Formy glacjalne Baga-Chenteju

Abstract

The paper presents results of investigation carried out in July 1977 on the forms and deposits of younger phase of the latest glaciation in the Asaralt Massif in Baga-Chentej (Mongolia). The relief forms and deposits accurring are a clear evidence of a cirque-valley glaciation existing heve in the past. An interesting problem are the cirques being much better developed on the southern than on the northern massif side. Glacial cirques representing the latest glacial phase are developed in those sites mainly where vast and flat enough sub-ridge planations were present at the bases of steep slopes bordering the watershed flatnesses. The planations helped the snow accumulation. A significant role was played heve by a prevailing NE wind direction, the snows being transferred by the winds to the southern leeward massif side, like they are at present. The assymetry in glacier size indicates a high correlation of the glaciation type to the perglacial relief. The correlation was found by M. Klimashevski in the Carpathians (1960, 1964) and by L.N. Ivanovsky in the Altay Mountains (1961), it was also observed in the Asaralt Massif in the youngest phase of the latest glaciation. The dead-ice relief (melt moraines, rocky glaciers), an absence of recession moraines or glacifluvial deposits in the valleys dowstream the cirques indicate climatic conditions of deglaciation. These were low-dynamic glaciers which was mainly associated to small rainfall volume. Revere climatic conditions and mainly the low temperatures resulted in substantial ablation decrease. In most cirques, the glaciers were the dead ones. Rocky blocks and landslides falling on the glaciers from the cirque top sections resulted in their earlier standstill.