Natural hydrogen (H₂) produced by deep mantle and/or crustal processes has emerged as a promising source of carbon-free energy. Most current exploration methods rely on soil-gas sampling at one meter depth, where soil biological activity largely interact with H₂ through both biological production and, predominantly, biological consumption. Assessing the magnitude of microbial consumption and its drivers is therefore crucial in the context of natural hydrogen exploration.  In this study we developed a novel microcosm assay to discriminate the potential kinetics of aerobic H₂ consumption, anaerobic H₂ consumption and anaerobic H₂ production in soils. In parallel, we characterized soil physical, chemical, and biological properties (granulometry, pH, redox state, soil respiration, and enzymatic activities) to identify the factors controlling biological H₂ consumption and production. Experiments were conducted on soil sampled at 1 m depth in three sites exhibiting high soil H₂ concentrations near the North Pyrenean Fault Thrust in the southwest of France. We found that net H₂ production was consistently negligible confirming that biological H₂ and accumulation in soil is unlikely under most conditions. However, we found that H₂ consumption can reached up to 0.3 mmol g^-1 d^-1, indicating that microbial activity has the potential to deplete accumulated H₂ soil within seconds under optimal lab conditions. Three main metabolic pathways were identified for H₂ consumption: aerobic H₂ oxidation, anaerobic acetogenesis and denitrification. H₂ consumption rates were correlated with soil H₂ concentration within a site, suggesting that H₂ consumption directly influences our soil gas measurements. Our results demonstrate that biological consumption may be one of the major drivers of near-surface H₂ concentration and call for additional data to constrain true consumption kinetics across depths and sites.

How to cite: Hoareau, G., Manon, R., Ranchou-Peyruse, A., Guignard, M., C. Gaucher, E., Portier, E., and Rigollet, C.: Microbial masking of deep hydrogen signals in soil-gas measurements , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21676, https://doi.org/10.5194/egusphere-egu26-21676, 2026.

In central Italy, the Apennine fold-and-thrust belt constitutes the boundary between the peri-Tyrrhenian extensional area and the Adriatic compressional-foredeep domain. The different tectonic settings of the two sides of the Apennine promote different geochemical features of the circulating fluids. While the western side  is affected by thermal anomalies, geothermal areas and CO₂ degassing sites, in the easternmost side, the presence of foredeep basins promote the presence of hydrocarbon reservoirs, mud volcanoes, and highly salty mineral waters. An extensive database of chemical-isotopic compositions of groundwater across the central Apennine has been recently compiled in the framework of the EMOTION INGV project which was devoted to the geochemical characterisation of geothermal manifestations in central-northern Italy. About 1000 groundwater analyses were retrieved from the available scientific literature and other data sources. Starting from these data, basing on thermal anomalies and other relevant geochemical-isotopic indicators, ~40 thermal/mineral springs and wells were selected and sampled for a wide-spectrum geochemical analyses including major ions, trace elements, dissolved gases and stable isotopes (H2O, C and He). The thermo-mineral waters of the western sector are generally slightly saline (TDS 1-9 g/L), with temperatures from 15 to 30°C, compositions spanning from Ca(Mg)-HCO3-SO₄ to Na-Cl and affected by the input of deeply derived CO₂. In addition to thermal waters, a slight temperature anomaly of large flow rate springs reveals geothermal heating of the waters corresponding to relevant heat flux. Moving from the “axial” to the easternmost sector, mineral waters show chemical compositions from Ca-SO₄ to Na-Cl, the latter of which reaches very high salinities (TDS up to 183 g/L) and Br^- and I^- relevant contents. In these sectors, mineral waters don’t show significant thermal anomalies and show low to null input of deeply derived CO_2, while showing a relative enrichment in dissolved CH₄. The only exceptions are Triponzo and Acquasanta Terme systems with temperature of ~30 °C and higher CO₂ contents. In this regional trends, local peculiarities are under further investigation. The produced dataset is also valuable for investigating natural resources. For instance, Li occurs at highly variable concentrations (0.01–3 mg/L) but remains of negligible economic significance, with no appreciable differences between the western and eastern sectors. In contrast, other elements of potential interest, such as B, Br, Sr, and Mn, are enriched in the high-salinity waters of the eastern sector, locally attaining potentially useful concentrations.

How to cite: Cardellini, C., Tieri, M., Taussi, M., Cinti, D., Chemeri, L., Procesi, M., Frondini, F., Chiodini, G., Caliro, S., Biagi, R., Zorzi, F., Brusca, L., and Longo, M.: West-East transect of fluids geochemistry across the Umbria-Marche Apennine (Italy): from thermal waters to highly saline fluids, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14099, https://doi.org/10.5194/egusphere-egu26-14099, 2026.

The sedimentary succession of the Laghi Gemelli Group (? Late Carboniferous-Early Permian) outcrops in the northern-central Southern Alpine domain (North Italy, Lombardy) and is composed of volcaniclastic, siliciclastic and subordinate carbonate sediments. The succession was deposited within a fault-bounded basin (Orobic Basin) formed under extensional-transtensional tectonics in the post-Variscan scenario. The stratigraphic succession that build up the Laghi Gemelli Group non-conformably overlies the Variscan Metamorphic Basement and consists of three lithostratigraphic units recording different basin filling phases: 1) alluvial systems dismantling metamorphic uplands (Conglomerato Basale), 2) caldera-centered acidic volcanic systems (Cabianca Volcanite Fm.), and 3) endorheic alluvial systems dismantling metamorphic and volcanic uplands (Pizzo del Diavolo Fm.). A prominent angular unconformity marks the top of the Laghi Gemelli Group, at whose top sits the? Middle-Late Permian Verrucano Lombardo alluvial system.

Excellent outcrop exposures in central Bergamasque Alps (Valgoglio, BG) have progressively fostered a substantial advancement in the understanding of the Lower Permian stratigraphy. However, their geochemical composition and variability – major and trace elements – have largely remained unexplored. Sediment chemistry can contribute to the identification of distinctive geochemical markers that can be employed for basin-scale correlations, a valuable approach in settings characterized by units with pronounced thickness and facies variations.

For the first time, 73 rock samples collected in the central sector of the Orobic Basin from outcrops of the Laghi Gemelli Group and lowermost Verrucano Lombardo have been analyzed at the University of Milan by using the LA-ICP-MS technique. Prior to the analysis, Pressed Powder Pellets (PPPs) were prepared. Although the data analysis didn’t reveal clear significant geochemical trends in both major and trace elements, several local changes are noteworthy. Where preserved below the unconformity with the Verrucano Lombardo, the upper part of the Pizzo del Diavolo Formation, displays an averagely low Na content and substantial increases in K, Li and Cs. No significant geochemical trend or variation has been detected across the unconformity into Verrucano Lombardo sediments. Future investigations may assess whether similar chemofacies occurs in other sectors of the Orobic Basin at a comparable stratigraphic position. Geochemical analysis has also revealed localized anomalies involving a narrow spectrum of elements. Four main patterns were identified: a) high U, Pb, Sb and Cu in altered tuffstones from the top of the Cabianca Volcanite; b) high Zn, Pb and Cd in lacustrine sediments of the lower Pizzo del Diavolo Formation; c) high B in volcaniclastics and mud-heterolithic deposits (Cabianca Volcanite and Pizzo del Diavolo Formation); d) As enrichment accompanied by increased Mo, In and Sb in mudstone facies of the lower Pizzo del Diavolo Formation.

Starting from these new geochemical analyses, future works can peer into the processes that led to such an anomalous concentration in volcano-sedimentary deposits that, except for uranium, have been poorly investigated in the past. Furthermore, broader sampling will reveal how and why some of these anomalies spread into the basin.

How to cite: Reguzzi, S., Chesi, C., Re, S., Moschetti, L., and Tiepolo, M.: Unveiling the Geochemical Signature of the Early Permian Orobic Basin (Laghi Gemelli Group; N Italy), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2957, https://doi.org/10.5194/egusphere-egu26-2957, 2026.

The aviation industry is facing increasing pressure to reduce greenhouse gas emissions, accelerating the development of sustainable aviation fuel (SAF) as an alternative to fossil-based jet fuels. Conventional aviation fuels rely on finite fossil resources and are associated with long-term resource depletion and environmental burdens, whereas SAF has attracted growing attention as a viable option for mitigating emissions from a carbon-cycle perspective. Securing sustainable and reliable feedstocks therefore remains a key challenge for large-scale SAF deployment.

Microbial oils have emerged as promising SAF feedstocks due to their high productivity, ability to utilize diverse substrates, and potential for scalable cultivation. In this context, the exploration of novel feedstocks based on microbial biodiversity is gaining increasing importance, particularly for diversifying resource bases and improving feedstock resilience.

In this study, we screened and comparatively evaluated the oil production potential of microbial strains derived from Korean biological resources. A diverse set of microorganisms isolated from various natural environments in Korea was examined, including filamentous fungi (Mortierella sp., Umbelopsis sp., and Mucor sp.) and oleaginous yeasts (Yarrowia lipolytica and Rhodotorula sp.). All strains were cultivated under identical conditions, and their growth characteristics and intracellular lipid accumulation were systematically assessed. Several native strains exhibiting high microbial oil production capacity were successfully identified, underscoring the potential of Korean microbial biodiversity as a sustainable resource for energy applications.

Taken together, these results highlight microbial oils derived from indigenous microbial resources as viable alternative feedstocks for SAF production, with the potential to reduce dependence on fossil fuels and associated greenhouse gas emissions in the aviation sector. Beyond energy applications, the microbial oil production strategies presented here may also be extended to future uses in food and feed systems, providing foundational insights for sustainable energy transitions and the development of a circular bioeconomy.

Following are results of a study on the "Convergence and Open Sharing System "Project, supported by the Ministry of Education and National Research Foundation of Korea

How to cite: Park, S., Lee, D., Kim, Y., and Lee*, S.-M.: Lipid Profiling of Indigenous Korean Microbial Biodiversity for the Discovery of High-Potential Strains for Sustainable Aviation Fuel(SAF) Production, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15732, https://doi.org/10.5194/egusphere-egu26-15732, 2026.

Enrichment of coalbed methane is fundamentally governed by the formation and distribution of coal seams. In continental fault-depression basins, the mechanisms controlling peat accumulation are more complex than those in stable basins, extending beyond traditional sea-level control models. This study examines the synergistic control of provenance, climate, tectonics, and sedimentation on coal accumulation in such settings, focusing on Member 2 of the Lower Cretaceous Nantun Formation (K₁n²) in the Huhehu Depression, Hailar Basin—a typical continental fault-depression basin and its major source rock interval.By integrating multiple analytical techniques, including organic geochemistry (e.g., biomarkers, carbon isotopes), elemental geochemistry (major, trace, and rare earth elements), petrographic analysis, and seismic-log based sedimentary facies interpretation, this research systematically reconstructs the paleoenvironment during peat accumulation, delineates the spatial distribution of coal seams in detail, and quantitatively to semi-quantitatively evaluates the contributions of various controlling factors.
Key findings are as follows:
(1) Paleoenvironmental Reconstruction and Provenance Characteristics: Comprehensive geochemical indicators reveal that during the peat-forming period of K₁n², the study area experienced warm and humid paleoclimatic conditions with a freshwater environment. The provenance was dominated by intermediate-acidic igneous rocks, exhibiting a weakly neutral to acidic geochemical signature. This combination effectively suppressed large-scale terrigenous clastic input, providing a critical geochemical foundation for the development of low-ash, high-organic-content coal.
(2) Sedimentary-Tectonic Synergistic Control Mechanism and 3D Distribution Patterns: This study clearly identifies the littoral-shallow lacustrine facies as the only dominant peat-accumulating facies within this fault-depression lacustrine setting. Its spatial distribution is strictly constrained by the basin’s "eastern faulting, western overlapping" half-graben structural framework. Coal seams mainly developed in the transitional zone from the eastern steep slope belt to the central depression (sag), where the rate of accommodation space creation remained in long-term balance with the rate of peat accumulation. Seismic attribute analysis and isopach mapping clearly demonstrate an asymmetric distribution of cumulative coal seam thickness—thicker in the east and thinner in the west—trending along the fault zone and thickening significantly toward the east (downthrown block), with thicknesses ranging from 30.84 to 151.24 meters. This distribution forms the material basis for coalbed methane enrichment.
Based on these findings, this study innovatively establishes a comprehensive sedimentary model applicable to continental fault-depression basins: "Weakly Neutral-Acidic Provenance Supply – Warm-Humid Freshwater Environment – Littoral-Shallow Lacustrine Facies Dominance – Peat Accumulation in Steep Slope Belt to Depression Zone." This model systematically elucidates the dynamic coupling among provenance characteristics, paleoclimate, syn-sedimentary tectonic activity, and lake-level fluctuations. It represents an important supplement to and advancement of the classical sea-level-controlled coal accumulation paradigm, forming a novel theoretical framework for peat accumulation in continental fault-depression basins.This research deepens the understanding of the intrinsic mechanisms controlling coal measure formation in fault-depression basins.

How to cite: Tang, Y. and Wang, M.: Mechanism of Coal Accumulation in Fault-Depressed Basins and Exploration Insights: A Case Study of Member 2 of the Nantun Formation in the Huhehu Depression, Hailar Basin, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8625, https://doi.org/10.5194/egusphere-egu26-8625, 2026.

In many water catchment areas, degredation processes in aquifers used for water management ensure a reduction in nitrate pollution. The reaction capacity of aquifers is mainly linked to organic carbon compounds and pyrite. The latter is particularly favoured for denitrification. However, pyrite is a finite resource that is depleted by continuous nitrate inputs. In principle, this leads to the advance of reaction fronts in the aquifer and potentially also to increasing concentrations in the managed groundwater. Model calculations are used to illustrate various dispersion mechanisms and the decisive role of pyrite in regard to the amount of nitrate in the groundwater.

How to cite: Hansen, C. and Kühn, M.: Reduced nitrate degradation in groundwater and its consequences – model-based assessment, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22735, https://doi.org/10.5194/egusphere-egu26-22735, 2026.

Pyrite is ubiquitous in the Earth’s crust, redox-sensitive and prone to oxidation. This applies as well to clay rock formations targeted for the final disposal of radioactive waste. Those rocks are tested in experiments in regard to their suitability for the long-term containment of radionuclides (RN). In the laboratory, samples are often handled under atmospheric conditions, whereas the subsurface provides mainly reducing environments. This means that pyrite can potentially oxidise during experimental procedures, which in turn influences the conditions for the migration of redox-sensitive RN. Different modelling approaches exist to account for pyrite oxidation in geochemical simulations of experiments. The most simple form is the assumption of thermodynamic equilibrium. The application of kinetic rate laws is more complex and computationally intensive.

The electrochemical reaction of pyrite oxidation can be separated into the anodic and cathodic reaction part. They are linked to each other through electron transfer taking place at the interface between mineral surface and pore water. The reductant within the anodic reaction is pyrite itself. Oxidants for the cathodic reaction could be oxygen or ferrous iron. In addition, the direct reaction of other reactants with pyrite, such as oxidised RN, is in some cases thermodynamically feasible for experimental conditions with no or low iron and minor oxygen concentrations in the pore water.

Reactive transport simulations of RN migration in clay rock are compared against experimental data sets. RN occur in different oxidation states, if redox-sensitive. Their mobility and subsequent migration length is governed by the ratio between the most stable oxidised and reduced states under environmental conditions. This is controlled by the inherent redox conditions in the core samples as well as imposed by the introduced pore water chemistry. We test three approaches to model the underlying redox reactions coupled to diffusion and sorption. Firstly, pyrite oxidation in thermodynamic equilibrium. Secondly, different well known kinetic reaction rates for pyrite oxidation. Thirdly, reduction of RN triggered via an iron source associated with the clay minerals. Hence, pyrite oxidation is modelled thermodynamically, kinetically and not at all.

How to cite: Kühn, M. and Hennig, T.: Pyrite oxidation impacts radionuclide migration in clay rock - thermodynamically, kinetically or not at all?, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19401, https://doi.org/10.5194/egusphere-egu26-19401, 2026.

Pyrite oxidation in internal lignite mine dumps is the primary source of acidity, sulfate, and iron in flooded open-pit lignite mines. While the associated geochemical reactions have been extensively studied through modeling, field observations, and laboratory experiments, uncertainties remain due to site-specific factors such as the heterogeneous distribution of sediments and pyrite within the dumps. In particular, these heterogeneities complicate predictions of the temporal contaminant release into surrounding aquifers.

This study investigates the development of reaction fronts in an internal mine dump, focusing on how sediment and pyrite distribution, defined by correlation lengths and mineral content, affects reactive transport processes. Geostatistical methods are combined with geochemical modelling to conduct 2D reactive transport simulations that incorporate pyrite oxidation kinetics.

Results show that heterogeneous scenarios reduce tracer breakthrough time by up to 15 % compared to a homogeneous setup. The total tracer outflux varies between 89 % and 139 % of that observed in the homogeneous reference case. Reaction fronts in heterogeneous configurations cover a larger area and extend deeper into the modelling domain than those in the homogeneous scenario. Simulations that exclude reaction kinetics require more computational time, but result in smoother reaction front edges and more detailed redox gradients compared to equilibrium-based approaches.

The findings indicate that preferential flow paths, that arise from structural heterogeneity, can accelerate flow-through times and enhance solute outflux quantities. The effect scales with oxygen availability for pyrite oxidation. However, while higher oxygen concentrations increase peak and average solute concentrations in the dump, the spatial and temporal patterns of outflux are primarily governed by heterogeneity. Accurate prediction of contaminant release from specific mine dumps remains challenging due to the difficulty of characterising internal structures in the field. However, simulating multiple plausible scenarios allows for estimating ranges of outflux timing and magnitude, supporting risk assessment and groundwater management. The impact of 3D heterogeneities on preferential flow path development in similar geochemical systems remains unexplored and should be addressed in future research.

Literature

Schnepper, T., Kühn, M. and Kempka, T. (2025a): Reaction Path Modeling of Water Pollution Implications of Pumped Hydropower Storage in Closed Open-pit Lignite Mines. Mine Water and the Environment, 44, 107-121. DOI: 10.1007/s10230-025-01039-y

Schnepper, T., Kapusta, K., Strugała-Wilczek, A., Roumpos, C., Louloudis, G., Mertiri, E., Pyrgaki, K., Darmosz, J., Orkisz, D., Najgebauer, D., Kowalczyk, D. and Kempka, T. (2025b): Potential hydrochemical impacts of pumped hydropower storage operation in two European coal regions in transition: the Szczerców-Bełchatów mining complex, Poland, and the Kardia Mine, Greece. Environmental Earth Sciences, 84, 9, 247. DOI: 10.1007/s12665-025-12198-0

Schnepper, T., Kühn, M. and Kempka, T. (2025c): Effects of Permeability and Pyrite Distribution Heterogeneity on Pyrite Oxidation in Flooded Lignite Mine Dumps. Water, 17, 21, 3157. DOI: 10.3390/w17213157

How to cite: Schnepper, T., Kühn, M., and Kempka, T.: Pyrite oxidation and its implications for flooding of heterogeneous lignite mine dumps: a reactive transport modelling study , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19159, https://doi.org/10.5194/egusphere-egu26-19159, 2026.

Pyrite is one of the most abundant sulfide minerals in the Earth’s crust and can host a wide range of transition metals. However, due to their higher electron counts and atomic sizes different from that of Fe, these substitutions often destabilize the lattice, and the mechanisms controlling their incorporation remain poorly understood. Here we use ab initio simulations to systematically investigate transition-metal substitution in pyrite, using Au-As coupling as a representative example within a broader set of transition-metal systems. We analyze defect formation energies, lattice distortions, and electronic structures for single and double substitutional configurations. Isolated substitutions are generally thermodynamically unfavorable, whereas joint substitutions are more likely to take place. In particular, anion-site dopants with fewer valence electrons than sulfur, such as arsenic, facilitate the incorporation of large-radius transition metals by promoting locally constrained coordination environments and alleviating lattice strain. Electronic structure analyses show that impurity stability is governed by band filling and Fermi-level positioning. Double substitution enables electronic compensation, eliminates mid-gap states, and lowers defect formation energies across multiple transition-metal systems. These results establish electronic compensation as a fundamental control on transition-metal enrichment in pyrite, with implications for pyrite-hosted ore deposits and trace-metal capture across the pyrite life cycle.

How to cite: Gao, Z.-Y., Qiu, K.-F., and Caracas, R.: Electronic controls on transition-metal incorporation in pyrite: insights from ab initio simulations, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11853, https://doi.org/10.5194/egusphere-egu26-11853, 2026.

At the source of an orogenic gold deposit, Au and As are inferred to be mobilized during prograde metamorphic breakdown of diagenetic pyrite into pyrrhotite. However, the exact timing and mechanisms of Au and trace element release from diagenetic pyrite is still elusive. Here we investigate trace element chemistry (LA-ICP-MS) of sulfides (diagenetic pyrite, metamorphic pyrite and pyrrhotite) and bulk Au contents from middle greenschist to lower amphibolite facies metapelites (Neoproterozoic Mandhali Formation from NW Indian Lesser Himalayas). Our results show that more than 80% of Au and 65% of As are released from diagenetic pyrite during early metamorphic recrystallization in the middle greenschist facies. In the lower amphibolite facies, pyrite has been completely metamorphosed and has already lost 93% Au, 75% As and the bulk of Pb, Sb, Cu, Bi and most other trace elements prior to breakdown into pyrrhotite. Despite late and incomplete pyrite to pyrrhotite transition in the amphibolite facies, Au was also mobilized from the bulk rock (from 9.0 ppb to 1.1 ppb mean bulk Au) indicating: (1) even a partial pyrite to pyrrhotite transition can result in regional Au mobilization, and (2) Au mobilization occurs in a two-step process involving release from diagenetic pyrite into the rock matrix during metamorphic recrystallization followed by later mobilization in metamorphic fluids.

How to cite: Thathrampally, A. L., Chakravarti, R., Laflamme, C., Olin, P., Magnall, J., and Gleeson, S. A.: Two-step gold mobilization in metamorphic terranes: A refined metamorphic model for Orogenic Gold , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22726, https://doi.org/10.5194/egusphere-egu26-22726, 2026.

Pyrite oxidation coupled with rock weathering occurs on the Barton Peninsula and is likely to be accelerated by progressive glacial melting, which exposes more bedrock to weathering. King George Island (KGI), with a surface area of 1250 km², is the largest of the South Shetland Islands (SSI) and is located about 120 km north of the Antarctic Peninsula. The study area, the Barton Peninsula, forms the southwestern part of KGI and is the second-largest ice-free area on the island, with an approximate surface area of 12 km². The Barton Peninsula is predominantly composed of volcanic and plutonic rocks; volcanic rocks make up most of the peninsula and the sampling area, with compositions ranging from basaltic andesite to andesite. In the northern part of the peninsula, strongly weathered paragneiss displays a distinct rusty coloration caused by pyrite oxidation and is enriched within many of the volcanic rocks (Balci and Gunes, 2024). A series of oxidation experiments using pyrite-bearing and non-pyrite-bearing rocks was conducted, and the results were integrated with water geochemistry as well as the mineralogical and elemental compositions of freshwater, sediments, and rocks to evaluate the influence of pyrite oxidation on surface waters of the peninsula. Acid-production potential analyses show that andesitic rocks exposed at the northern tip of the peninsula have the highest values, ranging from 51.25 to 78.1 kg H₂SO₄ per ton of rock. The pH of the experimental media remained acidic even after 240 days of andesite-water interaction. Consistently, the highest releases of Ca (average 1.2 ppm), Mg (1.34 ppm), Mn (0.056 ppm), K (0.074 ppm), and Fe (0.092 ppm) were observed from pyrite-bearing andesitic rocks, whereas the highest releases of P and N were associated with basaltic andesite. Oxidation of andesitic rocks also released elevated concentrations of Zn and Cu. In agreement with the experimental data, freshwaters with low pH (3.7–4.2), high sulfate (46–92 mg/L), and high Fe (0.8–16.5 mg/L) occur at the northern tip of the peninsula. In contrast to neutral waters, these acidic waters exhibit the highest concentrations of cations (e.g., K, Na, Si, and Ca) and anions (e.g., SO₄²⁻). This indicates that pyrite oxidation coupled with enhanced silicate weathering acts as a powerful natural fertilizer on the peninsula and is likely to increasingly regulate microbial and ecosystem productivity in the future as global warming drives progressive glacial melting.

Keywords: Maritime Antarctica, Pyrite, Nutrients, Oxidation,

References:

Balci and Gunes, 2024 Generation and geochemical characteristics of acid rock drainage (ARD) in Barton Peninsula, King George Island (KGI), maritime, Antarctica, Vol.954 Science of The Total Environment.

How to cite: Balci, N., Sonmez, E., Unal Ercan, H., and Demiraran, O.: Pyrite oxidation enhances nutrient release into freshwater on the Barton Peninsula, Maritime Antarctica, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8872, https://doi.org/10.5194/egusphere-egu26-8872, 2026.

Iron and sulfur isotope geochemistry serves as a powerful tool for probing diverse geological processes, spanning igneous, metamorphic, sedimentary, hydrothermal, and biological systems. Pyrite, a ubiquitous iron and sulfur-bearing mineral in various rock types and the predominant sulfide in hydrothermal ore deposits, is a common product throughout hydrothermal mineralization stages. The coupled Fe-S isotopic system in pyrite offers crucial constraints on fluid sources, fluid–rock interaction, and the physicochemical and redox conditions during mineral precipitation.

In contrast to conventional bulk analytical methods, in situ microanalytical techniques—notably laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) and secondary ion mass spectrometry (SIMS, mainly for S isotopes)—permit to investigate Fe and S isotopic variations and fine-scale heterogeneity at high spatial resolution, which is essential for deciphering complex, multistage hydrothermal systems. The broader application of these techniques, however, is currently limited by the lack of matrix-matched reference materials with well-characterized Fe and S isotopic compositions.

Here, we assess a natural pyrite sample (IGGPy-1) for its major-element and Fe–S isotopic homogeneity. Bulk analysis by elemental analyzer–isotope ratio mass spectrometry (EA-IRMS) yields a δ³⁴S_VCDT value of +17.09 ± 0.30‰. Solution-nebulization MC-ICP-MS (SN-MC-ICP-MS) gives δ⁵⁶Fe_IRMM‑014 and δ⁵⁷Fe_IRMM‑014 values of –1.31 ± 0.06‰ and –1.94 ± 0.12‰, respectively. These results position IGGPy-1 as a promising candidate reference material for in situ Fe–S isotopic microanalysis of pyrite.

How to cite: Xie, L., wang, X., Yu, H., Gao, J., Xu, L., Huang, C., Yang, Y., Wu, S., and wang, H.: A Newly Natural Pyrite Reference Material for In Situ S and Fe Isotope Microanalysis, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12796, https://doi.org/10.5194/egusphere-egu26-12796, 2026.