# Control of organic matter on metal mineralisation in uranium-rich black shale “Kupferschiefer”

H.-M. Schulz, S. Bernard, F. Perssen, J.A. Stammeier

► To cite this version:

H.-M. Schulz, S. Bernard, F. Perssen, J.A. Stammeier. Control of organic matter on metal mineralisation in uranium-rich black shale “Kupferschiefer”. Geochemical Perspectives Letters, 2025, 34, pp.17-22. 10.7185/geochemlet.2508. hal-05267401

HAL Id: hal-05267401

https://hal.science/hal-05267401v1

Submitted on 18 Sep 2025

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
# Control of organic matter on metal mineralisation in uranium-rich black shale "Kupferschiefer"

H.-M. Schulz<fnref n="1" />*, S. Bernard<fnref n="2" />, F. Perssen<fnref n="1" />, J.A. Stammeier<fnref n="1" />

OPEN ACCESS

## Abstract

https://doi.org/10.7185/geochemlet.2508

<figure><img src="image_2.png" /></figure>

The natural formation of economically important metal sulfides in the geological "Kupferschiefer" system in Central Europe (i.e. its mineralisation) results from a complex and poorly understood interplay of various processes involving organic matter (OM). Here, we demonstrate that transport of aqueous fluids rich in metal chlorides was limited by laminated, non-porous, and non-fluorescent solid OM in the TOC- and uranium-rich shale T1 of the Kupferschiefer system. These organic laminae exhibit XANES spectra consistent with irradiated type I kerogen or pyrobitumen and can thus be interpreted as remains of fossilised algal mats. The laminae not only enhanced sealing integrity against metal-rich aqueous fluids, but also acted as reductant for metal chloride. Moreover, retained paraffinic oil clogged pore space and

reduced permeability. Similar to processes in petroleum systems, metal-rich chloride brines migrated into a shale reservoir with calcite porosity which was self sealed by internal, impermeable organic laminae. Our results highlight that the fate and behaviour of OM and its degradation products are key for the understanding of a variety of organic-inorganic interactions as they bridge the gap between different geochemical sinks.

Received 15 November 2024 | Accepted 27 January 2025 | Published 28 February 2025

## Introduction

Organic-inorganic interactions in sedimentary basins are important reaction networks which also controlled how metals precipitated in black shales in the geological past (e.g., Bechtel et al., 2002; Greenwood et al., 2013). The Permian Kupferschiefer ore system, a sediment-hosted stratiform copper deposit in northern Central Europe (Oszczepalski, 1999; Borg et al., 2012), is a natural laboratory to study the control of organic matter (OM) on mineralisation processes, especially the organic-inorganic interactions involved. The ore system is characterised by an elevated content of copper, zinc and lead sulfides, and occurs in lower Permian sandstones/conglomerates S1, the overlying upper Permian OM-rich black shale unit T1 (hereafter "Kupferschiefer"; Fig. S-1a,b), the carbonate Ca1 above (Fig. S-1a), and occasionally the hanging anhydrite A1 (Borg et al., 2012; Oszczepalski and Chmielewski, 2018). The lower Kupferschiefer black shale T1 of the ore system exhibits high total organic carbon (TOC) concentrations ≥20 wt. %. Such a large amount of OM is believed to have played a crucial role in trapping metals, with redox reactions between reducing OM and oxidising fluids leading to ore formation (Püttmann et al., 1991). Yet, the exact processes involved remain to be understood. Here, we compile published mineralogical and inorganic geochemical data of variously mineralised, altered or barren Kupferschiefer sections from a variety of geological settings in Germany (Fig. 1a), and combine them with new analytical results. The new data was obtained using reflection microscopy, scanning electron microscopy (SEM), scanning transmission

X-ray microscopy (STXM), open pyrolysis and thermovaporisation. The results unravel the architecture, type and composition of solid OM, thus clarifying its origin and alteration history. The data shows that OM acted as a physical seal and geochemical trap. Altogether, the Kupferschiefer mineralisation processes share similarities with processes occurring in conventional and unconventional petroleum systems. Similarities also exist with hydrogeochemical redox processes in sedimentary basins when geochemical processes are controlled by OM as reductant. OM reduces soluble U(VI) to U(IV) in uranium roll-fronts, or provides anoxic microenvironments for the reaction of metal chloride to sulfide in black shale-hosted stratiform base metal deposits. Our new findings highlight the critical role of OM in sedimentary ore formation, providing both geochemical reactivity and the physical barrier, underlining the significance of organic-inorganic interactions in other OM-rich systems.

## Kupferschiefer Ore Formation in Brief

A single- or multiple-stage epigenetic hydrothermal formation is generally accepted today (summarised in Borg et al., 2012; Symons et al., 2011). In such a scenario, metals were transported as chloride species by brines (Brown, 1984). Yet the source of the metals remains controversial (Borg et al., 2012; Oszczepalski, 1999), as well as the timing of the ore mineralisation in different regions (Symons et al., 2011; Pašava et al., 2010). Such uncertainties may be due either to alteration and

<footnote n="1">1. GFZ German Research Centre for Geosciences, Department 3: Geochemistry, D-14473 Potsdam, Germany</footnote>

<footnote n="2">2. Muséum National d'Histoire Naturelle, Institut de Minéralogie, Physique des Matériaux et Cosmochimie, CNRS UMR 7590, Sorbonne Université, CNRS, F-75005 Paris, France</footnote>

<footnote>* Corresponding author (email: schulzhm@gfz.de)</footnote>
<figure><img src="image_3.png" /><figcaption>**Figure 1** (a) Geographic map of wells, Eisleben shaft, and Lieth outcrop (black star symbol) in Germany where samples were taken (details in Table S-1). Blue colour indicates today's distribution of the Kupferschiefer T1 (modified after Paul, 2006; Borg et al., 2012). Grey shaded areas indicate mineralised areas (combined for areas >0.2 % Cu, Pb, and Zn; Wedepohl and Rentzsch, 2006). (b) Schematic sketch showing the concept of lateral to vertical metal zonation and fluid migration direction of the epigenetic Kupferschiefer system (modified after Borg et al., 2012). Well locations indicate conceptual position relative to Cu, Pb or Zn mineralisation, or where barren Kupferschiefer occurs. White star symbol with "R" indicates samples taken from Rote Fäule in mines (details in Tables S-1, S-2).</figcaption></figure>

recrystallisation of existing sulfides, or to multistage processes which varied in time and space (Alderton et al., 2016). Recent investigations by Mohammedyasin et al. (2023) demonstrated that early diagenetic carbonate (and feldspar) dissolution (Fig. S-1c) created pathways for the infiltrating metal-rich hydrothermal fluids, pinpointing an epigenetic mineralisation. The Kupferschiefer system also exhibits vertical and lateral zonation of metal sulfides (Fig. 1b). This zonation is essentially linked to the hematite-bearing "Rote Fäule" facies, which is thought to represent a dynamic oxidation front (Borg et al., 2012). Zonation is also visible in OM characteristics. Lower hydrogen indices, higher Tmax values (from Rock Eval pyrolysis), and stronger aromatisation may occur in and close to the Rote Fäule (Püttmann et al., 1991; Bechtel et al., 2001, 2002).

## Materials and Methods

Shale samples were collected from the Kupferschiefer T1 interval in several drill cores from Brandenburg, Saxony Anhalt, and Bavaria. Samples were also obtained from now closed mines in Saxony Anhalt (Eisleben) and an outcrop in Schleswig Holstein (Lieth; Fig. 1a). Sediment samples represent deposition in three basin locations with diverse depositional features: (i) basin centre (Lieth outcrop), (ii) distal (Brandenburg, Saxony Anhalt), and (iii) near the southern basin margin (Bavaria). The Kupferschiefer T1 in the Lieth outcrop is not mineralised and serves for comparison with other organic petrographic results (see Fig. S-2). Detailed information for each sample is available in Tables S-1 and S-2. This includes published results (Mohammedyasin et al., 2023; Poetz et al., 2022; Spieth, 2019) as well as new data about TOC and U content, facies (Cu/Pb/Zn or barren), hydrogen index (HI), and from open pyrolysis (aromaticity and gas of pyrolysate), and thermovaporisation. Full details about the procedures of the geochemical and imaging analyses are available in the Supplementary Information.

## Results

The OM in the investigated samples is mostly type I/II kerogen with various hydrogen index values (HI), whereas samples from Sangerhausen and Eisleben contain type III kerogen (Fig. 2a). Highest HI values were recorded in the Bottendorf well and the two Spremberg wells 115 and 121. These samples may best reflect the original composition and thus lowest alteration (Fig. 2a). Except for some preserved and fluorescing algal bodies in samples with low U content (<50 ppm, and HI > 200 mg HC/gTOC; e.g., Fig. 2b), the particulate OM in the Kupferschiefer mainly occurs as various forms of a non-fluorescent solid which extends along lamination (e.g., Fig. 3a,b; see also Fig. S-3), forms net-like layers (e.g., Fig. 3f) or encases mineral grains (Fig. 3d,e). These bedding-parallel organic layers exclusively occur at the bottom of the Kupferschiefer. Moreover, the layers lack (nano)porosity (see Fig. S-4) which is typical for a thermal maturity from the onset until peak oil formation. Such a maturity corresponds to the Tmax values between 420 and 440 °C (Fig. 2a inset). The reflectance of the solid organic layers falls into two distinct groups (Fig. 2b inset) confirming the presence of type I kerogen (reflectance ≤ 0.3 % Ri) and some other maceral type (reflectance ≥ 1.1 % Ri; cf. Koch, 1997; Oszczepalski, 1999) in areas enriched in U-bearing species (oxides, phosphates, etc.; Kucha, 2021). The Kupferschiefer may contain up to 670 ppm U in the Sangerhausen area (Hammer et al., 1990). Even higher values up to 1.3 wt. % U are observed in the clay-organic matrix and more than 10 wt. % U in thucholite in the Polish Kupferschiefer (Kucha, 2003; thucholite are grains of bitumen polymerised by the radiolytic action of U and Th). Related to the zoning, highest U concentrations are reported from the Cu zone in direct contact to the Rote Fäule front in the Sangerhausen area and SW Poland (Hammer et al., 1990; Bechtel et al., 2002). Within a given location, uranium concentration shows a positive correlation with both the aromaticity and gas content of the pyrolysate, except for wells Allstedt and Bottendorf, which each encompass only two or three samples (Fig. 2c,d). At the same time U concentrations tend to negatively correlate with HI values (Fig. 2b; see also Yang et al., 2020). It is important in this context that transition

<figure><img src="image_4.png" /></figure>
<figure><img src="image_5.png" /><figcaption>**Figure 2** (a) Kerogen typing by plotting hydrogen index HI vs. oxygen index OI. Inset: Hydrogen index HI vs. T<sub>max</sub>. (b) Uranium content (ppm) vs. hydrogen index HI. Inset: Reflectance of laminated pyrobitumen plotted against uranium content. (c) Uranium content (ppm) vs. relative gas content (C1–C5) of pyrolysate. (d) Uranium content (ppm) vs. aromaticity of pyrolysate (%). Aromaticity is the relative content of o-xylene over the sum of o-xylene and n-nonene. Comparative data in (c) and (d) for Cambro-Ordovician Kolm and Alum Shale samples, the Triassic Yanchang Fm. from the Ordos Basin in China, and the Tertiary Mulga Rock in Australia are from Yang *et al.* (2020). Dotted green line shows uranium content variations in various wells in the Spreberg deposit after Spieth (2019) whereas the dotted purple line is for the Sangerhausen Basin after Hammer *et al.* (1990).</figcaption></figure>

metals like Cu, Pb, or Zn, etc., in Kupferschiefer have no effect on the kind and amount of gaseous compounds generated in hydrous pyrolysis experiments (Lewan et al., 2008). At high uranium concentrations in the investigated samples, the hydrocarbon fragments generated during open pyrolysis are characterised by gaseous compounds like methane, ethane, etc., besides some low molecular, aromatic compounds like benzene, toluene or naphthalene (except for sample G018899 from well Allstedt). At low uranium concentrations higher molecular alkanes occur together with their alkenes (Fig. S-5). Such features correspond to the metal and U zonation in the Kupferschiefer when the gaseous, low molecular aromatic signature is characteristic for the Rote Fäule zone, but also occurs in the U-rich Cu zone. Due to mobilisation by the oxic brines which caused the Rote Fäule facies, U concentrations typically increase in the neighbouring Cu zone, and then decline in the Pb and Zn zone (Hammer et al., 1990; Bechtel et al., 2002). The retained hydrocarbons, mainly *n*-alkanes, released from the samples by thermovaporisation reveal a similar trend: higher molecular alkanes dominate whereas this feature is missing at high U concentrations in the Rote Fäule and the Cu zone where aromatic hydrocarbons

dominate (Fig. S-6, again except for sample G018899 in well Allstedt). A qualitative comparison of the data gained by open pyrolysis and thermovaporisation indicates retention of a parafinic oil fraction (Fig. S-7).

The C-XANES spectra of the laminated OM from the Kupferschiefer (Fig. 4) share similarities with those of pyrobitumens (i.e. products of secondary cracking of bitumen), such as the pyrobitumens from the marine Posidonia Shale (Lower Jurassic, northern Germany) and the Mississippian Barnett Shale (Fort Worth Basin, Texas, USA) (Bernard et al., 2012a, b). However, irradiation may modify the structure of immature type I or type III kerogens in such a way that it will produce residues exhibiting similar XANES spectra (Le Guillou et al., 2013), with a rather large peak at 285 eV and a distinctive low slope at 285.8 eV, as is the case here, especially for the organic laminae of the Sangerhausen samples (Fig. 4). Organic laminae from Spreberg, Bottendorf and Sangerhausen may thus be composed of either pyrobitumen or irradiated kerogen (likely type I kerogen in Spreberg and Bottendorf samples and type III kerogen in Sangerhausen samples), the main source of radiation being the high uranium content of the Kupferschiefer.

<figure><img src="image_6.png" /></figure>
<figure><img src="image_7.png" /><figcaption>**Figure 3** (a, b) Organic laminae without ore mineralisation. (a) G019422, ZnS facies, Koenen shaft 2, Nienstedt, depth unknown, well laminated OM layers. (b) G018899, well Allstedt, 946.21 m depth, tightly stacked, well laminated OM layers. (c, d) Organic laminae as reactant for ore mineralisation. (c) G020249, Pb/Zn facies, well Ig-Bottendorf-01-2012, 107.5 m depth; left, fluorescence while UV illumination shows small alginate; right, reflected white light. ZnS precipitation replaces organic laminae. (d) G019422, ZnS facies, Koehnen shaft, Nienstedt, depth unknown. Sphalerite precipitated in dissolved carbonate layers surrounded by laminated OM structures, or replaces reductive OM. (e, f) Organic laminae as seal against upward ore mineralisation. (e) G019422, ZnS facies, Koenen shaft 2, Nienstedt, depth unknown, strong ZnS mineralisation in dissolved carbonate in close association with laminated OM layers as seal. (f) G019421, Cu facies, close to Rote Fäule, Münzer shaft, Sangerhausen, depth unknown. Dense network of organic laminae restricts ore mineralisation.</figcaption></figure>

## Origin of Organic Layers and Implications for Mineralisation

The deposition of the 0.4–1.0 m thick and 257.3 ± 1.6 Ma old Kupferschiefer lasted 10–60 kyr, and took place in a water depth between 200–300 m with a low sedimentation rate of 5 mm kyr⁻¹ (Kopp, 2022). The erosion of soils on the basin margins likely enriched the surface waters with nutrients, leading to periodic algal blooming events (primary productivity; Paul, 2006). However, also methanotrophic microbial mats which formed in anoxic bottom water (as in the Kupferschiefer sea) produced OM laminae (cf. Blumenberg et al., 2012). Given the high U concentrations, these organic layers are likely irradiated type I kerogen, implying that the structure of laminae is depositional and not a result from migration. Such irradiation, responsible for the partial amorphisation of these kerogen laminae, has also been regarded as responsible for a loss of hydrogen (cf. Le Guillou et al., 2013). This process could plausibly explain the increase in δD values towards the U-enriched lower Kupferschiefer T1 (Poetz et al., 2022) and the low HI values despite a rather low maturity, as indicated by reflectance values (Fig. 2b). The rare high reflectance values are interpreted as resulting from strong irradiation of organic layers by U decay. This is particularly evidenced by the positive correlation of reflectance values with high U concentrations that occur in the transitional zone of the Kupferschiefer mineralisation (Bechtel et al., 2002; Oszczepalski et al., 2002), especially at the Sangerhausen and Eisleben sites. In contrast, highly armatised spherical or granular clusters (thucholite) in the Polish Kupferschiefer were interpreted as charcoal fragments (Syczewski et al., 2024).

In conclusion, the combined data reveal that organic layers played a crucial role in the mineralisation processes of the Kupferschiefer system:

(1) The upward flow of the metal-laden brine was hindered by the impermeable T1 black shale unit (Figs. S-1b, S-3). Such impermeable nature is interpreted as being directly related to the structuration of non-porous organic layers. As mineralisation also affected the overlying Ca1 carbonate, sealing by organic laminae was not complete. Permeability caused by dissolved carbonate (and feldspar) still prevailed during mineralisation.

(2) Mineralisation of the Kupferschiefer is similar to processes of unconventional and conventional petroleum systems which store fluids and/or gases. The T1 unit served as both a porous and reactive reservoir for sulfide precipitation, and as a cap rock with organic layers ensuring intra-seal integrity (Fig. 3e,f; see also Fig. S-3). Additionally, kerogen swelling and retention of generated high wax oil (see thermovaporisation data in Figs. S-6, S-7) led to clogging pore space by adsorption, thus co-enhancing sealing integrity due to reduced permeability.

(3) The laminated OM offered reductive interfaces, forcing the precipitation of metal sulfides in direct contact to OM, which partly replaced both minerals and OM (Fig. 3c,d). In summary, the ability of OM to act as a reducing agent has significant hydrogeochemical implications for mineralising systems within sedimentary basins. For example, the zonation of metals and ore minerals in the “Kupferschiefer” system exhibits not only
<figure><img src="image_8.png" /></figure>

**Figure 4** STXM characterisation of the investigated samples at the carbon K-edge showing C-XANES spectra of different pyrobitumens in Kupferschiefer T1. The spectra are compared with pyrobitumen of the Lower Jurassic Posidonia Shale in northern Germany (Bernard *et al.*, 2012a), pyrobitumen in the Mississippian Barnett Shale (Fort Worth Basin, Texas, USA; Bernard *et al.*, 2012b), and with kerogen type I and III as reference and after irradiation (Le Guillou *et al.*, 2013).

significant hydrogeochemical similarities to petroleum systems, but also to uranium roll-front deposits (cf. van Berk and Fu, 2017) where a migrating aqueous phase enriched in soluble U(VI) meets labile OM which reduces the soluble uranium phase so that U(IV) precipitates.

## Acknowledgements

Samples were kindly provided by B. Friedrich (Mansfeld, Germany), M. Göthel (Wünsdorf, Germany), B.-C. Ehling (Halle/Sa., Germany), L. Katzschmann and Sebastian Wagner (Weimar, Germany), K. Poschlod (Augsburg, Germany), A. Ehling (Berlin, Germany), and A. Grube (Hamburg, Germany). We are grateful to K. Hahne, H. Liep, H. Rothe, I. Schäpan, A. Schreiber and R. Wirth from GFZ German Research Centre for Geosciences (Potsdam, Germany) for their technical support. The HERMES beamline (SOLEIL) is supported by the CNRS, the CEA, the Region Ile de France, the Conseil Départemental de l'Essonne and the Region Centre. We thank H. Sanei for advice and input. Finally, we thank M. Blumenberg and an anonymous reviewer for their constructive and helpful feedback, as well as A. Kappler for editorial handling.

Editor: Andreas Kappler

## Additional Information

Supplementary Information accompanies this letter at https://www.geochemicalperspectivesletters.org/article2508.

<figure><img src="image_9.png" /></figure>

© 2025 The Authors. This work is distributed under the Creative Commons Attribution 4.0 License, which permits unrestricted use,

distribution, and reproduction in any medium, provided the original author and source are credited. Additional information is available at http://www.geochemicalperspectivesletters.org/copyright-and-permissions.

Cite this letter as: Schulz, H.-M., Bernard, S., Perssen, F., Stammeier, J.A. (2025) Control of organic matter on metal mineralisation in uranium-rich black shale "Kupferschiefer". *Geochem. Persp. Let.* 34, 17-22. https://doi.org/10.7185/geochemlet.2508

## References

ALDERTON, D.H.M., SELBY, D., KUCHA, H., BLUNDELL, D.J. (2016) A multistage origin for Kupferschiefer mineralization. *Ore Geology Reviews* 79, 535-543. https://doi.org/10.1016/j.oregeorev.2016.05.007
BECHTEL, A., GRATZER, R., PUTTMANN, W., OSZCZEPALSKI, S. (2001) Variable alteration of organic matter in relation to metal zoning at the Rote Fäule front (Lubin-Sieroszowice mining district, SW Poland). *Organic Geochemistry* 32, 377–395. https://doi.org/10.1016/S0146-6380(01)00002-X

BECHTEL, A., GRATZER, R., PUTTMANN, W., OSZCZEPALSKI, S. (2002) Geochemical characteristics across the oxic/anoxic interface (Rote Fäule front) within the Kupferschiefer of the Lubin-Sieroszowice mining district (SW Poland). *Chemical Geology* 185, 9–31. https://doi.org/10.1016/S0009-2541(01)00395-3

BERNARD, S., HORSFIELD, B., SCHULZ, H.-M., WIRTH, R., SCHREIBER, A., SHERWOOD, N. (2012a) Geochemical evolution of organic-rich shales with increasing maturity: A STXM and TEM study of the Posidonia Shale (Lower Toarcian, northern Germany). *Marine and Petroleum Geology* 31, 70–89. https://doi.org/10.1016/j.marpetgeo.2011.05.010

BERNARD, S., WIRTH, R., SCHREIBER, A., SCHULZ, H.-M., HORSFIELD, B. (2012b) Formation of nanoporous pyrobitumen residues during maturation of the Barnett Shale (Fort Worth Basin). *International Journal of Coal Geology* 103, 3–11. https://doi.org/10.1016/j.coal.2012.04.010

BLUMENBERG, M., THIEL, V., RIEGEL, W., KAH, L.C., REITNER, J. (2012) Biomarkers of black shales formed by microbial mats, Late Mesoproterozoic (1.1 Ga) Taoudeni Basin, Mauritania. *Precambrian Research* 196–197, 113–127. https://doi.org/10.1016/j.precamres.2011.11.010

BORG, G., PIESTRYŻNISKI, A., BACHMANN, G.H., PUTTMANN, W., WALTHER, S., FIEDLER, M. (2012) An Overview of the European Kupferschiefer Deposits. In: HEDENQUIST, J.W., HARRIS, M., CAMUS, F. (Eds.) *Geology and Genesis of Major Copper Deposits and Districts of the World: A Tribute to Richard H. Sillitoe*. Society of Economic Geologists, Littleton, Special Publication 16, 455–486. https://doi.org/10.5382/SP.16.18

BROWN, A.C. (1984) Alternative sources of metals for stratiform copper deposits. *Precambrian Research* 25, 61–74. https://doi.org/10.1016/0301-9268(84)90024-X

GREENWOOD, P.F., BROCKS, J.J., GRICE, K., SCHWARK, L., JARAULA, C.M.B., DICK, J.M., EVANS, K.A. (2013) Organic geochemistry and mineralogy. I. Characterisation of organic matter associated with metal deposits. *Ore Geology Reviews* 50, 1–27. https://doi.org/10.1016/j.oregeorev.2012.10.004

HAMMER, J., JUNGE, F., ROSLER, H.J., NIESE, S., GLEISBERG, B., STIEHL, G. (1990) Element and isotope geochemical investigations of the Kupferschiefer in the vicinity of “Rote Fäule”, indicating copper mineralization (Sangerhausen basin, G.D.R.). *Chemical Geology* 85, 345–360. https://doi.org/10.1016/0009-2541(90)90012-V

KOCH, J. (1997) Organic petrographic investigations of the Kupferschiefer in northern Germany. *International Journal of Coal Geology* 33, 301–316. https://doi.org/10.1016/S0166-5162(96)00047-X

KOPP, J.C. (2022) Kupfer-Silber-Lagerstätten im basalen Zechstein (Kupferschiefer und -mergel; Oberes Perm) zwischen Leszczyna (Nordsudetische Mulde, Polen) und Spremberg (Lausitz, Deutschland). *Schriftenreihe der Deutschen Gesellschaft für Geowissenschaften, Deutsche Geologische Gesellschaft - Geologische Vereinigun, Hannover*, 97. ISBN 978-3-510-49291-6

KUCHA, H. (2003) Geology, mineralogy and geochemistry of the Kupferschiefer, Poland. In: KELLY, J.G., ANDREW, C.J., ASHTON, J.H., BOLAND, M.B., EARLS, G., FUS-CIARDI, L., STANLEY, G. (Eds.) *Europe's Major Base Metal Deposits*. Irish Association for Economic Geology, Dublin, 215–238. https://doi.org/10.2113/gsecongeo.102.4.761

KUCHA, H. (2021) New minerals and the first mineral occurrences in the Kupferschiefer (U, REE, HgS, chloride minerals PtAs₂, Pt(Sb,Bi)₂, PtBi₂), Poland, and their genetic meaning. *Mineralogia* 52, 31–42. https://doi.org/10.2478/mipo-2021-0004

LE GUILLOU, C., REMUSAT, L., BERNARD, S., BREARLEY, A.J., LEROUX, H. (2013) Amorphization and D/H fractionation of kerogens during experimental electron irradiation: Comparison with chondritic organic matter. *Icarus* 226, 101–110. https://doi.org/10.1016/j.icarus.2013.05.003

LEWAN, M.D., KOTARBA, M.J., WIĘCLAW, D., PIESTRYŻNISKI, A. (2008) Evaluating transition-metal catalysis in gas generation from the Permian Kupferschiefer by hydrous pyrolysis. *Geochimica et Cosmochimica Acta* 72, 4069–4093. https://doi.org/10.1016/j.gca.2008.06.003

MOHAMMEDYASIN, M.S., MAGNALL, J.M., GLEESON, S.A., SCHULZ, H.-M., SCHLEICHER, A.M., STAMMEIER, J.A., EHLING, B.-C. (2023) Diagenetic History and Timing of Cu and Zn-Pb Sulfide Mineralization in the Permian Kupferschiefer System, Saale Subbasin, Eastern Germany. *Economic Geology* 118, 1467–1494. https://doi.org/10.5382/econgeo.5015

OSZCZEPALSKI, S. (1999) Origin of the Kupferschiefer polymetallic mineralization in Poland. *Mineralium Deposita* 34, 599–613. https://doi.org/10.1007/s00126005022

OSZCZEPALSKI, S., CHMIELEWSKI, A. (2018) Mineralization of the Zechstein Lower Anhydrite in the Fore-Sudetic Monocline. *Biuletyn Państwowego Instytutu Geologicznego* 472, 135–154. https://doi.org/10.5604/01.3001.0012.7116

OSZCZEPALSKI, S., NOWAK, G.J., BECHTEL, A., ZAK, K. (2002) Evidence of oxidation of the Kupferschiefer in the Lubin-Sieroszowice deposit, Poland: implications for Cu-Ag and Au-Pt-Pd mineralisation. *Geological Quarterly* 46, 1–23.

PAŠAVA, J., OSZCZEPALSKI, S., DU, A. (2010) Re–Os age of non-mineralized black shale from the Kupferschiefer, Poland, and implications for metal enrichment. *Mineralium Deposita* 45, 189–199. https://doi.org/10.1007/s00126-009-0269-8

PAUL, J. (2006) The Kupferschiefer: Lithology, stratigraphy, facies and metallogeny of a black-shale. *Zeitschrift der Deutschen Gesellschaft für Geowissenschaften* 157, 57–76. https://doi.org/10.1127/1860-1804/2006/0157-0057

POETZ, S., LIU, Y., MAGNALL, J.M., VIETH-HILLEBRAND, A., YANG, S., GOTHEL, M., GLEESON, S.A., SCHULZ, H.-M. (2022) Signals of low grade organic matter alteration in the Upper Permian Kupferschiefer (Spremberg area, Eastern Germany) – A by-product of copper mineralization? *Organic Geochemistry* 169, 104421. https://doi.org/10.1016/j.orggeochem.2022.10.04421

PUTTMANN, W., FERMONT, W.J.J., SPECZIK, S. (1991) The possible role of organic matter in transport and accumulation of metals exemplified by the Permian Kupferschiefer formation. *Ore Geology Reviews* 6, 563–579. https://doi.org/10.1016/0169-1368(91)90047-B

SPIETH, V. (2019) *Zechstein Kupferschiefer at Spremberg and Related Sites: Hot Hydrothermal Origin of the Polymetallic Cu-Ag-Au Deposit*. Ph.D. thesis, University of Stuttgart, Germany.

SYCZEWSKI, M.D., PANAJEW, P., MARYNOWSKI, L., WALICZEK, M., BORKOWSKI, A., ROHOVEC, J., MATOUŠKOVÁ, Š., SEKUDEWICZ, I., LISZEWSKA, M., JANKIEWICZ, B., MUKHAMED'YAROVA, A.N., SLOWAKIEWICZ, M. (2024) Geochemical implications of uranium-bearing thulite aggregates in the Upper Permian Kupferschiefer shale, Lubin district, Poland. *Mineralium Deposita* 59, 1595–1618. https://doi.org/10.1007/s00126-024-01279-y

SYMONS, D.T.A., KAWASAKI, K., WALTHER, S., BORG, G. (2011) Paleomagnetism of the Cu-Zn-Pb-bearing Kupferschiefer black shale (Upper Permian) at Sangerhausen, Germany. *Mineralium Deposita* 46, 137–152. https://doi.org/10.1007/s00126-010-0319-2

VAN BERK, W., FU, Y. (2017) Redox Roll-Front Mobilization of Geogenic Uranium by Nitrate Input into Aquifers: Risks for Groundwater Resources. *Environmental Science & Technology* 51, 337–345. https://doi.org/10.1021/acs.est.6b01569

WEDEPOHL, K.H., RENTZSCH, J. (2006) The composition of brines in the early diagenetic mineralization of the Permian Kupferschiefer in Germany. *Contributions to Mineralogy and Petrology* 152, 323–333. https://doi.org/10.1007/s00410-006-0105-4

YANG, S., SCHULZ, H.-M., HORSFIELD, B., SCHOVSBO, N.H., GRICE, K., ZHANG, J. (2020) Geological alteration of organic macromolecules by irradiation: Implication for organic matter occurrence on Mars. *Geology* 48, 713–717. https://doi.org/10.1130/G47171.1
# Control of organic matter on metal mineralisation in the uranium-rich black shale “Kupferschiefer”

H.-M. Schulz, S. Bernard, F. Perssen, J.A. Stammeier

## Supplementary Information

The Supplementary Information includes:

* Methodology

* Supplementary Tables S-1 to S-2

* Supplementary Figures S-1 to S-7

* Supplementary Information References

## Methodology

Core samples were cleaned by water, cut, and powdered. TOC content and bulk pyrolysis parameters using a Rock-Eval 6 instrument were determined by Applied Petroleum Technology AS (APT, Oslo).

The concentration and composition of free hydrocarbons present in the Kupferschiefer T1 were determined applying thermovaporisation-gas chromatography whereas the genetic potential was analyzed using open-system pyrolysis-gas chromatography. Analytical details are given in Rippen *et al.* (2013) and Hartwig *et al.* (2010). The calculation and interpretation of parameters followed Horsfield (1989) and Yang *et al.* (2020).

Uranium concentration analyses were conducted at the ElMiE Lab at the German Centre for Geosciences (GFZ). In brief, samples were digested with the 4-acid method (hot aqua regia/HF/HClO4) in Savillex® PFA beakers (Savillex Corp., Eden Prairie, USA) using ultrapure reagents. Full description can be found in Stammeier *et al.* (2023). High-resolution ICP-MS (ELEMENT XR, Thermo Scientific) was used to measure trace element concentrations with an analytical precision typically within 10 %. For analysis samples were doped with 1 µl/l-1 In to correct for sensitivity drift. Acid blanks were subtracted from each measurement, and the procedural blank was negligible compared to sample concentrations.

All petrographic investigations were conducted on polished, thick sections. For organic petrography and reflectance measurements a Leica DM4P microscope with a XBO 75 watt / HBO 100 watt lamp emitting 546 nm monochromatic light and Zeiss Immersol 518 N immersion oil was used. The microscope was equipped with a digital camera Basler scout scA, mono, 1392x 1040. The photo-documentation and the reflectance of the organic layers in polished thick sections was conducted using the Hilgers FOSSIL MOT software. The calibration standard for reflection
measurements was a YAG with ca. 0.9% reflection (Klein+Becker) with integrated optical zero standard. Full details about organic petrography and reflectance measurements are given in Hartwig *et al.* (2010).

Polished thick sections were carbon-coated for backscattered electron microscopy (BSEM) and for selection of foil position to be cut for transmission electron microscope (TEM) imaging.

For BSEM an Ultra Plus field emission scanning electron microscope (Carl Zeiss Microscopy GmbH) was used that was coupled to an electron dispersive spectrometry (EDS) and that allowed semiquantitative compositional analysis (see details in Mohammedyasin *et al.*, 2023).

Transmission electron microscopy of electron transparent foils was performed using a TECNAI F20 XTWIN TEM operated at 200 kV with a field emission gun (FEG) as the electron source. The TEM is equipped with a Gatan Tridiem energy filter, an EDAX Genesis X-ray analyzer and a Fishione high angle annular dark file detector (HAADF) allowing image acquisition in the scanning transmission electron microscopy (STEM) mode. Analytical details are summarized in Wirth (2009) and Bernard *et al.* (2013).

STXM-XANES data of the present were collected using the HERMES STXM beamline operating at the synchrotron SOLEIL (Saint-Aubin, France; Belkhou *et al.*, 2015; Swaraj *et al.*, 2017). Hypercube data (stacks) covering the FIB foils were collected using a spot of 50 nm, with a spectral resolution of 0.1 eV over the carbon (270–340 eV) absorption range. A dwell time of less than 1 ms per pixel was selected to prevent irradiation damage (Wang *et al.*, 2009). Extraction and normalization of spectroscopic data were achieved using the aXis2000 software (ver2.1n) and the QUANTORXS freeware (Le Guillou *et al.*, 2018).
Supplementary Tables

<table><caption>Table S-1 Origin and basic data of Kupferschiefer T1 samples.</caption><thead><tr><th>Well / Shaft*/Outcrop**</th><th>Location</th><th>Sample no.</th><th>Depth (m)</th><th>TOC (wt.%)</th><th>Hydrogen Index HI (mg HC/g TOC)</th><th>Oxygen Index OI (mg CO2/g TOC)</th><th>Tmax (°C)</th><th>Uranium (ppm)</th><th>Mineralisation</th></tr></thead><tbody><tr><td>Spremberg 121</td><td>Southern Brandenburg</td><td>G017734</td><td>1072.91</td><td>8.38</td><td>392</td><td>12</td><td>433</td><td>17</td><td>Cu, Pb</td></tr><tr><td>Spremberg 121</td><td>Southern Brandenburg</td><td>G017735</td><td>1072.99</td><td>4.8</td><td>385</td><td>19</td><td>434</td><td>20</td><td>Cu, Pb</td></tr><tr><td>Spremberg 121</td><td>Southern Brandenburg</td><td>G017736</td><td>1073.06</td><td>7.95</td><td>391</td><td>14</td><td>432</td><td>13</td><td>Cu, Pb</td></tr><tr><td>Spremberg 121</td><td>Southern Brandenburg</td><td>G017737</td><td>1073.19</td><td>10.6</td><td>433</td><td>12</td><td>429</td><td>27</td><td>Cu, Pb</td></tr><tr><td>Spremberg 121</td><td>Southern Brandenburg</td><td>G017738</td><td>1073.24</td><td>17.3</td><td>394</td><td>10</td><td>427</td><td>43</td><td>Cu, Pb</td></tr><tr><td>Spremberg 121</td><td>Southern Brandenburg</td><td>G017739</td><td>1073.30</td><td>17.9</td><td>378</td><td>8</td><td>427</td><td>38</td><td>Cu, Pb</td></tr><tr><td>Spremberg 115</td><td>Southern Brandenburg</td><td>G017749</td><td>1318.48</td><td>3.9</td><td>376</td><td>18</td><td>435</td><td>12</td><td>Pb, Zn (Cu)</td></tr><tr><td>Spremberg 115</td><td>Southern Brandenburg</td><td>G017750</td><td>1318.54</td><td>3.53</td><td>355</td><td>24</td><td>436</td><td>10</td><td>Pb, Zn (Cu)</td></tr><tr><td>Spremberg 115</td><td>Southern Brandenburg</td><td>G017751</td><td>1318.74</td><td>6.3</td><td>466</td><td>12</td><td>434</td><td>26</td><td>Pb, Zn (Cu)</td></tr><tr><td>Spremberg 115</td><td>Southern Brandenburg</td><td>G017752</td><td>1318.85</td><td>1.74</td><td>261</td><td>40</td><td>438</td><td>n.d.</td><td>Pb, Zn (Cu)</td></tr><tr><td>Spremberg 115</td><td>Southern Brandenburg</td><td>G017753</td><td>1318.87</td><td>11.6</td><td>376</td><td>10</td><td>425</td><td>41</td><td>Pb, Zn (Cu)</td></tr><tr><td>Sangerhausen 102/80</td><td>Saale Basin</td><td>G018873</td><td>430.05</td><td>1.05</td><td>39</td><td>115</td><td>441</td><td>12</td><td>Cu</td></tr><tr><td>Sangerhausen 102/80</td><td>Saale Basin</td><td>G018874</td><td>430.08</td><td>1.15</td><td>53</td><td>73</td><td>440</td><td>14</td><td>Cu</td></tr><tr><td>Sangerhausen 102/80</td><td>Saale Basin</td><td>G018875</td><td>430.16</td><td>4.92</td><td>60</td><td>39</td><td>439</td><td>30</td><td>Cu</td></tr><tr><td>Sangerhausen 102/80</td><td>Saale Basin</td><td>G018876</td><td>430.19</td><td>3.76</td><td>41</td><td>53</td><td>439</td><td>32</td><td>Cu</td></tr><tr><td>Sangerhausen 102/80</td><td>Saale Basin</td><td>G018877</td><td>430.23</td><td>3.89</td><td>25</td><td>41</td><td>438</td><td>38</td><td>Cu</td></tr><tr><td>Sangerhausen 102/80</td><td>Saale Basin</td><td>G018878</td><td>430.28</td><td>10.3</td><td>14</td><td>25</td><td>443</td><td>91</td><td>Cu</td></tr><tr><td>Sangerhausen 102/80</td><td>Saale Basin</td><td>G018879</td><td>430.33</td><td>8.28</td><td>11</td><td>8</td><td>452</td><td>94</td><td>Cu</td></tr><tr><td>Allstedt 11/86</td><td>Saale Basin</td><td>G018897</td><td>946.12</td><td>4.7</td><td>171</td><td>24</td><td>435</td><td>298</td><td>Cu</td></tr><tr><td>Allstedt 11/86</td><td>Saale Basin</td><td>G018898</td><td>946.17</td><td>14.3</td><td>234</td><td>15</td><td>429</td><td>204</td><td>Cu</td></tr><tr><td>Allstedt 11/86</td><td>Saale Basin</td><td>G018899</td><td>946.21</td><td>20.3</td><td>56</td><td>22</td><td>434</td><td>n.d.</td><td>Cu</td></tr><tr><td>Ig Wallendorf/Luppe 6/84</td><td>Saale Basin</td><td>G018907</td><td>359.4</td><td>3.93</td><td>228</td><td>24</td><td>441</td><td>12</td><td>Cu, Pb, Zn</td></tr><tr><td>Ig Wallendorf/Luppe 6/84</td><td>Saale Basin</td><td>G018908</td><td>359.42</td><td>2.78</td><td>227</td><td>54</td><td>439</td><td>30</td><td>Cu, Pb, Zn</td></tr><tr><td>Ig Wallendorf/Luppe 6/84</td><td>Saale Basin</td><td>G018909</td><td>359.45</td><td>5.14</td><td>240</td><td>19</td><td>436</td><td>29</td><td>Cu, Pb, Zn</td></tr><tr><td>Ig Wallendorf/Luppe 6/84</td><td>Saale Basin</td><td>G018910</td><td>359.5</td><td>3.37</td><td>289</td><td>12</td><td>434</td><td>23</td><td>Cu, Pb, Zn</td></tr><tr><td>Ig Wallendorf/Luppe 6/84</td><td>Saale Basin</td><td>G018911</td><td>359.55</td><td>14.8</td><td>306</td><td>7</td><td>436</td><td>39</td><td>Cu, Pb, Zn</td></tr><tr><td>Ig Wallendorf/Luppe 6/84</td><td>Saale Basin</td><td>G018912</td><td>359.6</td><td>19.4</td><td>263</td><td>9</td><td>431</td><td>55</td><td>Cu, Pb, Zn</td></tr><tr><td>Ig Bottendorf -01-2021</td><td>Thuringian Basin</td><td>G020229/47</td><td>107.75</td><td>13.4</td><td>299</td><td>2</td><td>433</td><td>47</td><td>Pb, Zn</td></tr><tr><td>Ig Bottendorf -01-2021</td><td>Thuringian Basin</td><td>G020230/48</td><td>107.72</td><td>21.5</td><td>362</td><td>2</td><td>433</td><td>75</td><td>Pb, Zn</td></tr><tr><td>Neuenbuch</td><td>Lower Franconia</td><td>G019526</td><td>383.49</td><td>0.13</td><td>38</td><td>754</td><td>310</td><td>n.d.</td><td>No</td></tr><tr><td>Zeitlofs</td><td>Lower Franconia</td><td>G019527</td><td>533.60</td><td>1.01</td><td>16</td><td>80</td><td>559</td><td>n.d.</td><td>No</td></tr><tr><td>Kruemmebuch</td><td>Lower Franconia</td><td>G019528</td><td>463.30</td><td>6.66</td><td>37</td><td>17</td><td>441</td><td>n.d.</td><td>No</td></tr><tr><td>*Ernst-Thälmann</td><td>Saale Basin</td><td>G019669</td><td>unknown</td><td>6.60</td><td>15</td><td>31</td><td>431</td><td>119</td><td>Rote Fäule</td></tr><tr><td>*Ernst-Thälmann</td><td>Saale Basin</td><td>G019670</td><td>unknown</td><td>4.27</td><td>13</td><td>24</td><td>436</td><td>53</td><td>Rote Fäule</td></tr><tr><td>**Lieth</td><td>North German Basin</td><td>G020486</td><td>outcrop</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>No</td></tr><tr><td>**Lieth</td><td>North German Basin</td><td>G020487</td><td>outcrop</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>No</td></tr><tr><td>**Lieth</td><td>North German Basin</td><td>G020488</td><td>outcrop</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>No</td></tr><tr><td>*Münzer / Sangerhausen</td><td>Saale Basin</td><td>G019421</td><td>unknown</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>Cu</td></tr><tr><td>*Koehnen / Nienstedt</td><td>Saale Basin</td><td>G019422</td><td>unknown</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>Pb (Cu)</td></tr><tr><td>*Fortschritt / Eisleben</td><td>Saale Basin</td><td>G019593</td><td>unknown</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>Cu</td></tr><tr><td>*Röhrig / Wettelrode</td><td>Saale Basin</td><td>G019594</td><td>unknown</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>Cu</td></tr><tr><td>*Münzer / Sangerhausen</td><td>Saale Basin</td><td>G019595</td><td>unknown</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>Cu</td></tr></tbody></table>

Uranium concentrations for wells Sangerhausen, Allstedt and Wallendorf are from Mohammedyasin *et al.* (2023). TOC content and Rock Eval data (HI, OI, Tmax) for the both Spremberg wells 121 and 115 are from Poetz *et al.* (2022).
<table><caption>Table S2 Data from open pyrolysis and thermovapourisation of Kupferschiefer T1 samples.</caption><thead><tr><th>Well /<br>Shaft*/Outcrop**</th><th>Sample no.</th><th>Depth<br>(m)</th><th>Uranium<br>(ppm)</th><th>Gas (C1-5)<br>in<br>pyrolysate<br>(%)</th><th>C6-14 in<br>pyrolysate<br>(%)</th><th>C15+ in<br>pyrolysate<br>(%)</th><th>Aromaticity<br>of pyrolysate<br>(%)</th><th>Gas (C1-5) after<br>thermovapourisation<br>(%)</th><th>C6-14 after<br>thermovapourisation<br>(%)</th><th>C15+ after<br>thermovapourisation<br>(%)</th></tr></thead><tbody><tr><td>Spremberg 121</td><td>G017734</td><td>1072.91</td><td>17</td><td>79.7</td><td>15.77</td><td>4.56</td><td>37.1</td><td>11.99</td><td>64.95</td><td>23.06</td></tr><tr><td>Spremberg 121</td><td>G017735</td><td>1072.99</td><td>20</td><td>78.7</td><td>16.08</td><td>5.18</td><td>36.3</td><td>13.93</td><td>60.50</td><td>25.57</td></tr><tr><td>Spremberg 121</td><td>G017736</td><td>1073.06</td><td>13</td><td>81.3</td><td>14.82</td><td>3.91</td><td>38.5</td><td>n.d.</td><td>n.d.</td><td>n.d.</td></tr><tr><td>Spremberg 121</td><td>G017737</td><td>1073.19</td><td>27</td><td>82.4</td><td>14.13</td><td>3.44</td><td>40.7</td><td>12.96</td><td>76.92</td><td>10.12</td></tr><tr><td>Spremberg 121</td><td>G017738</td><td>1073.24</td><td>43</td><td>85.1</td><td>12.14</td><td>2.82</td><td>45.2</td><td>n.d.</td><td>n.d.</td><td>n.d.</td></tr><tr><td>Spremberg 121</td><td>G017739</td><td>1073.30</td><td>38</td><td>82.9</td><td>13.62</td><td>3.45</td><td>43.5</td><td>n.d.</td><td>n.d.</td><td>n.d.</td></tr><tr><td>Spremberg 115</td><td>G017749</td><td>1318.48</td><td>12</td><td>78.1</td><td>16.34</td><td>5.53</td><td>36.2</td><td>n.d.</td><td>n.d.</td><td>n.d.</td></tr><tr><td>Spremberg 115</td><td>G017750</td><td>1318.54</td><td>10</td><td>76.8</td><td>16.46</td><td>6.76</td><td>34.4</td><td>n.d.</td><td>n.d.</td><td>n.d.</td></tr><tr><td>Spremberg 115</td><td>G017751</td><td>1318.74</td><td>26</td><td>82.0</td><td>14.78</td><td>3.23</td><td>39.1</td><td>n.d.</td><td>n.d.</td><td>n.d.</td></tr><tr><td>Spremberg 115</td><td>G017752</td><td>1318.85</td><td>n.d.</td><td>76.9</td><td>17.05</td><td>6.05</td><td>43.3</td><td>n.d.</td><td>n.d.</td><td>n.d.</td></tr><tr><td>Spremberg 115</td><td>G017753</td><td>1318.87</td><td>41</td><td>84.3</td><td>12.60</td><td>3.12</td><td>45.7</td><td>n.d.</td><td>n.d.</td><td>n.d.</td></tr><tr><td>Sangerhausen 102/80</td><td>G018873</td><td>430.05</td><td>12</td><td>94.2</td><td>5.84</td><td>0.00</td><td>72.1</td><td>70.86</td><td>29.14</td><td>0</td></tr><tr><td>Sangerhausen 102/80</td><td>G018874</td><td>430.08</td><td>14</td><td>89.3</td><td>10.51</td><td>0.17</td><td>89.3</td><td>50.84</td><td>48.26</td><td>0.9</td></tr><tr><td>Sangerhausen 102/80</td><td>G018875</td><td>430.16</td><td>30</td><td>89.9</td><td>9.31</td><td>0.77</td><td>80.4</td><td>40.78</td><td>46.15</td><td>13.07</td></tr><tr><td>Sangerhausen 102/80</td><td>G018876</td><td>430.19</td><td>32</td><td>89.6</td><td>9.50</td><td>0.95</td><td>49.0</td><td>34.03</td><td>44.91</td><td>21.06</td></tr><tr><td>Sangerhausen 102/80</td><td>G018877</td><td>430.23</td><td>38</td><td>91.2</td><td>6.74</td><td>2.02</td><td>50.9</td><td>51.37</td><td>31.99</td><td>16.65</td></tr><tr><td>Sangerhausen 102/80</td><td>G018878</td><td>430.28</td><td>91</td><td>93.3</td><td>5.75</td><td>0.92</td><td>61.3</td><td>31.17</td><td>49.4</td><td>19.43</td></tr><tr><td>Sangerhausen 102/80</td><td>G018879</td><td>430.33</td><td>94</td><td>96.1</td><td>3.00</td><td>0.94</td><td>62.6</td><td>54.87</td><td>37.05</td><td>8.07</td></tr><tr><td>Allstedt 11/86</td><td>G018897</td><td>946.12</td><td>298</td><td>49.7</td><td>42.04</td><td>8.22</td><td>40.5</td><td>14.62</td><td>45.46</td><td>39.92</td></tr><tr><td>Allstedt 11/86</td><td>G018898</td><td>946.17</td><td>204</td><td>55.8</td><td>35.66</td><td>8.57</td><td>59.4</td><td>17.4</td><td>58.3</td><td>24.3</td></tr><tr><td>Allstedt 11/86</td><td>G018899</td><td>946.21</td><td>n.d.</td><td>60.6</td><td>29.04</td><td>10.39</td><td>88.5</td><td>41.49</td><td>44.01</td><td>14.5</td></tr><tr><td>Ig Wallendorf/Luppe 6/84</td><td>G018908</td><td>359.42</td><td>30</td><td>80.9</td><td>15.70</td><td>3.40</td><td>34.8</td><td>40.87</td><td>33.76</td><td>32.75</td></tr><tr><td>Ig Wallendorf/Luppe 6/84</td><td>G018909</td><td>359.45</td><td>29</td><td>84.4</td><td>12.35</td><td>3.25</td><td>40.7</td><td>26.85</td><td>22.91</td><td>50.24</td></tr><tr><td>Ig Wallendorf/Luppe 6/84</td><td>G018910</td><td>359.5</td><td>23</td><td>81.0</td><td>15.02</td><td>4.03</td><td>31.7</td><td>26.73</td><td>39.4</td><td>33.87</td></tr><tr><td>Ig Wallendorf/Luppe 6/84</td><td>G018911</td><td>359.55</td><td>39</td><td>85.5</td><td>12.51</td><td>2.01</td><td>38.7</td><td>21.11</td><td>48.2</td><td>30.69</td></tr><tr><td>Ig Wallendorf/Luppe 6/84</td><td>G018912</td><td>359.6</td><td>55</td><td>87.7</td><td>10.45</td><td>1.88</td><td>47.0</td><td>21.91</td><td>33.43</td><td>44.66</td></tr><tr><td>Ig Bottendorf -01-2021</td><td>G020229</td><td>107.75</td><td>47</td><td>49.0</td><td>41.0</td><td>10.0</td><td>43.2</td><td>4.0</td><td>57.0</td><td>39.0</td></tr><tr><td>Ig Bottendorf -01-2021</td><td>G020230</td><td>107.72</td><td>75</td><td>50.0</td><td>41.0</td><td>9.0</td><td>45.8</td><td>3.0</td><td>66.0</td><td>31.0</td></tr><tr><td>Neuenbuch</td><td>G019526</td><td>383.49</td><td>n.d.</td><td>38.6</td><td>51.3</td><td>22.7</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td></tr><tr><td>Zeitlofs</td><td>G019527</td><td>533.60</td><td>n.d.</td><td>58.0</td><td>34.8</td><td>14.7</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td></tr><tr><td>Kruemmebuch</td><td>G019528</td><td>463.30</td><td>n.d.</td><td>60.2</td><td>48.6</td><td>3.1</td><td>64.8</td><td>n.d.</td><td>n.d.</td><td>n.d.</td></tr><tr><td>*Ernst-Thälmann</td><td>G019669</td><td>unknown</td><td>119</td><td>93.4</td><td>4.32</td><td>2.33</td><td>78.3</td><td>13.74</td><td>69.07</td><td>17.19</td></tr><tr><td>*Ernst-Thälmann</td><td>G019670</td><td>unknown</td><td>53</td><td>92.6</td><td>5.25</td><td>2.16</td><td>75.9</td><td>32.00</td><td>42.62</td><td>25.39</td></tr><tr><td>**Lieth</td><td>G020486</td><td>outcrop</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td></tr><tr><td>**Lieth</td><td>G020487</td><td>outcrop</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td></tr><tr><td>**Lieth</td><td>G020488</td><td>outcrop</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td><td>n.d.</td></tr><tr><td>*Münzer/Sangerhausen</td><td>G019421</td><td>unknown</td><td>n.d.</td><td>89.53</td><td>9.79</td><td>0.68</td><td>61.9</td><td>50.70</td><td>46.57</td><td>2.73</td></tr><tr><td>*Koehnen/Nienstedt</td><td>G019422</td><td>unknown</td><td>n.d.</td><td>92.39</td><td>7.38</td><td>0.23</td><td>78.8</td><td>69.38</td><td>22.30</td><td>8.31</td></tr><tr><td>*Fortschritt/Eisleben</td><td>G019593</td><td>unknown</td><td>n.d.</td><td>84.98</td><td>13.44</td><td>1.57</td><td>51.3</td><td>38.04</td><td>55.39</td><td>6.57</td></tr><tr><td>*Röhrlig/Wetterlode</td><td>G019594</td><td>unknown</td><td>n.d.</td><td>80.40</td><td>17.46</td><td>2.13</td><td>40.0</td><td>23.35</td><td>66.26</td><td>10.39</td></tr><tr><td>*Münzer/Sangerhausen</td><td>G019595</td><td>unknown</td><td>n.d.</td><td>85.65</td><td>13.37</td><td>0.97</td><td>54.2</td><td>27.22</td><td>67.79</td><td>4.98</td></tr></tbody></table>
Supplementary Figures

<figure><img src="image_10.png" /><figcaption>**Figure S-1** (a) Exemplified core showing the Kupferschiefer T1, underlain by Rotliegend red beds and overlain by carbonate Ca1, well Spremberg Cu Sp 76/60 (not presented in Fig. 1). (b) Sample G017754, well Spremberg 115, depth: 1318.88 m, BSE image of the transition from chalcopyrite-mineralised Rotliegend sandstone to Kupferschiefer T1. (c) Sample G019594, Röhrig shaft, Wettelrode, depth: unknown, BSE image of chalcopyrite filling dissolved calcite.</figcaption></figure>
<figure><img src="image_11.png" /><figcaption>**Figure S-2** Reflected light images of organic laminae in Kupferschiefer T1 in sample G020486 of the Lieth outcrop. (d) Left: UV illumination shows that the organic laminae do not fluoresce.</figcaption></figure>
<figure><img src="image_12.png" /><figcaption>**Figure S-3** BSE images of interfaces (white arrows) between OM and metal sulphides where OM is (intra)seal for mineralization. (a) Sample G019421, Thomas-Münzer shaft, Sangerhausen, depth unknown. (b) Sample G019595, Thomas-Münzer shaft, Sangerhausen, “Grobe Lette”, taken from mine dump. (c) Sample G017739, well Spremberg 121, 1073.30 m depth. (d) Sample G019421, Thomas-Münzer shaft, Sangerhausen, depth unknown. (e) Sample G019421, Thomas-Münzer shaft, Sangerhausen, depth unknown. (f) Sample G019594, Röhrig shaft, Wettelrode, depth unknown.</figcaption></figure>
<figure><img src="image_13.png" /><figcaption>**Figure S-4** Imaging to demonstrate that organic laminae are dense and free of pores, here by example sample G020247 from well Ig Bottendorf-01-2021. (a) High-magnification scanning transmission electron microscopy (STEM) image of OM as matrix with pyrite, sphalerite, and calcite which is surrounded by partial open interface to OM. (b) TEM Bright Field image showing pyrite in dense OM. (c) TEM Bright Field image showing direct interface of pyrite and dense OM. (d–f) High-angle annular dark field (HAADF) images of dense OM along a transect away from pyrite (see insets in (c)).</figcaption></figure>
<figure><img src="image_14.png" /><figcaption>**Figure S-5** Open pyrolysis chromatograms of selected samples representing a transect from the Rote Fäule facies into the Cu-PB-Zn zonation. Note the highest uranium concentrations at the interface between Rote Fäule and Cu zone. Highest Cu concentrations occur in samples of the Cu zone when deposition took place close to the palaeoshore.</figcaption></figure>
<figure><img src="image_15.png" /><figcaption>**Figure S-6** Thermovaporisation chromatograms of selected samples representing a transect from the Rote Fäule facies into the Cu-PB-Zn zonation. Note the dichotomy of chromatogram patterns as samples away from the Rote Fäule facies desorb a pronounced content of higher molecular hydrocarbons (paraffinic signature; except for sample G018899).</figcaption></figure>
<figure><img src="image_16.png" /><figcaption>**Figure S-7** Triangle typing of petroleum type organofacies (according to Horsfield, 1989). Red circles show data from open-system pyrolysis GC-FID, green circles show data from thermovaporisation GC-FID. Yellow star symbols show data from samples of the Sangerhausen well gained by thermovaporisation GC-FID.</figcaption></figure>
Supplementary Information References

Belkhou, R., Stanescu, S., Swaraj, S., Besson, A., Ledoux, M., Hajlaoui, M., Dalle, D. (2015) HERMES: a soft X-ray beamline dedicated to X-ray microscopy. *Journal of Synchrotron Radiation* 22, 968–979.
https://doi.org/10.1107/S1600577515007778

Bernard, S., Brown, L., Wirth, R., Schreiber, A., Schulz, H.-M., Horsfield, B., Aplin, A.C., Mathia, E.J. (2013) FIB-SEM and TEM Investigations of an Organic-rich Shale Maturation Series from the Lower Toarcian Posidonia Shale, Germany: Nanoscale Pore System and Fluid-rock Interactions. In: Camp, W.K., Diaz, E., Wawak, B. (Eds.) *Electron Microscopy of Shale Hydrocarbon Reservoirs*. American Association of Petroleum Geologists, Tulsa, AAPG Memoir 102, 53–66. https://doi.org/10.1306/13391705M1023583

Hartwig, A., Schulz, H.-M. (2010) Applying classical shale gas evaluation concepts to Germany—Part I: The basin and slope deposits of the Stassfurt Carbonate (Ca2, Zechstein, Upper Permian) in Brandenburg. *Chemie der Erde* 70, Supplement 3, 77–91. https://doi.org/10.1016/j.chemer.2010.05.012

Horsfield, B. (1989) Practical criteria for classifying kerogens: Some observations from pyrolysis-gas chromatography. *Geochimica et Cosmochimica Acta* 53, 891–901. https://doi.org/10.1016/0016-7037(89)90033-1

Le Guillou, C., Bernard, S., De la Pena, F., Le Brech, Y. (2018) XANES-Based Quantification of Carbon Functional Group Concentrations. *Analytical Chemistry* 90, 8379–8386. https://doi.org/10.1021/acs.analchem.8b00689

Mohammedyasin, M.S., Magnall, J.M., Gleeson, S.A., Schulz, H.-M., Schleicher, A.M., Stammeier, J.A., Ehling, B.-C. (2023) Diagenetic History and Timing of Cu and Zn-Pb Sulfide Mineralization in the Permian Kupferschiefer System, Saale Subbasin, Eastern Germany. *Economic Geology* 118, 1467–1494. https://doi.org/10.5382/econgeo.5015

Poetz, S., Liu, Y., Magnall, J.M., Vieth-Hillebrand, A., Yang, S., Göthel, M., Gleeson, S.A., Schulz, H.-M. (2022) Signals of low grade organic matter alteration in the Upper Permian Kupferschiefer (Spremberg area, Eastern Germany) – A by-product of copper mineralization? *Organic Geochemistry* 169, 104421. https://doi.org/10.1016/j.orggeochem.2022.104421

Rippen, D., Littke, R., Bruns, B., Mahlstedt, N. (2013) Organic geochemistry and petrography of Lower Cretaceous Wealden black shales of the Lower Saxony Basin: The transition from lacustrine oil shales to gas shales. *Organic Geochemistry* 63, 18–36. https://doi.org/10.1016/j.orggeochem.2013.07.013

Stammeier, J., Wiedenbeck, M., Glodny, J., Sigmarsson, O., Potts, P.J., Webb, P. (2023) Three Icelandic basalts for resampling of BIR basalt for production of ISO-certification of whole rock powder. *GFZ Data Services*. https://doi.org/10.5880/GFZ.3.1.2023.005

Swaraj, S., Belkhou, R., Stanescu, S., Rioult, M., Besson, A., Hitchcock, A.P. (2017) Performance of the HERMES beamline at the carbon K-edge. *Journal of Physics: Conference Series* 849, 012046. https://doi.org/10.1088/1742-6596/849/1/012046

Wang, J., Morin, C., Li, L., Hitchcock, A.P., Scholl, A., Doran, A. (2009) Radiation damage in soft X-ray microscopy. *Journal of Electron Spectroscopy and Related Phenomena* 170, 25–36. https://doi.org/10.1016/j.elspec.2008.01.002

Wirth, R. (2009) Focused Ion Beam (FIB) combined with SEM and TEM: Advanced analytical tools for studies of chemical composition, microstructure and crystal structure in geomaterials on a nanometre scale. *Chemical Geology* 261, 217–229. https://doi.org/10.1016/j.chemgeo.2008.05.019

Yang, S., Schulz, H.-M., Horsfield, B., Schovsbo, N.H., Grice, K., Zhang, J. (2020) Geological alteration of organic macromolecules by irradiation: Implication for organic matter occurrence on Mars. *Geology* 48, 713–717. https://doi.org/10.1130/G47171.1