Cold-climate landform patterns in the Sudetes. Effects on lithology, relief and glacial history

Abstract

The Sudetes have the whole range of landforms and deposits, traditionally described as periglacial. These include blockfields and blockslopes, frostriven cliffs, tors and cryoplanation terraces, solifluction mantles, rock glaciers, talus slopes and patterned ground and loess covers. This paper examines the influence, which lithology and structure, inherited relief and time may have had on their development. It appears that different rock types support different associations of cold climate landforms. Rock glaciers, blockfields and blockstreams develop on massive, welljointed rocks. Cryogenic terraces, rock steps, patterned ground and heterogenic solifluction mantles are typical for most metamorphic rocks. No distinctive landforms occur on rocks breaking down through microgelivation. The variety of slope form is largely inherited from prePleistocene times and includes convexconcave, stepped, pedimentlike, gravitational rectilinear and concave free facetalus slopes. In spite of ubiquitous solifluction and permafrost creep no uniform characteristic ‘periglacial’ slope profile has been created. MidPleistocene trimline has been identified on nunataks in the formerly glaciated part of the Sudetes and in their foreland. Hence it is proposed that rockcut periglacial relief of the Sudetes is the cumulative effect of many successive cold periods during the Pleistocene and the last glacial period alone was of relatively minor importance. By contrast, slope cover deposits are usually of the Last Glacial age.