The deep carbon cycle is part of complex, interconnected processes in sedimentary basins. Our work to date has focused on scientific aspects of organic carbon conservation (e.g., formation of dark claystones, etc.) as well as applied aspects (e.g., shale gas, etc.). As part of the 2021-2027 research program "Changing Earth - Sustaining our Future" we are now dealing with topics that belong to research area 8 "Georesources for the energy transition and a high-tech society". Here we focus primarily on the influence of organic material on the formation of metal-rich dark claystones (e.g. Kupferschiefer, or copper slate), but also on the processes of graphite and natural hydrogen formation.

Our work is intended to form a bridge with which we can combine inorganic and organic geochemistry in order to be able to reconstruct an overall picture of the processes taking place. Here we also use Phreeqc to be able to make quantitative statements using chemical thermodynamics. The conceptual background of this work is the release of organic molecules into the porewater in sedimentary basins during the maturation or alteration of embedded organic material. If these have a low molecular weight and are therefore easily soluble in water (e.g. methane, carbon dioxide, acetic acid, etc.), the pore water is changed (pH, Eh). As a result, unstable minerals can be dissolved on the one hand, and new equilibria can arise between now stable mineral species on the other. Many well-known geochemical processes in the geological subsurface are part of complex hydrogeochemical reaction chains, such as thermochemical sulfate reduction. These interacting reaction chains are referred to as “Organic-Inorganic Interactions”, and these complex process networks are the research focus of our group.

Under the following key points you will find our publications from the last few years on the following topics:

• Organic-inorganic interactions in general
• Uranium-organic interactions
• Organic-inorganic interactions during metallogenesis
• Hydrogeochemical modelling
• ONGOING: Conventional and unconventional oil and gas

LATEST
Schulz, H.-M., Bernard, S., Perssen, F., and Stammeier, J. A.: Control of organic matter on metal mineralization in uranium-rich black shale “Kupferschiefer”. Geochemical Perspectives Letters (in press).

2024 TALKS
Schulz, H.-M., Bernard, S., Perssen, F., and Stammeier, J. A.: Organic-inorganic interactions as mineralization controls of the Early Permian sediment-hosted stratiform Cu deposit Kupferschiefer in Central Europe. Goldschmidt 2024, Chicago. 21st of August 2024.
Schulz, H.-M.: Organisch-anorganische Wechselwirkungen bei der Erzbildung im permischen Kupferschiefer. Kolloquiumsvortrag, Universität Jena. 27th of November 2024.

SAMPLING FOR "OM-metal interactions"
Christian Hallmann and Hans-Martin Schulz visited the Core repository in Adelaide and sampled Ediacaran sediments together with older and Cambrian sequences. This sampling campaign is part of investigations to unravel metal-OM interactions. After working in the core repository, outcrops in the Flinders Range were inspected.