New observations on present and prehistorical glacier-dammed lakes in the Shimshal valley (Karakoram Mountains)

In the upper Shimshal valley three glacier dams are present along a horizontal distance of only 25 km: the Khurdopin/Yukshin Gardan, Yazghil and Malungutti glaciers. Only a few decameters separate the glacier tongues from the opposite valley flanks. At some localities the drainage of the main river already takes place subglacially. About 20 glacial floods occurred in the last century in the Shimshal valley, some of them with devastating consequences. The erosion potential is clearly visible by the high loss of settlement areas of the villages Shimshal (3080 m) and Pasu (2450 m). In the past, the lake formation was mainly attributed to the Khurdopin dam. New field observations in summer 2001 revealed that advances of the Yukshin Gardan glacier can also contribute to a blockade of the Shimshal river. Slightest snow line depressions already would lead to numerous stable glacier dams and therefore to long-lasting ice-dammed lakes. Such a situation occurred during Neoglacial times, if not even during the Little Ice Age. Huge sequences of lake sediments, several decameters in height, evidence the prehistorical glacial lake ponding in the Karakoram valleys. (c) 2004 Elsevier Ltd. All rights reserved.