Original paper

Near-surface substrate on slopes of the Bunter Sandstone escarpment in the Odenwald region (Germany)

Semmel, Arno

Abstract

The foreland of the Bunter Sandstone escarpment in the Odenwald is largely blanketed by a periglacial basal layer made of Bröckelschiefer components. In most places, the basal layer is overlain by an upper layer. The latter is 30 to 40 cm thick and can also occur as bipartite layer. Due to its clayey substrate the corresponding soils are little permeable and thus, are affected by stagnant water. In general, the area comprises typically spruce habitats. On the escarpment front above the foreland Bröckelschiefer area, the slope is thickly coated by sandy debris layers, completely burying the sandstone bedrock of the Gelnhausen formation. The debris layers can be subdivided into a loess-free basal layer and a largely bipartite upper layer. Furthermore, a distinction between upper and top layer is possible. The top layer is not of anthropogenic origin, which is proved by features characteristic of periglacial gelifluction layers. In this context, a downslope orientation of longitudinal axes of large clasts appears regularly. The top layer consists of an enhanced content of local material in comparison to the upper layer. This fact is interpreted as the product of granular disintegration of a periglacial stone pavement present on top of the upper layer. Although it cannot be excluded that the granular disintegration and the downslope displacement of the sandy product also continued during the Holocene, however, it must be seen as a natural process.

Keywords

periglacial layerlaacher see tephrasoil geomorphologyodenwald tephra