DEFINING THE TRANSITION IN STYLE AND TIMING BETWEEN QUATERNARY GLACIATION IN THE SEMI-ARID TRANSHIMALAYA AND THE MONSOON-INFLUENCED GREATER HIMALAYA IN NORTHERN INDIA

The nature and timing of Quaternary glaciation in the monsoon-influenced Greater Himalaya contrast markedly with glaciation to the north in the Transhimalaya. In the Greater Himalaya, Late Quaternary glaciations were very extensive whereas in the Transhimalaya, glaciation during the last few glacial cycles has become progressive very restricted in extent. To examine the transition between these regions, glaciations in the Puga and Karzok valleys, located in the Zanskar Range —a transitional zone between the Greater Himalaya and Transhimalaya—were examined using remote sensing, geomorphic mapping, and terrestrial ¹⁰Be cosmogenic nuclide surface exposure dating of boulders on moraines. Geomorphology and 47 ¹⁰Be ages indicate glacial advances in the Puga valley occurred during the penultimate glacial cycle, early last glacial cycle (~40 ka) and during the Holocene (~3 ka and 0.5 ka). In the Karzok valley, young moraines indicate advance at ~3.5 ka and large moraine complexes consisting of up to five individual ridges show multiple advances, and down-valley lateral moraines indicate an advance at >300 ka. Comparison with established records in the adjacent Greater Himalaya and Transhimalaya show that glaciation in the Puga and Karzok valleys is similar in nature to the Transhimalaya of Ladakh. This suggests that the transition to glaciation characterized by extensive Late Quaternary advances must occur further south and indicates a very steep climate transition between Zanskar and the Greater Himalaya.