Glacial history of the Kuznetsky Alatay Mountains

摘要

Field investigations showed that the leeward slopes across the Kuznetsky Alatay Mountains (also the windward slopes in the Tigertysh ridge) are intensively eroded by glaciers and represent the classical type of "alpine-type landscape". Accumulative glacial landforms are developed in all types of glacial valleys. Study of five valleys (the Karatas, the Lower and the Upper Tayzhasu, Perekhodnya, the right source of the Small Kazyr Rivers) showed that four stadial moraine complexes can be identified. These moraines are very different by their morphology. They indicate the change of glaciation from large ancient valley glaciers to modern small cirque and slope glaciers. In this article, the first data are assessed about evolution of glaciers and climate in the Kuznetsky Alatay Mountains from the Last Glacial Maximum of Late Pleistocene (between 26,500 and 19,000-20,000 years BP) to nowadays on the basis of studies of glacial landforms, sedimentology, and biostratigraphy. In the Glacier inventory complied in 1970s-early 1980s, 91 glaciers were recorded in the Kuznetsky Alatay; however, some were erroneously identified as glaciers. The review of the current changes of modern glaciation of the Kuznetsky Alatay is made on the basis of repeated photographs and direct field measurements of 30 glaciers. 18 out of the 30 studied glaciers melted away completely, their area decreased from 1.4 to 0.5-0.3 km(2). Not all glaciers strongly degraded. Large cirque glaciers have not changed significantly. Over the past 110 years, the area of perennial snowfields in the Kuznetsky Alatay Mountains had reduced by 90 %. Over the century, the timberline has risen by about 50 m and is currently located at 1220-1200 m a.s.l.