The Siachen Glacier: The Second Longest Glacier Outside the Polar Regions

Abstract

The Nubra Valley in Karakoram Himalaya is a highly glacierized valley with about 33 valley glaciers of different lengths and sizes. The glaciers occupy nearly 2/3rd of the total basin area. The most prominent and longest amongst them is the Siachen Glacier. This well-known glacier is a fine example of a compound and piedmont glacier. Glacier erosion has resulted in the development of a myriad of erosional and depositional features. These include numerous tributary glaciers with cirques, arêtes, horns, bergschrunds, moraines, supra-glacial streams and glacier lakes. Being a temperate glacier, the Siachen produces copious amount of runoff during ablation season in its proglacial streams. Heavy sediment load carried by the Nubra River has given rise to many glacio-fluvial depositional landforms and features such as outwash plains, braided rivers, alluvial fans, varved clays, etc. Evidence indicates three periods of glaciation in the area during the last ~145 ka. The role of tectonics in the late Quaternary period is also evident by way of at least three episodes of uplift, resulting in the formation of river terraces. There is no indication of significant recession of the Siachen Glacier snout during the last millennium.