Results of deep-Seismic reflection investigations in the Rhenish Massif

Abstract

Within the “Deutsches Kontinentales ReflexionsSeismisches Programm” (= DEKORP) two deep-Seismic reflection lines in the Rhenish Massif were surveyed in 1986 and 1987. The Rhenish Massif is part of the Mid-European Variscides, an orogenic belt which developed in the Upper Devonian-Carboniferous. Devonian rocks crop out at surface with only few exceptions. The Rhenish Massif is bordered by two sedimentary troughs: the Subvariscan Foredeep in the north and the Hessian depression in the south. In east-west direction it is subdivided by the River Rhine and another depression, the so-called Eifel North-South-Zone.Both lines consist of two parts, respectively and cross the northern border of the Rhenish Massif. DEKORP 1A/B is located west of the River Rhine and was extended through the BELCORP group by 35 km in Belgium. The total length of the line is 145 km. DEKORP 2-North/2-North-Q is located east of the River Rhine and has a length of 220 km/60 km.The aim of these surveys was to investigate the crustal structure of the Rhenish Massif and its relation to the adjacent areas in the north and south. The results indicate the presence of NW-vergent tectonics the effects of which can be traced down to the deep parts of the crust. Horizontal compression must play a dominant role. Differences between the western and eastern parts of the Rhenish Massif, the “Faille du Midi” and a prominent fault at its northern border are evident.