ERE4.8 | The life cycle of pyrite: from formation to dissolution
The life cycle of pyrite: from formation to dissolution
Co-organized by GMPV5/OS3
Convener: Michael Kühn | Co-conveners: Joseph Magnall, Alwina HovingECSECS
| Mon, 15 Apr, 14:00–15:45 (CEST)
Room 0.51
Posters on site
| Attendance Mon, 15 Apr, 16:15–18:00 (CEST) | Display Mon, 15 Apr, 14:00–18:00
Hall X4
Orals |
Mon, 14:00
Mon, 16:15
Pyrite is the most common sulphide in the Earth’s crust and occurs in many different types of rock. Following many decades of research, the morphology, trace element and isotopic composition of pyrite can be used to reconstruct a range of bio- and geological processes across a broad spectrum of scales.
In the oceans, pyrite is the dominant sink for reduced sulphur and is intimately connected to biological pathways of sulphate reduction, meaning the formation and isotopic composition of pyrite can be used to reconstruct the redox architecture of ancient marine environments. As a major gangue mineral phase in hydrothermal ore deposits, the formation and geochemistry of pyrite can be used to investigate and potentially detect ore forming processes. At the other end of the life-cycle, the weathering of pyrite during acid mine drainage and subsurface geological storage is a major environmental concern.
This session will bring together scientists investigating pyrite across a range of physico-chemical conditions in various earth science disciplines e.g. nuclear waste, ore deposits or acid mine drainage. Our aim is to foster intradisciplinary knowledge transfer of experiences between different research areas. We invite contributions presenting geochemical field studies, in-situ and laboratory investigations of rocks and formations as well as numerical simulation studies within the given context.

Orals: Mon, 15 Apr | Room 0.51

Chairpersons: Joseph Magnall, Alwina Hoving, Michael Kühn
On-site presentation
Stefan Peiffer

The formation of pyrite has been extensively studied because of its abundance in many anoxic environments such as marine and river sediments, groundwater aquifers, and peat lands, and hence its importance in both iron and sulfur cycling. It forms over a wide pH interval, ranging from acidic to alkaline. It is generally regarded that sulfide reacting with iron-containing minerals forms metastable iron sulfide minerals before eventually transforming into pyrite in the presence of different sulfur.

In this contribution, I will discuss the importance of sulfidation of ferric (oxy)hydroxides (FeOOH), i.e. the reaction between aqueous sulfide and the surface of FeOOH, to stimulate pyrite formation and compare this process with other pathways and kinetics of pyrite formation described in the literature. Sulfidation of FeOOH initially leads to formation of surface bound FeS-species and its transformation to pyrite is controlled by either the availability of FeOOH or the supply rate of sulfide. These kinetic constraints define the environments were rapid pyrite formation occurs to be suboxic, rich in FeOOH and shaped by cryptic sulfur cycling. Under these conditions, highly reactive pyrite precursor species are forming that also affect trace metal cycling.

How to cite: Peiffer, S.: Controls on recent pyrite formation in aquatic systems and its relevance for environmental processes, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21260,, 2024.

On-site presentation
Martin Kölling, Ilham Bouimetarhan, and Matthias Zabel

During times of low sea-levels in glacials there is evidence of large-scale pyrite oxidation on exposed continental shelves. While this process directly reduces atmospheric oxygen levels, acid drainage generated by this reaction increases the release of CO2 through carbonate buffering within the previously marine shelf sediments. Although this scenario is expected to result in negative feedback, sea-level and atmospheric CO2 levels have co-varied throughout most of the last 800 thousand years (ka) for which direct records of CO2 exist. Only during peak glacial conditions with sea-levels as low as 125 m lower than today, CO2 levels have reached an apparent lower limit around 190 ppm independent of decreasing sea-levels. Here we show that pyrite driven release of CO2 and decline of O2 during six of the last nine glacial-interglacial cycles are focussed in 10 ka to 40 ka-long periods preceding glacial terminations.

Using a sea-level driven model of pyrite weathering in drained continental shelves, we demonstrate that repeated sea-level low-stands force pyrite oxidation to ever greater depths. This occurs whenever the duration of an interglacial is insufficient to restock the shelf pyrite inventory through sulphate reduction in the shelf sediments. During the Quaternary, the decreasing amount of pyrite in the exposed shelf sediments represents a discharging 'acid capacitor' (Kölling et al., 2019). This model was inspired by experience from modelling pyrite weathering in open-pit lignite mine overburden material which may be interpreted as a scaled-down model of glacial continental shelf exposure during sea-level low-stands.

If pyrite oxidation forced CO2 release specifically at low sea-levels was sufficient to amplify the orbitally driven climate forcing and trigger glacial terminations, the absence of CO2 release caused by exposed pyrite rather than an astronomically controlled '100 ka pacing' might have extended the length of glacial-interglacial cycles from one to two or three obliquity cycles. Future ocean drilling specifically aiming to recover long cores on shelves could reveal the existence of a 'pyrite gap' that should exist between surficial young pyritic layers and deeper old pyritic sequences with indications of acid leaching.


Kölling, M., Bouimetarhan, I., Bowles, M.W. et al. Consistent CO2 release by pyrite oxidation on continental shelves prior to glacial terminations. Nat. Geosci. 12, 929–934 (2019).

How to cite: Kölling, M., Bouimetarhan, I., and Zabel, M.: The shelf life of pyrite - effects of pyrite weathering in exposed continental shelves on global CO2 and O2, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21083,, 2024.

On-site presentation
Jordon Hemingway, Cornelia Mertens, and Sarah Paradis

Microbial sulfate reduction (MSR) and subsequent pyrite burial in marine sediments plays a crucial role in Earth’s long-term carbon and oxygen budgets; by reducing sulfate and producing alkalinity, this process effectively increases atmospheric O2 and lowers CO2 levels. Given that MSR exhibits a large and reduction-rate-dependent sulfur-isotope fractionation, changes in pyrite sulfur-isotope compositions (δ34S values) through geologic time have long been interpreted to reflect global signals such as marine sulfate reduction rates, microbial community behavior, and the amount of sulfur buried as pyrite vs. evaporite minerals. However, recent research has demonstrated that marine MSR fractionation likely operates near an equilibrium limit regardless of reduction rate. These studies instead implicate local environmental and sedimentological factors as drivers of pyrite δ34S values. Despite this advancement, the sensitivity of pyrite formation rate and δ34S value to changes in environmental and sedimentological variables—both today and through geologic time—remains unconstrained due to the complex interactions between controlling variables.

To provide mechanistic and quantitative constraints, we developed and applied a non-dimensional diagenetic model that extracts the natural variables governing pyrite formation. Assuming equilibrium MSR isotope fractionation and using only locally measured or globally interpolated boundary values as inputs (i.e., no free parameters), our model accurately predicts all available modern observations (n = 216 cores) with an average root-mean square error of 0.3 wt % for pyrite content and 16.5 ‰ for δ34S. Extrapolating this result, we estimate global pyrite burial flux to be ~1.3 × 1012 mol FeS2 yr−1 with a weighted-average δ34S value of ~-21 ‰ VCDT.This flux is statistically identical to independent estimates of total riverine sulfate input (i.e., pyrite-oxidation and evaporite-dissolution derived), indicating the sulfur cycle currently operates in steady state. However, calculated pyrite burial exceeds pyrite-oxidation derived inputs, suggesting net atmospheric O2 release and CO2 consumption by the sulfur cycle.

Mechanistically, we conclude that pyrite formation rate is highly sensitive to local reactive iron input, whereas δ34S value is primarily controlled by organic carbon reactivity-to-sedimentation rate ratio (termed Da*, a modified Damköhler number) and organic carbon-to-sulfate ratio (termed Γ0). In contrast to previous models, we show that pyrite δ34S is largely insensitive to bioturbation due to counter-balancing impacts on Da* and Γ0. Rather, when combined with a geologic pyrite δ34S record, our interpretation requires an increase in Da* and decrease in Γ0 since the Paleozoic, possibly driven by changing organic matter reactivity and sulfate concentration through geologic time.

How to cite: Hemingway, J., Mertens, C., and Paradis, S.: Quantifying key drivers of marine pyrite content and isotopic composition, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9060,, 2024.

On-site presentation
Jan J. Falkenberg, Manuel Keith, Karsten M. Haase, Reiner Klemd, Martin Kutzschbach, Anna Grosche, Maria Rosa Scicchitano, Harald Strauss, and Jonguk Kim

Seafloor massive sulfides represent modern analogues to ancient volcanogenic massive sulfide deposits, which can be particularly enriched in volatile and precious metals (e.g., Te, Au, Ag, Cu, Bi, Se) in subduction-related systems. However, it remains unclear whether the influx of magmatic volatiles has a systematic control on the metal endowment of submarine hydrothermal mineralization on the plate-tectonic scale. Using a novel microanalytical approach based on the coupling of SIMS δ34S with trace element LA-ICP-MS on a scale of ~25 µm in pyrite from 11 submarine hydrothermal systems, we could demonstrate for the first time that the Te, As, and Sb contents and the ratios of these elements vary systematically with the δ34S composition of hydrothermal pyrite and native S. In contrast to trace element concentrations, Te/As and Te/Sb show a more significant correlation with δ34S in pyrite, indicating that element ratios provide a more robust record of metal sourcing. On this basis, we define a quantitative trace element threshold of high Te/As (>0.004) and Te/Sb (>0.6) ratios in pyrite that can be used to identify the influx of magmatic volatiles to submarine subduction-related hydrothermal systems independent of δ34S isotope measurements. Two-component fluid mixing simulations further suggest that even small amounts (<0.5 to ~5%) of magmatic volatile influx drastically change the Te/As (and Te/Sb) ratio of the modelled fluid, but only slightly modify its δ34S composition. Hence, Te/As and Te/Sb ratios are more sensitive in recording the influx of magmatic volatiles into submarine hydrothermal systems than S isotope systematics, which are typically influenced by seawater-derived S leading to ambiguous δ34S signatures. We conclude that Te/As and Te/Sb systematics in pyrite provide a robust proxy to evaluate the metal sources in submarine hydrothermal systems from the grain to plate-tectonic scale.

How to cite: Falkenberg, J. J., Keith, M., Haase, K. M., Klemd, R., Kutzschbach, M., Grosche, A., Scicchitano, M. R., Strauss, H., and Kim, J.: Pyrite trace element proxies for magmatic volatile influx in submarine subduction-related hydrothermal systems, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15524,, 2024.

On-site presentation
Peter Berger, Joseph Magnall, Michael Kühn, and Sarah Gleeson

It is vital to keep up with the demand for critical minerals during the transition to sustainable energy systems. Doing so requires expanding our knowledge of ore depositional processes. Pyrite is a common gangue mineral in clastic dominated (CD) deposits, which are the highest value Zn deposits. In CD-type deposits, pyrite is often part of the pre-, syn-, and post-ore paragenesis and can therefore provide an important redox buffer and potentially a source of sulfur during ore deposition. The distribution of syn-ore pyrite beyond economic mineralization can also form an important mineralogical halo around CD-type deposits.

In this study we investigate the role of fluid interaction with different types of pyrite on ore formation in the Teena deposit (Australia). The host unit for the Teena deposit is an organic rich, variably pyritic, dolomitic siltstone. We created a series of 2D, reactive transport models using the software X2t (Geochemists Workbench) to investigate the role of pyrite surface area as a major control on ore deposition.

Similar to many CD-type deposits, the main type of pre-ore diagenetic pyrite in the host unit is framboidal, which has a high surface area, whereas syn-ore generations of pyrite tend to be coarser grained. In the models, pyrite surface area was varied from 100 (syn-ore) to 10,000 cm2/g (diagenetic). Organic matter provided a drive for thermochemical sulfate reduction (TSR) in the models, and TSR rates were varied over several orders of magnitude in accordance with laboratory measured values.

As the incoming hydrothermal fluid reacted with the host unit, pyrite and dolomite are dissolved and sphalerite is precipitated. The surface area of pyrite evolved as it dissolved and reprecipitated in the form of a more massive, lower surface area, hydrothermal pyrite.

Models using the higher surface area values for diagenetic pyrite resulted in more compact and higher grade ore deposition. The pyrite at the inlet in this scenario dissolved completely. As the pyrite reprecipitated, it formed more extensive halo ahead of the sphalerite reaction front than in models using the lower hydrothermal surface area. Slower rates of TSR also broadened the pyrite halo and decreased the sphalerite ore grade. Low pyrite surface area coupled with low TSR rates resulted in a disseminated deposit. Based on these results, the paragenetic evolution of pyrite over the course of hydrothermal alteration and the resulting changes in surface area are an important control on ore grade and the extent of halo formation.

How to cite: Berger, P., Magnall, J., Kühn, M., and Gleeson, S.: The role of pyrite surface area and thermochemical sulfate reduction in clastic-dominant Zn Deposits. , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15652,, 2024.

On-site presentation
Marie Bonitz, Theresa Hennig, Anja Schleicher, Christof Kusebauch, David Jaeggi, and Michael Kühn

Argillaceous rock formations provide favourable properties to act as geological barriers for the disposal of high-level radioactive waste. Opalinus Clay is the chosen host rock in Switzerland and is also being considered in Germany. Pyrite is an ubiquitous mineral found in most argillaceous rock formations, and is also present in the Opalinus Clay and its adjacent units. For the long-term integrity of the disposal site, temporally and spatially stable geochemical conditions are essential. Pyrite might be one essential indicator how the sediment formation is influenced by surrounding aquifers. The appearance and composition of pyrite has been used to investigate different geological processes, such as depositional and diagenetic settings, paleoredox conditions and enrichment processes. The geochemical and mineralogical changes in rock formations provide information about processes in the past, and thus enable an assessment for the future. In this context the detailed analysis of pyrite might be a useful tool.

In May 2023, two boreholes were drilled (15 and 25 m deep) in the Mont Terri underground laboratory to investigate the water-bearing members of the Staffelegg Formation (Toarcian-Sinemurian) underlying the Opalinus Clay (Toarcian). The focus was hereby on the transition zones between the permeable and non-permeable rocks to detect alteration reactions and mobilisation processes. In addition to the analysis of the bulk mineralogy and geochemistry, pathways of groundwater and fracture zones have been investigated by analysing thick sections with X-ray and microscopic methods.

Two groundwater paths have been identified in the Staffelegg Formation with fracture zones and their fillings. Calcite and barite are distinguishable and represent two generations, revealing a change of the groundwater composition with supersaturation at different points in time. Therefore, the hydrogeological system experienced at least two events of advective transport. The analysis of pyrite addresses the question to which extent these events have altered and infiltrated the formations.

Pyrite has been formed diagenetically and potentially syngenetically and is present in varying morphologies: μm- to cm-sized euhedral crystals, framboids and nodules. The size and morphology of diagenetic pyrites provide information about the transport processes in the sediment. Euhedral crystals are found in diffusion dominated systems. Accumulations of microcrystals reflect conditions providing an initial nucleation burst, but further crystal growth is limited by restricted supply of Fe and S as it occurs in diffusion-limited regimes with minor advection. Nodules can form in gently advective or stagnant systems with good nutrient supply. The types of pyrite close to fractures and transition zones is used to characterize the predominant transport process at this position.

Diagenetic carbonates and sulphide or sulphate minerals control the concentration of major cations, and redox reactions. Therefore, they provide information about the succession of processes from deposition, to diagenesis, mobilisation and alteration. Their analysis has the potential to assess the long-term integrity of the Opalinus Clay as a host rock and the surrounding formations. The gained understanding of the hydrogeological influence on the geochemical conditions is to be transferred to other potential disposal sites in argillaceous formations.

How to cite: Bonitz, M., Hennig, T., Schleicher, A., Kusebauch, C., Jaeggi, D., and Kühn, M.: What can we learn from pyrite about the hydrogeology of argillaceous formations?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8617,, 2024.

On-site presentation
Markus Breckheimer, Samer Amayri, Dario Ferreira Sanchez, Daniel Grolimund, and Tobias Reich

The safety case for the final disposal of high-level radioactive waste in a deep geological repository involves a thorough understanding of the geochemical interactions of the potentially mobilized waste inventory with components of a proposed multi-barrier concept.

Argillaceous rock is considered as a potential host rock and final barrier to the biosphere. Opalinus Clay (OPA) from the Mont Terri rock laboratory (St-Ursanne, Switzerland) serves as a reference material for a natural clay rock. As a sedimentary rock and porous medium, OPA exhibits characteristic properties such as a low hydraulic conductivity, limiting the transport of solutes to diffusion, as well as structural and compositional heterogeneities in a range of length scales [1].

To address the influence of the potentially reactive microstructure on solute transport, spatially resolved sorption and diffusion studies of Np(V) and Pu(V,VI) with bulk OPA samples were performed, utilizing synchrotron-based microscopic chemical imaging at the microXAS beamline (Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland), simultaneously obtaining chemical information about the OPA microstructure as well as the distribution and transport patterns of Np and Pu [2-5].

In these studies, domains of pyrite, contained in OPA to about 1 wt. % as microstructural, Fe(II)-bearing heterogeneities, were identified exhibiting an enhanced reactivity regarding redox transformation and immobilization of the solute species as reduced, predominantly tetravalent and therefore less mobile species.

Further sorption studies with isolated pyrite heterogeneities, extracted from the OPA matrix as sub-100 µm sized particles, indicate a reactivity depending on the morphology of the heterogeneities, including the crystallite size distribution (framboidal) and cementing phase of these pyrite aggregates.

The results of these studies should add to an enhanced understanding of reactive transport in a natural clay rock in the context of a deep geological repository.



[1] Nagra (2002). Tech. Ber. 02-03. Projekt Opalinuston. Wettingen, Switzerland.

[2] Fröhlich, D.R., Amayri, S., Drebert, J., Grolimund, D., Huth, J., Kaplan, U., Krause, J. and Reich, T. (2012). Speciation of Np(V) uptake by Opalinus Clay using synchrotron microbeam techniques. Anal. Bioanal. Chem. 404: 2151-2162.

[3] Kaplan, U., Amayri, S., Drebert, J., Rossberg, A., Grolimund, D. and Reich, T. (2017). Geochemical interactions of Plutonium with Opalinus Clay studied by spatially resolved synchrotron radiation techniques. Environ. Sci. Technol. 51: 7892-7902.

[4] Börner, P.J.B. (2017). Sorption and diffusion of Neptunium in Opalinus Clay. PhD thesis. Johannes Gutenberg-Universität Mainz, Mainz, Germany.

[5] Kaplan, U., Amayri, S., Drebert, J., Grolimund, D. and Reich, T. (2024). Plutonium mobility and reactivity in a heterogeneous clay rock barrier accented by synchrotron-based microscopic chemical imaging. Sci. Rep., accepted.



Funding from the German Federal Ministry of Education and Research (BMBF) under contract number 02NUK044B, from the Federal Ministry for the Environment, Nature Conservation, Nuclear Safety and Consumer Protection (BMUV) under contract numbers 02E11415A and 02E11860A, and from the European Union’s Horizon 2020 project EURAD (WP FUTuRE), EC Grant agreement no. 847593, is acknowledged.

How to cite: Breckheimer, M., Amayri, S., Ferreira Sanchez, D., Grolimund, D., and Reich, T.: Geochemical interactions of Np and Pu with pyrite heterogeneities in Opalinus Clay in the context of deep geological repositories, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21650,, 2024.

On-site presentation
Julien Poot, Alexandre Felten, Julien L. Colaux, Rachel Gouttebaron, Guillaume Lepêcheur, Gaëtan Rochez, and Johan Yans

Pyrite is one of the most common sulfides on Earth and occurs in many Cu, Pb and Zn sulfides (hypogene) ore deposits. By using XPS (X-ray Photoelectron Spectroscopy) surface and depth analyses, we propose a new experimental approach to determine the oxidation rate of pyrite in three exposure/conditions: i) air, ii) water and iii) water drip (Figure 1). Pyrite samples are almost pure and were collected from the Danube–Bouchon quarry (Hautrage, Belgium), in Barremian black clays of the Wealden facies sediments in the Mons Basin. These pyrites are nodules with cubic aggregates on the surface which were used for the different experiments.

The results reveal a maximum oxidation rate of 11.7 ± 1.8 nm day−1 for drip exposure associated with the precipitation of Fe-sulfates or/and oxides depending on the experimental conditions. These data can be extrapolated to the different zones of weathering profiles (gossan, saprolite and cementation zone). The extrapolation shows a maximum rate of 4.3 ± 0.6 m Ma−1, values consistent with those obtained by other methods such as isotope dating of weathering profiles (e.g. [1,2]). The oxidation in natural systems can vary following different factors, such as the nature of the host rock (protore) and the primary mineralogy, the porosity/permeability and fractures, the presence of an oxidizing environment, climate change over time, the action of bacteria as catalysts, …

Figure 1 - Macroscopic evolution of pyrite oxidation over time in the different experiments [3]



[1] De Putter T, Ruffet G, Yans J, Mees F (2015) Ore Geol Rev 71:350–362.

[2] Vasconcelos PM, Conroy M (2003) Geochim Cosmochim Acta 67:2913–2930.

[3] Poot J, Felten A, Colaux JL, Gouttebaron R, Lepêcheur G, Rochez G, Yans J (2024) Environ Earth Sci 83:9.

How to cite: Poot, J., Felten, A., Colaux, J. L., Gouttebaron, R., Lepêcheur, G., Rochez, G., and Yans, J.: Pyrite oxidation rates and timing of weathering in supergene deposits: new insights from XPS approach, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21668,, 2024.


Posters on site: Mon, 15 Apr, 16:15–18:00 | Hall X4

Display time: Mon, 15 Apr 14:00–Mon, 15 Apr 18:00
Chairpersons: Alwina Hoving, Joseph Magnall, Michael Kühn
Daniel Smrzka, Zhiyong Lin, Patrick Monien, Wolfgang Bach, Jörn Peckmann, and Gerhard Bohrmann

Pyrite forms at marine hydrocarbon seeps as the result of the microbial oxidation of methane, organic matter, and crude oil coupled to sulphate reduction. Redox sensitive and nutrient trace elements in pyrite may hold valuable information on present and past seepage events, the evolution of fluid composition, as well as the presence of heavy hydrocarbon compounds from crude oil. This study uses the trace element compositions of pyrite that formed at methane seeps and crude oil-dominated seeps to constrain element mobilities during the sulphate reduction processes, and to which degree specific trace elements are captured by pyrite. Pyrite forming at oil seeps shows high Mn/Fe ratios and high Mo content compared to pyrite from methane seeps. These patterns suggest either more intense or persistent sulphidic conditions, or an intensified manganese (oxy)hydroxide shuttle process at oil seeps. Copper and Zn are enriched in oil seepage-derived pyrite while Ni and V enrichment is less pronounced, suggesting either a selective uptake of specific elements by pyrite, or varying trace element compositions of organic compounds oxidized via microbial reduction.   

How to cite: Smrzka, D., Lin, Z., Monien, P., Bach, W., Peckmann, J., and Bohrmann, G.: Pyrite-based trace element fingerprints for methane and oil seepage, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6083,, 2024.

Shailee Bhattacharya, Michael C. Dix, Shikha Sharma, Albert S. Wylie, and Tom Wagner

In order to meet the technological needs of the energy transition, batteries of all scales, particularly those that power electrical vehicles, have become increasingly important. Lithium-ion batteries are in wide use at present, and continued research to improve them has been a focus of energy engineering. This, in turn, has greatly increased the demand for lithium (Li) as a natural resource. While the primary ores of Li (pegmatite, salar brine, and volcanic-associated clay) are generally well-understood, it would be desirable to identify additional Li sources that could be safely and economically exploited. Using material from previous industrial operations (e.g., mine tailings or drill cuttings) as a source of additional Li would be attractive as it would generate little or no new waste material.

Our study was carried out on 15 Devonian shale samples of varying organic richness from wells drilled in the Appalachian basin (USA). Sequential extraction of the samples was performed to measure Li recovery from targeted rock-forming phases, namely the carbonates, Fe-Mn oxyhydroxides, pyrites, and organic matter. The mineralogy of the post-leaching residue was found to be dominated by silicates and anatase, suggesting the target phases were successfully leached out of the whole rock.

Unsurprisingly, the data shows higher whole-rock Li values are observed in samples with a higher total clay content. The lowest whole-rock Li contents correspond to samples having higher contents of total organic carbon (TOC) and pyrite. Unexpectedly, however, samples with relatively lower Li contents (22 ppm) can liberate up to 54% of the total lithium from pyrite alone. Furthermore, we observe a positive correlation between pyrite content and %Li recovery in the pyrite leachate (r2= 0.732). These initial findings suggest that pyrite in conjunction with organic matter may play a previously unrecognized role in the Li distribution in organic-rich shales. The geochemical processes that might cause Li enrichments associated with pyrite are not well-understood. However, since Li mobility is highly sensitive to small increases in temperature, the very high thermal maturation of the studied shale sequence may have significantly impacted Li remobilization during the smectite-to-illite clay-mineral transformation. The common Li-mineral that can coexist with different phases of FeS is Li2S at temperatures ⩽ 75°C – 135°C. Several reaction mechanisms have been proposed, but there is little known about the rate kinetics and reaction steps involved in Li association with pyrite in shales.

This study suggests the possibility that some Li may be sequestered in pyrite in organic-rich shales. As pyrite is a common mineral in the Appalachian Basin, this has implications for exploiting shale pyrite in the Devonian sequence if the Li proves economically extractable. Drill cuttings from past and current oil and gas operations are a ready material upon which to test the feasibility of this concept.

How to cite: Bhattacharya, S., Dix, M. C., Sharma, S., Wylie, A. S., and Wagner, T.: Potential lithium enrichment in pyrites from organic-rich shales, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-369,, 2024.

Alwina Hoving, Josh Guyat, Thilo Behrends, and Jasper Griffioen

Peatlands in the Netherlands contain high amounts of sulfur (S). Drainage of these peatlands has led to oxidation of the peat, more recently enhanced through extended drought periods from the result of climate change. Oxidation of peat leads to the mobilization of S and elevated sulfate levels in surface waters. High sulfate concentrations are considered a water quality problem and can enhance eutrophication. In this study, the S content and S speciation in Dutch peats were investigated and their relation to paleoenvironment and current land-use.

Peat samples from eight locations in an east-west section, varying over paleoenvironment, peat type, proximity to the River Rhine and the North Sea, and current land‑use were analyzed. Sequential sulfur extraction was performed to fractionate iron-monosulfide, pyrite and organic-bound sulfur. Porewater was analyzed for sulfate, iron and nitrate concentrations to investigate their influence on the S speciation.

The analytical results could be split into 3 groups. The first group consisted of peats of marine paleoenvironment which had the highest total S content. Due to limited availability of iron (Fe), sulfur was predominantly present as organic-S and <10% of S was present as pyrite. Group 2 consisted of peat from fluvial paleoenvironment origin. In these groundwater fed, nutrient rich, minerotrophic fens, pyrite made up a larger portion of total S. In group 3, the peat was influenced by the river ‘Oude Rijn’. This river was polluted with higher sulfate concentrations, relative to rain water, and also carried clay particles rich in ferrous iron. Flooding events brought Fe to the peat-forming system resulting in pyrite formation. The influence of land-use was only visible in the top layers; high concentrations of nitrate in combination with a low pyrite content and elevated sulfate concentrations were likely caused by the input of fertilizer and subsequent denitrification and oxidation of pyrite.

Overall, paleoenvironment was found to be the predominant factor controlling S content and S speciation in Dutch peats in the Western Netherlands. Particularly the presence of pyrite was related to the presence of fen reed peats and dependent on a nearby Fe source during peat formation.

How to cite: Hoving, A., Guyat, J., Behrends, T., and Griffioen, J.: Pyrite in Dutch peat - influence of  paleoenvironment and current land use , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21967,, 2024.

Christof Kusebauch, Joseph Michael Magnall, and Sarah Gleeson

Pyrite is the most abundant sulfide on Earth and can host a large variety of trace elements including Au, Co, Mo, Cu, Pb, As, Se, Te, Bi and Sb. Trace element variations in pyrite have been used to study various processes during ore formation, to reconstruct paleo-seawater composition and to understand hydrothermal systems. Furthermore, element enrichment in pyrite can reach high enough concentrations that pyrite itself becomes an ore mineral and can be mined. For example, the enrichment of Au in As-bearing pyrite can reach up to several thousand ppm in the giant Au deposits of the Carlin trend (Nevada, USA). In this case the coupled partitioning of Au and As is considered to be an ore forming process1. The high variability of trace elements in pyrite makes it potentially a powerful tool for the reconstruction of fluid compositions in hydrothermal settings. Nevertheless, the lack of partition coefficients of trace elements between hydrothermal fluids and coexisting/newly forming pyrite hinders a wider use of pyrite as a fluid proxy. Also, the underlying processes controlling the incorporation into the crystal structure and the interplay of different trace elements during partitioning are not well understood.

Here, we present results of hydrothermal batch experiments at 200°C studying the partitioning of Co, Cu, Pb, Se, Bi, As and Sb between aqueous solutions and newly formed pyrite. We use the replacement of siderite to crystalize euhedral pyrites large enough to be measured by LA-ICPMS for their trace element content2. The initial trace element concentration in the experimental fluid varied from 0.1 to 10 ppm. To study the influence of As in pyrite on the D values, As concentration in the experiments was varied independently, whereas all other tracers had a constant ratio. 

Concentrations of trace elements in hydrothermal pyrite range between 10 ppm and 1200 ppm, and depend strongly on the initial fluid composition. Partition coefficients for Sb and Se are in the range of 20-300. Co, Cu, Pb, Bi have lower but more variable D values ranging from 0.1 up to 50. Almost all studied elements show a high compatibility in the pyrite structure, replacing most likely either S (i.e, Se, Sb) or Fe (i.e., Co, Cu, Bi, Pb) in the crystal lattice. Unlike Au, partitioning of studied trace metals is not coupled to the As concentration of newly formed pyrite. Nevertheless, D values of Co, Cu, Se and Sb from experiments with a high concentration of trace elements (i.e., 10 ppm) decrease compared to D values from experiments done at lower concentrations (i.e. 0.1 and 1 ppm). This behavior indicates either a solubility limit of the particular element in the pyrite structure or results from an over-occupation of the potential crystal sites by other trace elements. The partition data from our experiments will help to unlock the potential to use the pyrite composition as a proxy for hydrothermal fluids.      



1 Kusebauch et al., (2019) SciAdvances; 10.1126/sciadv.aav5891

2 Kusebauch et al., (2018) Chemical Geology; 10.1016/j.chemgeo.2018.09.027

How to cite: Kusebauch, C., Magnall, J. M., and Gleeson, S.: Partitioning of trace elements between hydrothermal fluids and pyrite, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21310,, 2024.

Gil-Jae Yim, Seung-Jun Youm, Hyeop-Jo Han, Seon-Yong Lee, and Jin-Young Lee

The utilization of surrounding rocks is required in human living areas, and these development activities create large cut slopes and generate large amounts of cut rocks as construction materials. If these development areas are strata containing sulfide minerals (pyrite, etc.), contamination may occur, causing environmental pollution problems in the development site and surrounding areas. Several methods have been studied for the preliminary identification of potentially contaminated rocks, including Acid Base Accounting (ABA), Modified ABA procedures, Carbonate Neutralization Potential determinations, Humidity cell tests, Column tests, Batch reactor (Shake flask) tests, and Field tests (Orava, 1997; USEPA and Hardrock Mining, 2003). Studies on rock samples have resulted in most of the samples being classified as Non-Acid Forming (NAF), with some samples containing sulfide minerals (such as pyrite) being classified as Potentially Acid Forming (PAF). It can be expected that future development of these rocky areas may affect the surrounding environment or rock utilization. Therefore, these rock areas are considered to be in need of management. It would be desirable to investigate the occurrence of pollution sources caused by mineral sulfides in advance and take appropriate countermeasures. It is expected to reduce the economic losses that may occur in the future, and it is judged that the pollution problem of the surrounding environment can be further reduced.

How to cite: Yim, G.-J., Youm, S.-J., Han, H.-J., Lee, S.-Y., and Lee, J.-Y.: Evaluating the potential source of contamination from sulfide minerals in major rocks in South Korea, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3754,, 2024.

Jui-Ming Chang, I-Feng Wu, Li-Hung Lin, Aaron Bufe, Pei-Ling Wang, Hsi-Ling Chou, Niels Hovius, and Tung-Chou Hsieh

Microbially mediated pyrite oxidation is considered a crucial element of the global weathering engine. However, observations of bacterial pyrite oxidation in nature remain scarce due to limited field sampling, particularly during typhoon precipitation and discharge events. In this study, we present a time series of water chemistry at three-hour intervals from the Sinwulyu River, southeast Taiwan, across the typhoons Nesat (0-27th hours) and Haitung (30th-60th hours) in 2017. The cumulative precipitation for the two typhoons ranged from 18 to 78 mm and 59 to 227 mm in the catchment, resulting in discharge increases from 6 to 122 c.m.s. and 53 to 1,207 c.m.s. at the catchment's outlet. The Sinwulyu River drains a catchment underlain by metamorphosed passive-margin sediments that are rapidly exhuming. Integrating measurements of major ions, δDH2O, δ18OH2O, δ34SSO4, δ18OSO4, and simulations of discharge, we find dynamic changes in the source of solutes to the stream water across the typhoons. Our findings indicate that all chemical solutes experienced dilution by 30-80% during typhoon discharge. δDH2O and δ18OH2O values were more negative with increasing discharge, suggesting that the discharge is driven by a combination of precipitation and groundwater injection into the river. δ34SSO4 and  δ18OSO4 ranged from -3.9 ‰ to -7.1 ‰ and from -1.9 ‰ to -6.5 ‰, respectively, suggesting that the majority of riverine sulfate is sourced from oxidative weathering of pyrite. In addition to variations of the water chemistry, we also found substantial changes in the concentrations of sulphur-oxidizing bacteria, Thiobacillus and, Sulfuricurvum (anaerobic microorganisms) emerged as the dominant genera during typhoons. The peak concentration of Thiobacillus occurred at the first typhoon at the 27th hour (1.17×107 copies/L), while Sulfuricurvum peaked at the 48th hour during the second typhoon (2 hours before peak discharge) with a concentration of 2.32×108 copies/L, coinciding high ranges of sediment concentrations and representing 241 and 1,570 times the background level before typhoons, respectively. Both peak concentrations were sudden appearances, indicating that some pools of concentrated microorganisms were quickly depleted by typhoon precipitation/discharge. Notably, the highest abundance of Sulfuricurvum coincided with an increase in chemical solutes. As the discharge rose from 714 to 1,092 c.m.s. (45-48th hour), the concentration of sulfuricurvum increased around tenfold, coupled with an 8%, 7%, and 7% increase in the concentrations of SO4-2, Ca+2, and Mg+2, respectively. However, other chemical solutes maintained a similar concentration. These observations suggest the typhoon mobilized a specific reservoir of elevated pyrite oxidation for carbonate weathering under anaerobic conditions. Through discharge simulation, the high concentration of solute and Sulfuricurvum mobilized substantially at hourly precipitation rates of over 20 mm/hr. We propose that an ample amount of precipitation is essential to flush out the previously inaccessible pool with anaerobic bacterial pyrite oxidation and subsequent carbonate weathering in the stream.

How to cite: Chang, J.-M., Wu, I.-F., Lin, L.-H., Bufe, A., Wang, P.-L., Chou, H.-L., Hovius, N., and Hsieh, T.-C.: Microbial Pyrite Oxidation and Chemical Weathering to a Typhoon Precipitation and Discharge Event in Taiwan, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14930,, 2024.

Carsten Hansen and Michael Kühn

The assessment in accordance with the Water Framework Directive and the EU Water Framework Directive continues to show poor chemical status for around one third of groundwater bodies in Germany due to excessive nitrate concentrations. In many regions, this is due to high nitrogen fertiliser intensities that have been applied to agricultural land for decades.

Nitrate input and degradation processes in aquifers are modelled using step-by-step hydrogeochemical continuous stirred tank reactors (CSTR) sequences with PHREEQC. This makes it possible to show how the overall water quality is characterised by the interaction of hydrogeochemical sub-processes such as nitrogen and lime fertilisation, substance releases from grassland ploughing, denitrification via organic carbon (heterotrophic degradation) and most importantly pyrite (lithotrophic degradation) and sulphate reduction, but also nitrate breakthroughs and well clogging.

CSTR models are not discretised spatially or temporally; their focus is on identifying and quantifying the relevant hydrogeochemical reactions. The advantage of this method is much shorter and more manageable calculation times than with fully coupled reactive transport models. They provide the user with a comprehensive hydrogeochemical understanding of nitrate degradation by pyrite oxidation processes in groundwater. In addition to reaction kinetic aspects, this also includes the effects of a loss of nitrate degradation capacity [1]. In the focus is the dissolution of pyrite and its re-precipitation and a reaction front developing into the system [2]. Moreover, concentrations of pyrite dissolution products (iron, sulphate, trace metals) can be understood.

Hydrogeochemical modelling in this sense is initially retrospectively oriented based on measurements and the longest possible time series. However, a hydrogeochemical CSTR sequence has been checked for plausibility and validated with sensitivity and parameter studies can then also be used to forecast water quality [3]. This provides a "tool" with which the effects of anthropogenic interventions in a geosystem can be calculated with regard to the effects on groundwater and raw water quality.


[1] Wilde, S., Hansen, C. & Bergmann, A. Nachlassender Nitratabbau im Grundwasser und deren Folgen – abgestufte modellgestützte Bewertungsansätze. Grundwasser 22, 293–308 (2017).

[2] Kübeck, C., Hansen, C., König, C. et al. Ableitung der Reaktivität von organisch gebundenem Kohlenstoff in redoxzonierten Grundwasserleitern – Hydrogeochemische Modellierung kinetisch angetriebener Reaktionssysteme. Grundwasser 15, 103–112 (2010).

[3] Jesußek, A., Hansen, C. & Wilde, S. Identifikation und Regionalisierung von Nitratabbauprozessen in einem Grundwasserleiter – Möglichkeiten und Nutzen für die Wassergewinnung. Grundwasser 21, 333–344 (2016).

How to cite: Hansen, C. and Kühn, M.: Pyrite and its role in the development of nitrate pollution and raw water quality in water catchment areas, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5822,, 2024.