Optical chronology and climatic implication of glacial advances from the southern Ladakh Range, NW Himalaya, India

Abstract Morphological, sedimentological, and chronological evidence suggests the preservation of three glacial advances of decreasing magnitude in the Puche valley. The oldest Puche Glacier Advance-1 (PGA-1) is dated to the early Marine Isotopic Stage (MIS)-2 (31.5 ± 3.3 ka) that persisted until around the global Last Glacial Maxima (LGM) (22.7 ± 1.6 ka). The PGA-2 is dated to the post LGM (14.4 ± 1.0 ka) and perhaps was triggered by the meltwater pulse (1a?) cooling. The youngest PGA-3 remains undated and could be of Holocene age. The OSL ages suggest a greater role of westerlies in driving the glacier advances during the MIS-2 in the southern Ladakh Ranges and are at variance with the previous suggestions that recommended monsoon driven glacier advances. The moraines in the Puche glacier valley (near Leh), southern Ladakh Ranges are dated using optically stimulated luminescence (OSL) technique. The OSL ages compared to the previously obtained 10Be surface exposure ages are younger by a magnitude. The study explores the probable causes for the variance in the two chronologies and suggests employing multiple dating methods to minimize the uncertainty both in terms of age and climatic interpretation.