The N Variscan margin of the Ruhr coal district (Western Germany): structural style of a buried thrust front?

The Ruhr coal district represents part of an external fold and thrust belt of the Variscan orogen in central Europe. Extensive mining exposed molasse-type, coal-bearing clastic sequences of Upper Carboniferous age, deformed by folding and thrusting. Thrusts range in scale from decameters to 40 kilometers along strike but displacements are below 2.5 km. They are distributed in various stratigraphic levels and no regional detachment horizon is exposed. Displacement is mainly towards NW (towards the foreland) but also towards SE. The thrusts are bound to stockwerk-tectonics and die out towards depth frequently antithetic to the exposed strata. Folds vary in wavelength from decameters to more t…