Version 1
: Received: 26 September 2022 / Approved: 8 October 2022 / Online: 8 October 2022 (03:17:44 CEST)
How to cite:
Schneider, J.; Heine, F.; Heidinger, M.; Rosner, M. Transformational Geothermal Fluids in the Upper Jurassic Carbonate Reservoir of the South German Molasse Basin. Preprints2022, 2022100090. https://doi.org/10.20944/preprints202210.0090.v1
Schneider, J.; Heine, F.; Heidinger, M.; Rosner, M. Transformational Geothermal Fluids in the Upper Jurassic Carbonate Reservoir of the South German Molasse Basin. Preprints 2022, 2022100090. https://doi.org/10.20944/preprints202210.0090.v1
Schneider, J.; Heine, F.; Heidinger, M.; Rosner, M. Transformational Geothermal Fluids in the Upper Jurassic Carbonate Reservoir of the South German Molasse Basin. Preprints2022, 2022100090. https://doi.org/10.20944/preprints202210.0090.v1
APA Style
Schneider, J., Heine, F., Heidinger, M., & Rosner, M. (2022). Transformational Geothermal Fluids in the Upper Jurassic Carbonate Reservoir of the South German Molasse Basin. Preprints. https://doi.org/10.20944/preprints202210.0090.v1
Chicago/Turabian Style
Schneider, J., Michael Heidinger and Martin Rosner. 2022 "Transformational Geothermal Fluids in the Upper Jurassic Carbonate Reservoir of the South German Molasse Basin" Preprints. https://doi.org/10.20944/preprints202210.0090.v1
Abstract
The hydrochemical composition of the Upper Jurassic groundwaters in the South German Mo-lasse Basin (SGMB) indicates a heterogeneous and varying hydrogeochemical evolution, which contradicts previous flow model concepts. For this study, the data of 88 Tertiary, Cretaceous and Upper Jurassic groundwater samples were investigated for hydrochemical elements, 2H/18O-H2O isotopes, 87Sr/86Sr ratios as well as δ11B values. In addition, the geochemical composition, 87Sr/86Sr and δ11B values were analysed from depth-oriented Upper Jurassic rock samples to delineate water-rock interactions in the aquifer systems. Slightly elevated 87Sr/86Sr ratios of the carbonates compared to the typical signatures of marine Upper Jurassic carbonates indicate a synsedimentary radiogenic influence due to the erosion of the adjacent Bohemian Massif. However, these values cannot explain the significant higher Sr-isotope fingerprint of the groundwaters in the central SGMB. Different water types occur in the Upper Jurassic aquifer, primarily distinguished by the dominant cations, calcium or sodium with subclasses of the major anions. The calcium-dominated groundwaters occur mainly at the western and northern margins of the SGMB. The sodi-um-dominated ion exchange groundwaters instead dominate in the central and eastern SGMB. With increasing strontium content, the 87Sr/86Sr ratios of the Upper Jurassic groundwater samples either indicate a strontium uptake by carbonate of the host rocks, or a prevailing radiogenic sig-nature. This implies a basic interaction with terrestrial or marine Tertiary sediments. The results illustrate a downward transformational fluid flow systematic via the thick Tertiary sediment cover into the Upper Jurassic carbonate formation in the SGMB, highlighting a new understanding on the evolution of the Upper Jurassic groundwaters and a basin-wide recharge mechanism.
Keywords
Environmental isotope analyses; Strontium isotopes; Boron isotopes; Upper Jurassic carbonate aquifer; South German Molasse Basin; Tansformational Fluid Flow; Geothermal
Subject
Environmental and Earth Sciences, Geochemistry and Petrology
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
