Temporal Evolution of Faults in the Southern German Molasse Basin: A Case Study of the Wolftratshausen Geothermal Prospect, Germany

Abstract

Recently, foreland basins have become prime targets to host geothermal resources because of the existence of deep aquifers. Understanding of tectonic evolution and fault kinematics is crucial to evaluate the potential for geothermal energy production. Based on a 3D seismic survey, acquired 30 km south of Munich, we analyse fault patterns within the Upper Jurassic carbonate reservoir and its Molasse overburden within the geothermal prospect of Wolfratshausen, in the southern German Molasse Basin. To determine the temporal activity of the interpreted faults, we built a 3D geological model, from which we derived juxtaposition diagrams of the faulted strata and thickness maps of seismic horizons. We show that the strata at Wolfratshausen underwent different deformation phases; extension in the pre- and early-orogenic stages of basin formation and contraction in the Middle Miocene. Furthermore, the deformation style at this part of the basin is characterised by decoupled faulting. The identified structures, their temporal activity, and deformation style indicate active stress regime and thus provide an insight into the hydraulic transmissivity of the fault zones for geothermal exploration.