Relationship between morphology and glaciomarginal deposition in the foreland area of the Opava Mountains (S Poland)

Abstract

The glaciomarginal zone in front of the Opava Mountains (Eastern Sudetes) shows complex relief. This relief resulted during the Pleistocene in glaciomarginal sedimentation that differed from sedimentation in lowlands. Sedimentological analysis was carried out on deposits of the Odranian Glaciation, when the Scandinavian ice sheet reached its maximum extent in the Eastern Sudetes foreland. Three sites in the foreland of the Opava Mountains, situated in the upper reaches of the Troja River valley, were examined. It appears that the sedimentation was controlled primarily by the relief of the substratum, and changed with the position of the ice front. Glaciomarginal fans of different size formed in the Troja River valley, which was parallel to the ice sheet front. They passed distally into the valley outwash plain, the formation of which was also influenced by mountain rivers, the role of which though changed with time. Occasionally, water flowed from ice-dammed lakes in neighbouring valleys into the Troja River valley.