Geomorphological processes in the Ala Archa National Park

Abstract

The Ala Archa National Park includes a wide range of geomorphological processes and landforms from the lowlands to the highest peaks. Here, we examine the distribution of geomorphological processes and landforms in the central part of the Tian Shan mountain range, Kyrgyzstan. Late Pleistocene glaciers shaped the landscape of the highest lands and left a moraine complex (M1) at the foot of the Ala Archa area at an elevation of 1580 m. The process of deglaciation followed different stages that favoured the individualization of glaciers within their respective valleys, with several moraine complexes (M2 and M3) distributed at elevations between 1680 and 3900 m. Today, debris-covered glaciers and rock glaciers constituted the lowest parts of the current glaciers, with their fronts located between 3350 and 3670 m. All these glacial features are being intensely reshaped by periglacial, alluvial and mass wasting processes on the steep slopes of this valley. The wide variety of landforms and sedimentary records existing in the area allows inferring a sequence of several environmental and climatic stages since the Late Pleistocene. Finally, the distribution of present-day geomorphological processes and active landforms identified in the Ala Archa National Park allowed establishing four morphodynamic belts: montane forests (<2000 m), subnival (2000-2800 m), nival (2800-3200 m), cryonival (>3200 m, excluding glaciated areas), and glacial (>3350 m between the glacier fronts and the highest peaks).