Depth contour maps for the Rotliegend formations of the central Saar-Nahe Basin, SW Germany

In the past, some regions of the Saar-Nahe Basin were economically important due to coal mining for nearly 250 years. Today, in the frame of the energy transition, the Saar-Nahe Basin could be interesting for future geothermal heat extraction or heat storage in the subsurface. Information about depths, thicknesses and the nature of the rock formations are key-parameters for the evaluation of the economic efficiency of such projects. Our depth contour maps for some Rotliegend formations (Upper Carboniferous to Lower Permian) of the central Saar-Nahe Basin may facilitate such geothermal projects in the near future. The depth contour maps are based on 2D reflection seismic sections acquired by the oil industry and in the frame of the Deutsches Kontinentales Reflexionsseismisches Programm (DEKORP). Deep oil industry and shallow research well information were used to tie the seismic sections into the regional lithostratigraphy and for depth conversion. The surface geology from geological maps was used to trace the locations of faults and to localise the approximate position of formation tops mapped on seismic sections. Centres of the Saar-Nahe Basin subsidence are the Nahe Subbasin in the N and the Palatinate and the Pirmasens subbasins in the S of the Palatinate Anticline. Depths of the base of the Rotliegend deeper than 2000 m below sea level are reached in the subbasins whereas on the Palatinate Anticline pre-Rotliegend strata are locally exposed. During the Upper Rotliegend subsidence is most intense in the S (Palatinate and Pirmasens subbasins) and in the NE of the Saar-Nahe Basin.