Geological interpretation of DEKORP deep seismic reflection profiles 1C and 9N across the variscan Saar-Nahe Basin southwest Germany

Abstract

Deep seismic reflection results across the Variscan Saar-Nahe Basin in southwest Germany, recorded as parts of DEKORP lines 1C and 9N, provide excellent images of the geometry of the basin and also of the structures in the underlying basement. This basement consists of several discrete units, some of which are highly-reflective, whereas others are essentially non-reflective; two of these units consist of well-layered dipping reflectors that are interpreted as having been telescoped by thrusting. Adjacent to the South Hunsrück Fault, the sedimentary pile within the Saar-Nahe Basin is over 8 km thick, but it thins dramatically towards the southeast and east. The position of continuous reflectors, both in the basin and the basement, indicate that the South Hunsruck Fault is subvertical and not a listric normal fault as proposed in several earlier interpretations. This implies that the basin did not form by normal extension but that it is transtensional in character, its geometry predominantly being controlled by strike-slip movements on the South Hunsruck Fault.