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Mainland Europe |
Institut für Geophysik, Universität Kiel, Federal Republic of Germany
In the area of the Variscides in Germany five seismic reflection surveys were carried out between 1968 and 1978. Near Aachen, at the very northern part of the Variscan deformation front, a thin-skinned overthrust fault was found, while farther south, at the Hunsrück border fault, a steep listric fault zone was mapped which seems to have been initiated as an overthrust, but developed into a deep reaching extensional fault during the post-Variscan formation of the Saar-Nahe trough. The reflection signature of the different experiments, the low seismic velocity in the middle and lower crust, and the generally small crustal thickness together with many geological and petrological observations are compatible with the assumption that during the Variscan orogenies an interstacking of predominantly sialic platelets took place in a generally high-temperature environment. The shifting of the collisional belts from SE to NW is opposite to that of the Appalachian orogenies, although time periods and tectonic framework were similar. A simplified concept of approaching thin sialic platelets toward the rugged remnants of the Caledonian orogeny is presented.
