Steep slopes in the Sudetes and their morphotectonic interpretation

Abstract

The Sudetes is a block-faulted mountain range in Central Europe, at the NE margin of the Bohemian Massif. In the late Cenozoic it has been subject to differential uplift and subsidence and currently represents a horst-and-graben structure, superimposed on older relief due to rock-controlled denudation and erosion. In this paper, the distribution of steep slopes (>>gt; 15° and >>gt; 25°) is analyzed using a Digital Elevation Model (DEM) of 50 m spatial resolution, and their morphotectonic significance is discussed. Steep slopes occur in four major settings: heavily dissected and most elevated highlands, straight mountain fronts, narrow sinuous escarpments, and deeply incised river valleys. The former in particular may indicate areas subject to recent uplift, which is followed by efficient fluvial incision, so that little pre-uplift topography has survived. The image of many mountain fronts on the slope map is rather poor, which may be explained by the mechanical weakness of the rock building the footwall. At the same time, the association of the majority of tectonically-induced steep slopes with the most resistant rocks suggests that the intensity of recent uplift is generally low compared with the long-term rates of denudation and erosion.