The origin and evolution of Iskanderkul Lake in the western Tien Shan and related geomorphic hazards
Abstrakt
The origin and evolution of Iskanderkul Lake are studied in relation to geomorphic hazards within a broader area of interest. It is shown that the giant Kchazormech rockslide with its volume of masses of approximately 1 km3 entirely blocked the Iskanderdarja river valley, likely in the Middle Holocene, impounding thus the palaeolake of Iskanderkul.
Geomorphological evidence indicated that the palaeolake suddenly decreased its volume by 83% and its areal extent by 65% and released 0.84 +- 0.1 km3 of water. The present-day Iskanderkul Lake is therefore considered as a remnant of a much larger palaeolake of Iskanderkul.
Recent slope movements, incision and backward erosion of rockslide accumulation leading to the formation of a bypass gorge are documented. Current geomorphic hazards are outlined and the near-future evolution of Iskanderkul Lake is discussed with respect to the ongoing climate change suggesting a relatively low longevity of lakes in the Tien Shan.