Evaluierung allgemeiner Modellvorstellungen zur großräumigen Fließsystematik im Oberjura-Aquifer (Molassebecken)

The exploration of geothermal resources in the South German Molasse Basin is currently focused on the Upper Jurassic aquifer, which includes the carbonates of the Upper Jurassic and the Lower Cretaceous (Purbeck). This aquifer, which is up to 600 m thick, extends from the Franconian and Swabian Alb in the north to the northern border of the Alps in the south. Understanding key hydrogeological aspects such as flow systems and identifying potential catchment areas is crucial for sustainable use of the reservoir for geothermal energy systems. Previous studies conducted with different objectives and over various time periods have shown conflicting results and failed to provide a unified hydrogeological picture. 24 geothermal power plants in the Molasse Basin are now in continuous production, which provides an opportunity for comprehensive, large-scale investigations of the Upper Jurassic aquifer. The objective of the review is to consolidate available data from groundwater dating, hydrochemical, hydraulic, and thermal field studies, as well as hypotheses for flow characterization within a unified framework to support a comprehensive discussion.