Heat Flow and Kinematics of the Rhenish Basin

The rank of organic matter dispersed in sediments of the Rhenish fold belt permits the evaluation of some structural and paleogeothermal aspects of the preceeding basin. Present anticlines apparently have developed from zones of relatively lesser basin subsidence with elevated heat flow. The internal structure of the basin filling produced by this pattern of subsidence supports the view of a former basin site on continental crust. The somewhat differing picture offered by rank data from the southern Massif, however, probably is influenced by synkinematic coalification due to tectonic superposition. The kinematics of the basin reflected in the mode of total subsidence and differential subsidence displays pronounced phases and rough synchronization throughout the basin. ‘Backstripping’ the sedimentary pile in order to neutralize its effect on subsidence reveals a strongly segmented mode of the purely tectonic subsidence with a rapid phase in Siegenian to Givetian time followed by a complete termination during the Upper Devonian. This, in combination with an unusually high and variable heat flow, the given pattern of subsidence, and the repeated volcanic activity suggests a past situation most closely resembling a continental back-arc region whose evolution is essentially controlled by crustal stretching and thermal processes.