Rock glaciers in the Ulakhan-Chistay ridge (axial part of the Chersky mountain range)

Abstract

The Ulakhan-Chistay Ridge is interesting by the fact that one of the most extensive mountain glaciations in northeast Russia is located here. In addition, there are widespread specific glacial-cryogenic formations  – stone glaciers related to glacial and periglacial processes. On the basis of geoinformation mapping on evidence of remote sensing of the Earth and field investigations within boundaries of the Ridge, 1812 stone glaciers of different morphological types in relation to the enclosing relief were found, among them 111 circus (corrie) and 1701 niche ones. In the group of corrie glaciers, the dominating units are the active forms (76). Some of them are distinctive in the complex structure with different age generations. Among the niche glaciers 948 active, 545 inactive, and 208 relict ones were determined. The analysis of frequency distributions has allowed establishing that the stone glaciers of the studied area are located within the interval of heights 550-2450 m above the sea level. However, the main part of the active formations are positioned at heights of 1500–1900 m. Field observations of stone glaciers were carried out in the upper part of the Kyureter River area that is on the eastern slope of the Ridge. Investigations did show that thicknesses of glaciers at the key area (site) did not exceed 50 m, and they probably consist of several coalesced lobes. Thus, they form polylobate stone glaciers which width may reach 610 m or more with the lobes extending for up to 340 m.