The valley cryopediments in Eastern Siberia
DOI:
https://doi.org/10.26485/BP/1973/22/5Keywords:
pedimentation, subnival environment, cryogenic slope processes, slope backwearingAbstract
The paper concerns the problems of pedimentation in the subnival environment of Eastern Siberia (mainly in the area of the Stanovoj Range, the Elginskoye Plateau and the Čerski Range). A concave erosion surface at the foot of valley sides occurs herc, gently sloping to the valley bottoms. The erosion surface attains up to 3 km in width with an inclination of usually 3 to 10°. In some places the piedmont surface is bo und directly on the valley bottom, in other places on low river terraces of Middle up to Upper Pleistocene age. The gentle erosion surface usually extends headwards from the main valleys into the side valleys. The studied surface is cut in solid rocks and covered with a thin layer of slope deposits (usually 1-2 m only).
The erosion surface develops by backwearing of steep valley sides due to Pleistocene and present-day cryogenic slope processes. On steep slopes mainly frost weathering, frost creep and suffosion manifest themselves. These processes are mainly active in shallow dells. Sapping of the steep slope by nivation together with the dells activity are the main reasons for parallel slope recession. The foot is exposed by further transportation of materiał mainly due to frost heaving and solifluction. Linear transport on the gentle erosion surface is also concentrated in shallow dells.
The authors consider the gentle erosion piedmont surfaces a subnival variety of the pediments of arid and semi-arid regions and call them cryopediments.
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