Factors responsible for driving the glaciation in the Sarchu Plain, eastern Zanskar Himalaya, during the late Quaternary

Abstract

ABSTRACTDetailed geomorphological investigation supported by field stratigraphy and optical dating enabled us to identify three major events of glaciation in the eastern Zanskar Himalaya (Sarchu Plain). The oldest and most extensive glaciation is the Sarchu Glaciation Stage‐1 (SGS‐1) that pre‐dates the Last Glacial Maximum (LGM) and is assigned to the cold and wet Marine Isotope Stage‐4 (MIS‐4). The second glacial advance (SGS‐2) is optically dated to ∼20 ka and the youngest SGS‐3 is assigned to the 8.2 ka cooling event. Evidence of deglaciation is preserved as outwash terrace gravels and is assigned to the pluvial MIS‐3 and the early Holocene (∼9 ka). Increased strength of westerlies (winter precipitation) and associated temperature decline were responsible for driving the glaciation in the study area, a conclusion that accords well with modern meteorological data showing a reasonable correlation between the modern equilibrium line altitude, enhanced mid‐latitude westerlies (winter precipitation) and winter temperatures. The phases of deglaciation occurred during periods of warmer climatic excursions. Overall a broad correspondence between the Sarchu Plain glaciation phases and northern latitude ice sheet dynamics is suggested, implying that the glaciers in the trajectory of the mid‐latitude westerlies are likely to respond in phase with northern latitude glaciation.