Description
The Münsterland Cretaceous Basin, North Rhine-Westphalia, Germany, has become an area of focus to exploit medium-deep to deep geothermal energy to provide climate-neutral, sustainable, and regional heat for residential, commercial, and industrial purposes. Despite hydrocarbon exploration during the last century and studies at the margins of the basin, the tectonic deformation in the central part of the basin and its effect on fluid pathways in the scope of hydrothermal systems, requires further investigation. In this study, we aim to characterize the deformation of the Cretaceous strata linked to underlying structural elements of the folded and faulted Paleozoic subsurface. We, therefore, interpret vintage seismic data of the hydrocarbon industry and the DEKORP project, recently acquired seismic data by the Geological Survey of North Rhine-Westphalia, and well data. The interpretations of Cretaceous marker horizons and structural elements indicate three SW-NE trending zones of intense deformation interpreted as inversion/wrench tectonics-related flower structures. Similar structures displaying evidence of polyphase deformation, a transtensional phase followed by a transpressional phase, have already been described for the southern part of the basin. The flower structures are located above Paleozoic anticlines, which we interpret to be tectonic weak zones. The formation of these features is explained by the regional stress field during reverse faulting activity along the Osning Fault Zone (Late Cretaceous) and the inversion of the Lower Saxony Basin during the Subhercynian inversion phase. Distinctly increased impedance contrasts in these fault zones and within their damage zones indicate enhanced porosity and possibly resulting permeability and is linked to the migration of fluids from deeper strata to the surface. The potentially enhanced petrophysical properties along the flower structures present preferential exploration targets for medium-deep geothermal systems in the central part of the Münsterland Cretaceous Basin.
