Glacial and Periglacial Relief in the Făgăraş Mountain, with Special Focus on the Vâlsan River Basin

Abstract

The glacial modeling has created two well individualized geomorphologic landscapes in the Transylvanian Alpes: Borascu, characterized by the large extension of the platform and high peaks, and Fagaras, where cirques were multiplied and have developed until they reduced the platform to a very sharp ridge (gipfelflur). The layout of the main ridge on the West-East direction and the overall morphography of the two slopes, the northern one short and steep and the southern long, with gentle slopes, were also reflected in the way of development of glaciers in the Quaternary. In the Vâlsan basin there are distinguished some particularities of the glacial landform. Thus, the glacial landform of this sector of the Fagaras Mountains is characterized by a small steep (200-300m) which favored the development of a long glacial valley with gentle slopes and led to the forming of the moraines at the glacial valley floor. The Vâlsan glacial cirque is at 2300m altitude, is small and has small lakes. The bottom of the cirque is flat and is predominantly grafted on mica-schist and gneisses. The Vâlsan glacial valley is North-South oriented and has several glacial thresholds. The slopes surrounding the Vâslan valley are symmetrical, being affected by torrents and avalanches. Other characteristic landforms are: narrow glacial crests, glacial replats ridges, nunataks and moraines. The frost wedging caused the residual relief represented by sharp ridges, peaks, landforms of accumulation, debris cones, glacis, stone arches, protalus ramparts. Overall, the Vâlsan glacial valley is a typical valley where the intensive post-glacial processes have hidden most of the features resulting from the glaciers action, which kept the characteristic „U” shape and the glacial replats appear from place to place under glacises and rock debris.