The timing and extent of Quaternary glaciation of Stok, northern Zanskar Range, Transhimalaya, of northern India

Abstract

The glacial history of three tributary valleys (Namlung, Gopal Kangri and Stok Kangri) of the Stok valley, south of the Indus valley in the northern sector of the Zanskar Range, northern India is characterized using geomorphic mapping and cosmogenic 10Be surface exposure dating. The new glacial chronostratigraphy for the Stok valley is the first for the northern Zanskar Range and provides insights into the spatial variability of glaciation in the Himalayan-Tibetan orogen. This framework facilitates the understanding of the nature and the timing of landscape evolution and paleoenvironmental change in the Himalayan-Tibetan orogen. At least four glacial stages are evident within each of the tributary valleys of Gopal Kangri (MG1–MG4, youngest to oldest) and Stok Kangri (MS1–MS4) that feed into the Stok valley. With the exception of the MG4 glacial advance (~124ka) in Gopal Kangri, the Stok valley has preserved evidence of glaciations from ~50ka to the present. Equilibrium-line altitudes and glacier reconstructions for the Stok valley and its tributaries demonstrate that glaciations have become progressively less extensive through time. Former glacier extents of the Stok region are comparable in length with glacial advances during the last glacial cycle in eastern Zanskar and in the southern Ladakh Range to the south and north of the Indus valley, respectively. Landscape evolution in the study area has occurred across numerous glacial-interglacial cycles by a combination of glacial and fluvial processes and is similar to that of the Ladakh Range.