contaminant transport, and climate feedbacks. Its ubiquity and sensitivity to environmental change make it an ideal indicator of ecosystem dynamics, resilience, and anthropogenic impacts.

Shifting climates, land-use intensification, and pollution have driven rapid environmental change, demanding innovative tools to characterize DOM. Breakthroughs in mass spectrometry, spectroscopy, and isotopic fingerprinting have dramatically improved understanding of DOM composition, reactivity, and origins. These techniques reveal how molecular and isotopic signatures can track water and nutrient fluxes, predict contaminant fate, and assess ecosystem health. Combined with hydrological modelling and field observations, these methods transform DOM from a passive component into a dynamic storyteller of hydro-biogeochemical processes.

This session explores DOM as both mediator and recorder of environmental change, asking:

• How do emerging techniques (e.g. FT-ICR-MS, NMR, stable/isotopic tracers), reveal links between DOM structure, function, and ecosystem services?
• Can DOM serve as an early-warning system for pollution, eutrophication, or climate-induced shifts in water resources?
• What insights can machine learning and multi-omics approaches provide into DOM’s role in contaminant cycling and carbon sequestration?

We invite contributions including: (i) ultrahigh-resolution or spectroscopic studies of DOM; (ii) investigations of DOM in metal/nutrient cycling, pollutant mobilization, and microbial networks; (iii) applications of DOM as a proxy for system connectivity, hydrological pathways, or responses to disturbances; (iv) integrative work linking DOM with hydrology, ecology, or climate modelling.

Inland waters (rivers, lakes, reservoirs and ponds) are increasingly recognized as hotspots of greenhouse gas (GHG) emissions, mainly carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O), that are driven by complex interactions among physical mixing, redox dynamics, organic matter processing, and nutrient cycling. Recent advances in geochemical measurements, remote sensing, and process-based modeling have improved the capacity of quantifying GHG fluxes. Yet, the spatiotemporal variability of emissions remains highly uncertain, while the physical and biogeochemical drivers (e.g., warming, salinization, eutrophication, land-use intensification) are interconnected, such that how the coupled drivers contribute to aquatic GHG fluxes remain unclear in the context of climate change. Addressing these knowledge gaps is crucial for improving global GHG budgets and informing climate mitigation strategies under the Paris Agreement.

This session will bring together biogeochemists, limnologists, hydrologist and modelers to assess current aquatic GHG emissions and improve the understanding of mechanisms underlying their spatiotemporal patterns across scales, from small ponds to large lakes and along the Land-to-Ocean Aquatic continuum. We welcome contributions that: (1) present field or experimental observations on GHG dynamics and fluxes; (2) investigate biogeochemical processes regulating production, consumption, transport, and emission; (3) develop or apply diverse models to predict current and future fluxes; and (4) utilize novel multidisciplinary approaches that integrate observations, satellite-images and advanced models to assess regional and global GHG emissions.

This session will advance the understanding of geochemical and biogeochemical processes regulating inland water GHG emissions, reduce uncertainties in global budgets, and shed geochemical insights on climate change mitigation.

Scientific Machine learning (SciML) and artificial intelligence (AI) are rapidly transforming the way we model, quantify, and analyze complex behavior and (bio)geochemical interactions and processes within Earth systems. From reactive transport in subsurface environments to multi-scale physicochemical interactions, data-driven and physics-guided approaches are reshaping how we link observations, theory, interpretation, and prediction. Yet, challenges remain in dealing with sparse and heterogeneous data, nonlinear systems, and the integration of physical constraints into ML-based models.

This session welcomes contributions that explore novel ML and deep learning (DL) methodologies applied to diverse complex environmental and geochemical systems. We welcome contributions focusing on techniques involving operator learning, physics-informed neural networks (PINNs), hybrid physics-AI frameworks, uncertainty-aware modeling, and interpretable DL within various scientific applications, including but not limited to fluid flow, reactive transport, coupled processes, geochemical modeling and/or geochemical/hydrogeological data analysis. Furthermore, studies focusing on data-driven approaches to interpret various data and/or accelerate CFD, hydrogeological, or geochemical modeling workflows are also welcome. We encourage submissions ranging from theoretical developments to applied case studies at various spatial and temporal scales.

The goal of this session is to provide a forum for the growing scientific community at the intersection of Earth sciences, reactive transport, geochemical modeling, and ML. We aim to foster dialogue, collaboration, and new frontiers in understanding the dynamics of complex natural systems.

Freshwater salinization is a global issue with a multitude of causes including: road salt application, fertilizer application, wastewater discharge, climate change-enhanced mineral weathering and/or evaporation and desiccation, mining, construction, and seawater intrusion. Salinization can be a major perturbation to (bio)geochemical cycling, hydrodynamics, and biota in freshwater environments. Understanding the diversity of the causes, extent, and trends in freshwater salinization as well as the interactions with freshwater geochemistry will help to identify the commonality among geochemical responses to salinization in freshwater systems. This understanding can guide freshwater managers to understand the potential additional geochemical consequences of salinization and to design effective measures for mitigating or cleaning up freshwater salinization.

This session invites contributions about the causes, extent, and cumulative and coupled impacts on (bio)geochemistry of freshwater salinization. This session will advance the understanding of the geographic extent and diversity of the freshwater salinization problem globally. Topics could include: spatial or temporal analyses of salinization within or across watersheds; lab-scale and field-scale investigations into the interactions between mineralogy, biogeochemistry and hydrology in groundwater and/or soil during salinization. Field, laboratory, and/or modeling studies done at any scale are all welcome.

Mining sustains the global economy and the energy transition, yet extraction and processing-amplified by climatic and hydrological perturbations-drive complex water-quality challenges. Heavy metals transform and migrate across the rock-soil-vadose-groundwater-surface-water continuum. Deciphering their isotopic composition, speciation, interfacial reactions, sources, and fluxes is essential for robust risk assessment and effective, sustainable water management in mining regions.

This session integrates two complementary themes: (1) mechanistic understanding of metal transformation and transport from sources (waste-rock piles, tailings storage facilities, host rocks) through soils and aquifers to springs, hyporheic zones/baseflow, rivers, sediments, and wells; and (2) advances in isotopic and geochemical tracer methods that illuminate subsurface flow paths, water age and mixing, water-rock interactions, and biogeochemical processing. We particularly welcome innovative applications of stable, radiogenic, and noble-gas isotopes and trace-element fractionation, including non-traditional stable isotopes (e.g., Li, Mg, V, Fe, Ni, Cu, Zn, Mo, Sb, Sn, W, Hg, U), alongside novel characterization techniques and multi-scale hydrogeochemical modeling.

By convening field and laboratory studies from micro to regional scales, the session aims to translate new process-level insights into actionable strategies across the source-pathway-sink-impact-remediation continuum-covering source reduction, pathway interception/attenuation, and end-of-pipe treatment-to enhance water security and water quality under changing environmental conditions.

Groundwater and freshwater systems are increasingly challenged by both legacy pollution from past land use and emerging contaminants linked to modern agricultural and industrial practices. Nutrient enrichment, pesticides, antibiotics, PFAS, and other contaminants interact with hydro-biogeochemical processes in complex ways, influencing water quality, greenhouse gas fluxes, and ecosystem function. Long residence times and heterogeneous flow paths can mask or delay water quality responses to management actions, while shallow systems such as ponds, riparian wetlands, and hyporheic zones act as dynamic reactors that may transform, store, or release nutrients and contaminants. Better understanding is needed of the coupled physical, chemical, and biological processes that regulate contaminant fate and nutrient cycling across groundwater–surface water interfaces and at the catchment scale. Compound-Specific Isotope Analysis (CSIA) is a powerful tool to provide insights into contaminant sources and transformation mechanisms and has been successfully applied to quantify the degradation extent of legacy contaminants. Method development (e.g., preconcentration techniques, Orbitrap-MS) continues to be proposed for emerging contaminants at environmentally low concentrations, with a strong potential to provide concrete evidence of contaminant dynamics and in-situ transformation in groundwater systems.

We invite contributions that integrate field observations, laboratory experiments, isotopic and geochemical tracers, and reactive transport modeling to assess the occurrence, transformation, and fluxes of nutrients and emerging contaminants. We also welcome submissions including advances and applications of CSIA to improve our understanding of contaminant dynamics in groundwater and freshwater systems.

Understanding the complex interactions between soil, water, and subsurface geochemical processes is essential for designing effective remediation strategies in contaminated landscapes. This session aims to highlight recent advances in hydrogeological and geochemical characterization techniques that improve our understanding of contaminant transport, transformation, and natural attenuation in soil–water systems. With increasing anthropogenic pressure from agriculture, mining, and industrial activities, contaminants such as heavy metals, nitrates, and organic compounds are progressively altering the hydrochemical equilibrium of aquifers and soils. Integrating hydrogeological investigations with geochemical fingerprinting, isotopic tracing, and reactive transport modeling offers new perspectives for developing nature-based and engineered remediation approaches tailored to specific hydrogeological settings.

This session will bring together researchers, practitioners, and policymakers working on groundwater quality, soil remediation, aquifer restoration, and sustainable land–water management. Emphasis will be placed on linking field investigations, laboratory experiments, and numerical modeling to achieve holistic characterization and remediation design.

Key sub-themes

1. Hydrogeological investigations for contaminant transport and groundwater–soil interaction.
2. Geochemical and isotopic characterization of polluted aquifers and vadose zones.
3. Soil–water interface processes affecting contaminant mobility and speciation.
4. Reactive transport and geochemical modeling for prediction and remediation planning.
5. Natural attenuation, redox zonation, and microbial interactions in soil–water systems.
6. Monitoring and assessment tools – from field sensors to remote sensing and AI-driven analytics.
7. Sustainable remediation and restoration strategies, including phytoremediation, biochar applications, and permeable reactive barriers (PRBs).
8. Policy frameworks and risk assessment approaches for contaminated land and groundwater management.

Exploration, development, and utilization of energy and mineral resource leave lasting geochemical imprints on the environment that directly and indirectly affect human health. For example, mining, smelting, fossil fuel combustion, and waste disposal release metals, metalloids, and organic contaminants that alter natural geochemical cycles, mobilize toxic species, and degrade water and soil quality. This session aims to highlight the application of geochemical knowledge and tools to environmental and health issues, both legacy and incipient, from our use of energy and mineral resources, particularly in face of our rapid transition from fossil fuels to renewable energies and correspondingly increasing demand for critical minerals. We invite contributions from field, laboratory, and/or modelling studies on contaminants associated with energy and mineral resources. Relevant topics include, but are not limited to, (i) geochemical distribution of contaminants across temporal and spatial scales, (ii) geochemical signatures and/or tracers for contaminants, (iii) geochemical processes governing the mobility, transformation, and/or long-term fate of contaminants, and (iv) geochemical feedback between contaminant fate and health risks. Policy-related contributions to environmental protection and/or resource management are also welcome.

Stable isotopes—spanning traditional light elements (C, N, O, S) to non-traditional metal and metalloid systems—have become indispensable tools for unraveling complex chemical processes across both environmental and biological systems. As Earth experiences accelerating changes from natural and anthropogenic forces, and as human health challenges grow in scale and complexity, isotope science offers a unique bridge for understanding how elements move, transform, accumulate, and influence living organisms and their surroundings.

In environmental contexts, stable isotopes help identify contaminant sources, track their transport across air, water, soil, and biota, and quantify biogeochemical transformations that shape exposure risks. Within organisms, these same elements undergo additional isotopic fractionation during physiological processes, metabolism, and disease progression. Such biologically driven isotope effects are emerging as powerful indicators of pathophysiology, offering new avenues for diagnosing, prognosing, and monitoring major diseases—from cardiovascular and metabolic disorders to cancer, neurodegeneration, and kidney disease.

This session highlights innovative research that leverages isotope geochemistry to advance both environmental understanding and human health sciences. We welcome contributions that explore:

• Experimental, theoretical, or modeling studies elucidating isotope fractionation mechanisms in environmental or biological systems;

• Isotopic tracing of contaminant origins, environmental fate, and exposure pathways;

• Applications of stable isotopes to characterize metabolism, toxicity, or physiological processes in cells, animal models, or humans;

• Development and clinical evaluation of naturally occurring isotopic biomarkers for disease detection and monitoring of treatment efficacy;

• Interdisciplinary approaches combining isotope geochemistry with emerging technologies—including big data analytics, AI/ML, imaging, and numerical simulations—to address complex environmental and biomedical challenges.

Understanding the sources, transformations, and fate of greenhouse gases and contaminants is critical for addressing global challenges in environmental and climate research. This session explores both anthropogenic and natural contributions to emissions of methane, carbon dioxide, nitrous oxide, organic and trace metal contaminants, with a focus on molecular-level isotopic techniques that enable accurate source attribution and process characterization. Specifically, we invite contributions that apply compound-specific isotope analysis (CSIA), clumped isotope, and position-specific isotope analysis (PSIA) to investigate emissions or pollution from industrial, agricultural, and urban activities, as well as natural systems such as wetlands, geothermal environments, marine and lacustrine sediments, and mineral springs. Studies that integrate isotopic data with geochemical modeling, field observations, and laboratory experiments to elucidate contaminant pathways and transformations in natural and engineered environments are encouraged.

As populations expand and develop, protecting public health requires an integrated understanding of geochemical processes, contaminant sources, and human exposures. This session brings together researchers working across drinking-water systems, urban landscapes, and contaminant-impacted environments to explore how elemental behavior and isotopic fingerprints illuminate pathways of contamination, transformation, transport, and mitigation, and their implications for public health.

We invite studies that investigate geochemical processes controlling the occurrence, mobility, and fate of metal contaminants in water (e.g., groundwater/well water, surface water, water systems), soils, air, and urban settings. Contributions can highlight natural and anthropogenic metal contaminants and/or the application of traditional and emerging metal isotope systems (e.g., Pb, Sr, Nd; Zn, Cu, Fe, Li, Cd, Hg) to trace contaminant sources and quantify biogeochemical processes. We are particularly interested in novel applications of isotopic tools and other advanced analytical approaches to advance understanding of urban geochemistry and its links to environmental and human health.

We welcome abstracts spanning fundamental process studies, analytical and methodological innovations, and applied research connecting geochemistry to exposure, health outcomes, and policy in urban contexts.

This session, organized in honor of Professor Laurent Charlet, will showcase innovative research inspired by Laurent’s groundbreaking contributions to environmental geochemistry, medical geology and beyond. With a career spanning multiple disciplines, Laurent exemplified a rare ability to connect the microscopic with the macroscopic—whether probing molecular-level interactions or addressing global environmental concerns. We invite submissions on topics that reflect his diverse scientific legacy, from the aqueous and solid speciation of inorganic and organic contaminants , the redox reactivity of iron of iron minerals, to surface reactivity of phyllosilicate minerals and the geochemistry of nuclear waste and its implications for long-term storage. We encourage studies exploring the broader impacts of geochemistry on human health, a reflection of Laurent’s forays into medical geology. Researchers from diverse backgrounds are invited to contribute new findings that echo the intellectual curiosity and innovative spirit that defined the works by Laurent, pushing the boundaries of geochemical understanding and its applications.

Persistent organic pollutants such as micro and nanoplastics, perfluoroalkyl substances, polychlorinated compounds, textile dyes etc., have become an emerging component of Earth’s biogeochemical processes, interfering several natural processes that regulate the cycling of elements and adversely impacting ecosystems. Their individual presence or their concomitant presence with other pollutants (cocktail effect) will make the system more complicated due to underlying synergistic effects in the environment. The degradation of polymers into reactive micro- and nanoplastics to their interactions with natural components such as minerals, metals, organic matter or with other pollutant cocktails is a function of complex geochemical entities influencing redox equilibria, sorption dynamics, and biogeochemical fluxes.

This session focuses on the environmental accumulation (through aquatic systems, air, soil and sediments), transformation and human exposure (water, air and food) pathways of the aforementioned pollutants. We invite studies combining experimental geochemistry, spectroscopy, isotope techniques, modelling, environmental assessment studies and field-based observations to unravel pollutant cocktail–mineral–microbe interactions and their role in pollutant mobility and ecosystem processes.

Recognizing the human dimension of this challenge, the session also welcomes contributions examining behavioural and socio-geochemical linkages — how patterns of production, consumption, and waste management govern plastic accumulation and its environmental imprint.

By integrating perspectives from geochemistry, environmental materials science, and social–ecological research, this session aims to advance a unified understanding of persistent organic pollutants and potentially toxic heavy metals as a reactive geochemical system shaped by both natural processes and human behaviour.

Pollution poses wide-ranging risks to human and ecosystem health. In many regions, increasing wildfire activity has become a growing driver of pollution, releasing mixtures of particulate matter, gases and trace metals that can be transported over long distances. These emerging threats add to long-standing sources and the history of metal pollution linked to mining, metallurgy and industrial processes, creating complex exposure pathways for people and the environment.

Metals have played a central role in human cultural evolution, but their use and misuse have also harmed past societies. Legacy pollution may be associated with medical practices, cosmetics, artistic materials and funerary traditions. This makes metal pollution both an ancient and a contemporary problem. Today, many parts of the world continue to face environmental degradation and social conflict related to metal contamination from mining and metallurgical activities, now compounded by changing climate conditions and more frequent wildfires.

This session provides a forum to discuss the historical and present dimensions of pollution, including its impacts on humans, animals, communities and ecosystems (One Health approach). We welcome case studies and reviews on emerging and historical contaminants, as well as long-term reconstructions of metals and metalloids in natural and cultural archives. Contributions using multidisciplinary and transdisciplinary approaches, such as modelling, isotopic tracing and novel analytical methods, to identify anthropogenic- and naturally derived contamination are encouraged. By integrating archaeological, geological, biological and chemical evidence, this session aims to deepen our understanding of pollution across time and space and to advance methods for identifying pollutants.

Groundwater and surface water are the primary water resources for agriculture, industrial activities, and domestic use. The intensive use of chemicals in past decades combined with inadequate waste management resulted in many contaminated sites worldwide. Heavy metals, pesticides, nanoparticles, microplastics, pharmaceuticals and industrial effluents are contaminating water resources at increasing rate. Land application of biosolids and reclaimed water for agriculture poses a significant source of contaminant mixtures to soil and water. Human exposure to water and soil contamination may cause adverse effects such as cancer, neurotoxicity, and endocrine disruption. Conventional water and soil decontamination approaches, especially those used at contaminated sites, are often expensive, energy-intensive, and inefficient in reaching remediation goals. Given the typically persistent nature of a range of contaminants, the development of novel (nano)materials and approaches are being investigated at a range of scales (e.g., from basic laboratory research up to pilot-scale evaluation). 
We encourage submissions related but not limited to molecular modeling, material preparation and characterization, field or laboratory experiments dealing with physical, chemical, and/or combined elimination of water/soil pollution, and detection and state-of-the-art monitoring of pollutants in the environment. The aim of this session is to address advances in a preparation and characterization of new (nano)materials and technologies, and their applications in innovative remediation processes, for example, removing and elimination of both legacy and emerging contaminants (e.g., toxic metals and metalloids, chlorinated ethenes, PCBs, PFAS, halogenated pharmaceuticals and pesticides), in different matrices such as surface water sediments, groundwater, and surface or agricultural soils.

Both radiogenic (e.g., Pb, Sr, Nd, Os) and non-traditional stable (e.g., Sn, Cu, Ag, Hg, Sb) isotopic systems have become widely applied to inorganic archaeological materials for inferences of geological source(s) and to help reconstruct aspects of their production. Large databases of geological materials (including TerraLID) are now contributing to the growth of these analyses and helping increase access to necessary data for their interpretation. Despite this rise in the use of these techniques and the resources available to these studies, the interpretation of isotopic ratios in archaeological materials is often attempted without a clear understanding of how geological processes produce natural variation, or how technological processes (smelting, alloying, recycling, mixing, etc.) can alter isotopic ratios of natural materials. We therefore invite papers which address these issues, and which incorporate geological and/or technological foci for the interpretation of isotopic data in inorganic archaeological materials.

Wildfires, volcanic eruptions, and dust storms are events that emit massive quantities of smoke, ash, and fine particles as atmospheric inputs. These particles have the potential to circulate around the globe, redistributing heat and incoming radiation, altering the evolution of clouds, and transporting carbon and nutrient materials out of their area of emission. Their impact extends throughout the entire Earth system, changing atmospheric chemistry, as well as affecting ecosystems and climatic patterns on both short and long time scales. 

With ongoing increases in global temperatures, the frequency and magnitude of these events are projected to increase accordingly, so there is great value in improved understanding and prediction of their effects. This session seeks contributions that investigate how extreme events affect the atmosphere and climate, from transport pathways and chemical transformations to other aspects such as carbon, energy, and nutrient cycles. We welcome studies based on field experiments, laboratory investigations, satellite retrievals, historical datasets, and modeling frameworks. Research constructing or using prediction frameworks—such as Earth system models and machine learning—is of particular interest. By integrating perspectives from geochemistry, climate science, and atmospheric research, this session will explore how extreme events connect the atmosphere, oceans, and biosphere, and what their growing prominence reveals about the future of the Earth system.

This session honors Alfonso Mucci, Emeritus Professor of Geochemistry at McGill University (Montreal), who recently retired. His outstanding contributions to chemical oceanography continue to inspire and guide the scientific community. Professor Alfonso Mucci also served as Chair of the Scientific Committee for the 2012 Goldschmidt Conference in Montreal. In this 2026 edition of the conference, this gathering offers a special opportunity to reconnect with his former collaborators, students, and others who were inspired by his scientific legacy.

Throughout his career, Professor Alfonso Mucci made pioneering advances in various scientific fields, including carbonate mineral solubility, benthic biogeochemistry, the cycling of biogenic elements and trace metals, and issues related to the impact of human activities on ocean chemistry. These topics resonate strongly with his most recent work on ocean acidification and coastal hypoxia. This session will explore various aspects of chemical oceanography, with a particular focus on natural processes that drive or mitigate acidification or hypoxia in the ocean and other natural aquatic environments. We especially welcome contributions that investigate biogeochemical and physical processes that generate fluxes of alkalinity, organic carbon, or other biogenic compounds at the water-sediment interface from intertidal environments to the deep ocean.  Submissions addressing innovative approaches to counteract ocean acidification by ocean alkalinity enhancement (OAE) are also welcome.

Trace elements and isotopes (TEIs) play essential roles in the ocean, serving not only as micronutrients, but useful tools for better understanding marine biogeochemistry. Their distributions are strongly influenced by boundaries - regions where physical, chemical, and biological gradients intersect to control redox states, speciation, and particle reactivity. This boundary concept encompasses large-scale interfaces (e.g. atmosphere-ocean, seafloor-ocean, land-ocean), and biogeochemical gradients, including redox fronts, Oxygen Minimum Zone (OMZ) - oxygenated transitions, particle-seawater microenvironments, and organism-associated microscale habitats (e.g., phycospheres, benthic ecosystems), where intense exchange is mediated by chemical gradients and biological activity. At large-scale ocean interfaces, inputs from natural and anthropogenic pathways, rapid transformations (oxidation, complexation, adsorption), and burial occur, thereby modulating oceanic TEI residence times. Within the water column, sharp redox boundaries (e.g., at OMZs) regulate the solubility, mobility, and bioavailability of several TEIs (e.g., Fe, Co). At the microscale, particle surfaces and organic exudates define reactive microenvironments that control adsorption-desorption dynamics and trace metal speciation. Additionally, the boundary between seawater and microorganism cells control metabolic processes and the internal cycle of TEIs. Recognizing this spectrum of boundaries highlights the interconnected pathways shaping TEI distributions across spatial scales, helping to disentangle the importance of bottom-up versus top-down controls. Integrating processes from global interfaces to microscale gradients is thus essential for predicting how marine TEI cycling responds to climate change and anthropogenic perturbations. This session welcomes field observations, laboratory experiments, and modelling studies to gain further understanding on how different ocean “boundaries” control TEI distributions.

Seafloor hydrothermal systems have profoundly influenced Earth’s biosphere, lithosphere, hydrosphere, and atmosphere 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 efforts that integrate studies of modern systems, interpretations 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 the role of seafloor hydrothermal processes in the Earth system. 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 seafloor hydrothermalism in carbon and other elemental cycles, studies of the linkages between hydrothermal alteration, crustal mineralogy, and seawater geochemistry, and the relation between hydrothermal systems and the tempos and milestones of biological evolution.

Dissolved oxygen in the surface ocean is rapidly declining as climate change accelerates, and the extent of low-oxygen waters has increased as a consequence. In order to contextualize our present and make reasonable projections into the future, we must develop a better understanding of present forcing and past ocean oxygenation, the relationships between ocean oxygen and global climate, and the impacts of changing ocean oxygen on marine life, geochemical cycles and the blue economy. Geochemical tools and biogeochemical models have proven invaluable for enabling us to assess the present, to develop records of past ocean oxygenation and low-oxygen environments using a wide range of proxies and models, and to project future oxygen distribution in ocean and potential impacts. This session invites submissions that advance an understanding of present, past and future ocean oxygenation with diverse approaches including measurements, modeling, proxy development and applications. We welcome submissions across all temporal and spatial scales, and especially encourage studies that benefit from synergies between modern and paleo-oceanography, geochemistry, sedimentology, and modeling.

The last two decades have seen major advances in our understanding of the long-term (geological) carbon cycle and how this regulates Earth climate. The textbook version of the carbon cycle posits that variations in volcanic and metamorphic degassing drive changes in atmospheric CO₂ and climate, which lead to changes in the rate of alkalinity production via continental silicate weathering and carbonate burial on the seafloor. This negative feedback has been hypothesized to maintain planetary habitability since the Archean. However, recent work has questioned this framework and led to development of more nuanced perspectives of continental weathering, new models of the role of organic carbon cycling, and new insights into the role of the seafloor through submarine basalt weathering and reverse weathering. Additionally, the role of ocean chemistry in controlling the partitioning of carbon between the ocean and atmosphere on long timescales has been emphasized as a control on pCO2. The magnitudes of carbon cycle fluxes key to regulating the geologic carbon cycle today and in the past also remain under-constrained, although new proxies and approaches are enabling improved estimates. This session invites contributions that highlight new advances across multiple fields in the Earth sciences and using diverse approaches, including in theoretical modeling, field-based observations, and proxies, that address the standard and alternative models of the regulation of the long-term carbon cycle.

It is unlikely that CO₂ emission reductions will be sufficient to keep Earth’s climate within 2^oC of pre-industrial global average temperatures. In addition to drastic emission reductions, Carbon Dioxide Removal (CDR) on the scale of 10 to 20 Gt CO₂/yr will be required by mid- to late-century. Among potential ocean-based technologies for CDR, Ocean Alkalinity Enhancement (OAE) is emerging as one of the most scalable and durable. Several proof-of-concept studies and pilot deployments have been conducted during the past few years in this rapidly growing field and the first carbon credits for OAE have been issued in 2025. Although momentum is building for larger-scale OAE deployments, research is urgently needed to investigate its viability, efficiency, and environmental impacts. The physical and biogeochemical complexity of the ocean presents challenges to both research and operational deployments that require a combination of laboratory experimentation, ocean measurement, and modelling. Mechanistic insights into relevant processes such as secondary precipitation are emerging from targeted experimentation in the laboratory. Evaluations of ecosystem responses are being conducted across a range of scales from beaker to mesocosm. Various modelling approaches, and their integration with ocean observations, are being pursued. We invite contributions across a broad range of approaches (including bench-top, modelling, and coastal and open ocean experiments) and scales (from particle-environment interactions on micrometers to meters, to local and regional field and modelling studies, to Earth system modelling) with the objective of showcasing the current state of knowledge and facilitating exchange of information at the cutting edge.

The chemical composition of seawater—major and trace elements, isotopic compositions, alkalinity, redox conditions, pH, and salinity—has varied throughout Earth's history. These changes record the complex interactions among Earth's spheres and provide key insights into the evolution of biosphere habitability, fluctuations in atmospheric oxygen and carbon dioxide levels, shifts in lithospheric composition and weathering, and material cycling between Earth’s interior and surface. Documenting the long-term variations in seawater chemistry, understanding the key drivers behind these changes, and their quantitative links to geological processes greatly advance our knowledge of Earth's surface system evolution and long-term habitability.

This session invites studies that reconstruct seawater chemistry across various timescales and explore its implications for interactions among Earth's spheres. We welcome work that address the evolution and controls of seawater chemistry in the geological record through the development and application of marine geochemical proxies and archives (e.g., Li, Sr, Mg, Ca, SO₄, Cl, B, C, P, REEs; redox and pH indicators, etc.), as well as studies employing experimental simulations, data integration, numerical modeling, and big data analysis. Our goal is to foster a comprehensive understanding of secular variations in seawater chemistry and links to key geological processes across Earth's spheres, biogeochemical cycling, and climate change.

To limit global warming to below 1.5°C, reducing carbon dioxide alone is insufficient—short-lived climate forcers (SLCFs) must also be addressed. SLCFs, including aerosols (e.g., black carbon, sulfate) and reactive gases (e.g., methane, ozone), have brief atmospheric lifetimes but exert strong warming or cooling effects while degrading air quality. Recent advances in isotope geochemistry and atmospheric chemistry have unveiled their complex interactions with climate and ecosystems, as highlighted in IPCC AR6.

This session showcases cutting-edge research on SLCFs, integrating isotopic techniques, field observations, lab experiments, and modeling to trace sources, unravel atmospheric processes, and quantify impacts. We invite contributions on:

• Source attribution using isotopic and geochemical tracers
• Atmospheric processing and biogeochemical cycling of SLCFs
• Climate and health impacts, including radiative forcing and pollution linkages
• Policy-relevant insights for co-beneficial mitigation strategies

Topics span method development, multi-scale modeling, and interdisciplinary approaches to advance SLCF science. By bridging gaps between climate and air quality research, this session aims to inform effective policies for near-term climate mitigation and sustainable development.

Naturally occurring radioisotopes and constant flux proxies have revolutionized our ability to quantify and reconstruct vertical particle settling and sediment deposition rates across a variety of modern and past oceanographic conditions. These geochemical tracers, including U-series isotopes, extraterrestrial helium-3, meteoric beryllium-10, and other isotopes with predictable production rates or input functions, have thus enabled refined investigation into dynamic processes such as aerosol deposition, continental input, ocean circulation strength, water mass changes, hydrothermal metal fluxes, biologic productivity and carbon export. Yet, as constant flux proxies become more widely measured, fundamental questions remain regarding when, where, and how the mechanics of each proxy system may or may not work as assumed and what information can be inferred when distinct proxies yield disparate results. 

This session invites observational and modeling contributions regarding recent applications, insights, and identified complications of naturally occurring radioisotopes and constant flux proxies applied in modern or paleoceanographic environments.

Ocean circulation and the global carbon cycle are fundamental components of the Earth system, regulating climate through redistributing heat, nutrients, and carbon in the ocean. During past climate transitions across various timescales including but not limited to millennial-centennial rapid changes, glacial–interglacial cycles, and more gradual long-term cooling/warming, changes in ocean circulation are thought to have profoundly affected the partitioning of CO₂ between the ocean and the atmosphere. Understanding associated processes is pivotal to decipher mechanisms underlying both abrupt and long-term climate changes.

This session aims to synthesize studies that explore how variations in ocean circulation, biological processes, and marine carbon shifting interacted under different climatic states during the Cenozoic. We invite contributions including reconstructions of water-mass geometry and dynamics (e.g., current strengths, ocean stratification, ventilation state), nutrient and carbon cycling using both proxies and models that elucidate feedbacks between ocean dynamics and climate. Submissions investigating changes in polar (e.g., air-sea CO2 exchange, sea ice dynamics) and low-latitude (e.g., atmospheric CO2 reconstructions at critical climate transitions) regions are welcome. We also encourage data-model integration studies to reach a holistic understanding of the ocean–carbon–climate system through time.

Speleothems (cave carbonates) continue to transform our understanding of Earth’s past environments, offering precisely dated, high-resolution archives of climate, ecosystem, and hydrological change. Recent advances in analytical techniques, proxy system modeling, and experimental approaches are pushing the frontiers of what can be learned from these important archives. This session invites contributions spanning the full spectrum of speleothem science, from fundamental process studies to innovative proxy applications. We particularly encourage studies that develop and calibrate novel geochemical or isotopic proxies for reconstructing paleotemperature, soil and vegetation dynamics, and hydroclimate variability.

We welcome contributions that integrate field-based cave monitoring, laboratory experiments, and modeling of carbonate precipitation and trace element incorporation to better constrain the climatic and environmental signals encoded in speleothems. Advances in crystallochemistry, crystal microstructure, and growth kinetics are shedding new light on the physicochemical controls of speleothem formation, while proxy system models and isotope-enabled climate models are enhancing our ability to interpret complex signals from cave archives in the context of past and future climate change. We also encourage interdisciplinary submissions that link speleothem data to other terrestrial, marine, or ice-core records, and studies that explore data assimilation, uncertainty quantification, and/or novel dating approaches.

Variations in Earth’s orbit, axial tilt, and precession drive changes in atmospheric, oceanic, and terrestrial thermal gradients, resulting in shifts in climate regimes that are imprinted in the geologic record. A thorough understanding of these linkages enables not only the correlation of past climate variations with orbital parameters but also the reconstruction of high-resolution chronologies between temporal markers. The identification of Milankovich cycles in the sedimentary record forms the basis of cyclostratigraphy, providing high-resolution chronological constraints, potential basin-wide correlations, and insights into the timing of past environmental changes. Additionally, unraveling the rhythm of orbital parameter variations throughout Earth’s history enables the reconstruction of the dynamics of the Earth–Moon system. This session particularly encourages contributions that integrate geochemical tracers with orbital forcing to interpret paleoclimate; studies that use proxy records tuned to orbital configurations to perform stratigraphic correlations and establish precise chronological frameworks basin-wide; studies that perform age-depth models using orbital tuning; and research that examines the Earth–Moon system throughout geologic time. 

Tracking changes in ocean nutrient cycling through time is essential to understanding the dynamic interactions between ocean, climate, and other Earth systems, particularly in the context of past, present, and future climate change. Nutrients play key roles in regulating biological productivity, atmospheric composition, and global climate feedbacks. Geochemical tools, including stable and radiogenic isotopes, elemental ratios, and redox-sensitive trace elements, offer powerful means to reconstruct how nutrient cycles have evolved across timescales ranging from the modern era to deep geologic time.

Marine geochemical proxy records, instrumental observations, and model output provide information on how nutrient cycling has responded to a wide range of perturbations, including both natural variations and anthropogenic influences. For example, these approaches provide insights into the mechanisms driving nutrient redistribution, ocean anoxia, carbon burial, and greenhouse gas fluxes over different timescales. 

This session invites contributions that explore innovations in geochemical proxies, modeling, and field observations aimed at tracing nutrient transformations and fluxes. We encourage studies from diverse marine environments and across temporal scales. By bringing together modern biogeochemical perspectives with paleo-records, this session seeks to advance our understanding of how Earth’s nutrient cycles respond to and influence global climate systems.

The geochemical composition of biogenic minerals largely reflects the environmental conditions in which they precipitate, forming the basis of many proxies used for climate reconstructions. These geochemical signals, however, are also influenced by biological and inorganic processes during biomineralisation, and may also be overprinted by diagenesis after sedimentation. The nature and relative influence of these factors remain insufficiently constrained, posing challenges to the interpretation of biomineral proxies in many cases.

Therefore, this session aims to explore the mechanisms shaping the geochemical signatures recorded in (bio)minerals. We welcome contributions involving geochemical, microscopic, spectroscopic, and structural studies of the formation, transformation, and alteration of (bio)minerals. This includes experimental approaches through inorganic precipitation and culturing of calcifying organisms, as well as modelling studies that advance our understanding of the incorporation processes of trace element and isotopic signatures. We encourage an interdisciplinary discussion, integrating diverse perspectives of biomineralisation and proxy development to advance a mechanistic insight into biomineralisation. This knowledge will help refine the application of proxy signals for paleoclimate reconstruction and, in turn, provide the necessary knowledge for future climate predictions.

This session will explore organic geochemical approaches for reconstructing paleoclimates and paleoenvironments. These approaches invariably involve evaluating the distributions and/or isotopic composition of specific lipid biomarkers or the characteristics of complex organic mixtures in climate archives. The molecular and isotopic composition of organic matter reflects its complex relationship to ecosystems, depositional settings, and the environment arising from a range of physiological and ecological factors that govern biosynthetic process and carbon uptake during production of organic matter. These primary biological signals can experience a wide variety of changes associated with (bio)degradation, deposition, diagenesis, and transport, while preserving critical evidence of their environment.

We welcome submissions applying organic geochemical proxies to reconstruct (extreme) terrestrial and marine paleoenvironments and biogeochemical cycles, including measures of temperature, redox conditions, vegetation dynamics, food webs, soil pH, and atmospheric CO₂; advancing methodologies for extraction, quantification, and identification of organic matter and isotopes; validating novel organic geochemical and isotopic proxies; and examining factors associated with diagenetic processes and the preservation of organic matter. We encourage abstracts describing applications of conventional, unconventional, and novel proxies.

Ocean circulation and ventilation are crucial in regulating the Earth’s climate system, controlling the distribution of heat, freshwater, oxygen, and nutrients, and modulating the exchange of carbon between the ocean and the atmosphere. Throughout the Cenozoic and Quaternary, reorganizations of overturning circulation, such as the AMOC, Southern Ocean upwelling, Pacific ventilation, Indian Ocean circulation, and Indonesian Throughflow, have influenced monsoons, oxygen minimum zones, and global biogeochemical cycles, with major implications for past and future climate change. This session seeks to advance understanding of the drivers, mechanisms, and consequences of circulation and ventilation variability across tectonic, glacial-interglacial, millennial, and modern time scales. We invite contributions that apply a wide range of tools, including stable isotopes, trace elements, radiocarbon, Ɛ_Nd, Pa/Th, and emerging tracers, as well as numerical models. Studies exploring the feedback between circulation and other components of the Earth system, including abrupt climate change, tipping points, and elemental cycling, are particularly welcome. By bringing together geochemical, proxy, and modeling approaches, this session aims to advance dialogue across communities, highlight methodological advancements, and identify key uncertainties for future research. We encourage submissions from all career stages and from all ocean regions, with an emphasis on cross-basin comparisons and global linkages.

Glaciers and ice sheets influence Earth’s dynamic climate system over a wide range of time scales from 10¹ to 10⁹ years. Terrestrial ice is intimately coupled to ocean circulation, sea level, weathering regimes, and atmospheric CO₂, making it an important influence on geochemical, biological, and climate systems. Ice in polar and high-altitude regions is especially sensitive to changes driven by climate forcings. However, unraveling cryospheric and polar climate history and the associated Earth System interactions requires specialized techniques, most effective when set within a multi-proxy interpretive framework. This session aims to bring together scientists using a wide range of existing and novel isotopic, geochemical, and minerogenic/physical proxies to decipher cryosphere and polar climate history. We we welcome studies of ice cores from polar, temperate, and tropical regions and studies designed to understand climate records preserved in terrestrial and aqueous sediments and in more distal marine sediment archives. We invite research that uses a variety of analytical tools including geochronology (¹⁴C, cosmogenic and radiogenic nuclides, luminescence, long-lived radionuclides, amino acid racemization), geochemistry (major and trace elements, organic tracers), traditional and non-traditional stable isotopes, and physical/mineralogical proxies. We encourage contributions related to the development, refinement, and calibration of proxies, abstracts presenting modeling results and integrated approaches to elucidate the roles that polar and sub-polar regions have played in Earth’s climate system, from the Precambrian to the present. Our goal is to catalyze conversations between scientists using different techniques to understand the history of ice and thus Earth's climate over time and space.

The geochemistry community is advancing federated infrastructures that mirror successful models in other sciences. Initiatives such as AuScope EarthBank (Australia), EPOS and EXCITE (Europe), and NASA’s Astromaterials Data System (AstroMat) connect researchers, samples, laboratory networks, analytical workflows, and repositories into open, accessible systems. Global alliances like IEDA2 (integrating EarthChem, PetDB, SESAR2, and LEPR/traceDs), along with community resources such as GeoRoc and Mindat, demonstrate the benefits of coordinated international approaches.

Persistent identifiers—ORCID for researchers, IGSN for samples, PIDINST for instruments, and DOIs for datasets—underpin these systems and ensure transparency, reproducibility, and credit. Initiatives such as OneGeochemistry promote global FAIR standards, while CoreTrustSeal and World Data System certifications ensure repository reliability and sustainability.

Emerging schema for experimental and natural samples now link chemical and textural data through advanced microanalytical methods (SEM, TEM, EMP, LA-ICP-MS, SIMS, micro-CT) that quantify elemental and isotopic compositions at sub-micron scales. The fusion of spatial imaging and geochemical data is generating quantitative archives of natural and experimental materials that enable fully contextual interpretations.

Software tools—from laboratory management and data reduction to co-registration and visualization—are critical enablers. A notable example is EarthBank’s collaboration with the GPlates group, integrating geochemical datasets with plate reconstructions through deep time.

This session invites contributions that highlight:
• End-to-end sample-to-data workflows
• Persistent identifiers for FAIR data
• Integration of digital platforms with physical collections
• Case studies linking open infrastructures to societal outcomes

The 21st century faces urgent challenges such as climate change, resource depletion, and biodiversity loss, necessitating collaboration among industry, governments, and academia. This session will explore the critical role of geochemistry in facilitating sustainable energy transitions through innovative partnerships that link research with practical applications. We invite contributions that showcase successful collaborations in the energy, food, water, and environment nexus, highlighting how these efforts accelerate innovation and develop skilled personnel for both scientific and industrial fields. We welcome studies utilizing advanced techniques to demonstrate how collaborative frameworks provide effective solutions for resource management and environmental protection. By integrating natural resource use and climate solutions, geochemistry-driven partnerships ensure that scientific insights inform policy and technology decisions. Aligned with Goldschmidt's mission to advance geochemistry for societal benefit, this session aims to inspire strategies for a sustainable future and net-zero goals by 2050.

Geochemists and geoscientists use their scientific background to find solutions to global challenges. However, effectively sharing research with the public requires communication skills which are often not a focus during geological training. As a result, scientists may struggle to clearly explain their work to varied audiences, such as the general public, schools, media, policymakers, and stakeholders. Accessible science communication increases social understanding of research and promotes social engagement with geoscience. Presenting geoscience in various formats helps reach public and interdisciplinary audiences, encouraging more students to study geoscience and expanding the range of role models. This session seeks contributions on communicating science to diverse public groups, and communities outside traditional classrooms.

Geochemistry plays an increasingly vital role in the future of geoscience education by

integrating into curricula key concepts that address some of the most pressing societal issues. The future role of geochemistry in this context is shaped by the need to train the next generation of scientists in understanding geochemical cycles in a changing climate, and applying geochemical principles to develop solutions to such challenges as clean energy production, water resource management, carbon squestration and critical mineral discovery and extraction.  Geochemistry also has an important future role in geoscience education by contributing to an informed citizenry, whose ability to judge fact from falsehood will be essential to shaping public policy and the future of society.  Challenges exist to delivering geochemical concepts in ways that appeal to the current generation of students, to ensuring the quality of the content provided, and to making access to this knowledge equitable and inclusive.  This session will bring together the community of geochemical educators to present and discuss experiences and best practices in delivering geochemical knowledge with a goal to not only train the next generation of geoscientists, but to ensure an informed public.

More than ever, we need all hands-on-deck to meet the challenges we face in forging scientific excellence.  Yet some scientists, some of our best, remain barriered from our collective endeavors.  Although we have come far in identifying and creating lists of barriers through workshops and meetings, their elimination remains a largely unmet challenge.  Instead, much of today’s political landscape encourages marginalization.  On the other hand, scientific conferences have made monumental strides in bringing these issues to our attention by launching EDI-specific sessions and sponsoring EDI events within conferences.  But what more can be done to effectively and efficiently remove barriers?  One of our most powerful tools lies idle for reasons as diverse as shame or fear of retribution: personal experience.  Using personal experience as evidence to define the barriers, to reflect on the efforts made by adverse individuals to reinforce those barriers, and to tell stories of compassionate individuals who reach out to lift the marginalized up.  The raw honesty of this approach is underutilized.  A final key is held by the conference venue.  EDI sessions should be placed at mainstream times and in high visibility places sending the clear signal that they are integral to the conference and not a peripheral activity.