Investigating the sensitivity of glaciers to climate variability since the MIS-2 in the upper Ganga catchment (Saraswati valley), Central Himalaya Naresh Rana a,b , Shubhra Sharma c, ⁎, Sheikh Nawaz Ali d , Sunil Singh b , Anil Dutt Shukla e a National Center for Seismology, New Delhi 110003, India b Department of Geology, HNB Garhwal University, Srinagar Garhwal 246174, India c Department of Earth & Environmental Science, IISER Mohali, Mohali 140306, India d Birbal Sahni Institute of Palaeosciences, Lucknow 226007, India e Physical Research Laboratory, Navrangpura, Ahmedabad 380009, India abstract article info Article history: Received 7 July 2019 Received in revised form 26 August 2019 Accepted 27 August 2019 Available online 28 August 2019 Moraines, outwash gravel terraces, fluvial drapes and lacustrine sequences are used to infer the pattern of glacial fluctuations in the Saraswati valley (upper Ganga catchment). Located in transitional climatic zone between dry steppe of the Tibetan plateau in the north and sub-humid higher Himalaya in the south, the Saraswati valley has preserved evidence of four glacier advances. These are identified as the Saraswati Glacial Stage (SGS)-1 (oldest) to SGS-4 (youngest). Based on the relative dating and luminescence ages obtained on younger advances, the SGS- 1 is ascribed to pre-Marine Isotopic Stage (MIS)-2. The SGS-2 is dated to the MIS-2 (24.5 ± 2.8–21.2 ± 2.0 ka); the SGS-3 is speculatively ascribed to the Younger Dryas (YD) and the SGS-4 is suggested to be of the mid- Holocene (~6 ka) age. The bifurcated moraine ridges of SGS-2 represent standstill conditions during the post- Last Glacial Maximum (LGM) period. The deglaciation is represented by outwash gravel terraces, impounded sedimentary (lacustrine) sequences and fluvial drapes overlying and abutting the moraines are dated to early- mid (11.9 ± 0.9–7.5 ± 0.6 ka) and late Holocene (3.3 ± 0.2–1.7 ± 0.3 ka) intensified/moderate Indian Summer Monsoon. Considering the timing of glacial advances and stand-still condition, it is proposed that across the oro- graphic barrier (rain shadow valleys), glaciers responded sensitively to the intensified anticyclonic flow of the cooler Mid-latitude Westerlies; implying that in a monsoon dominated transient climatic zone, even the rain shadow valleys responded sensitively to temperature changes. © 2019 Elsevier B.V. All rights reserved. Keywords: Paleo-glaciation Central Himalaya Indian Summer Monsoon Mid-latitude Westerlies 1. Introduction There is a broad consensus that both the Indian Summer Monsoon (ISM) and the mid-latitude Westerlies dictated the pattern of late Qua- ternary glacial advances in the Himalayan region (Benn and Owen, 1998; Owen and Dortch, 2014 and references therein). However, but the exact mechanisms, timing, and geographical influence of the two weather systems and (a)synchronous response of the glaciers are still being debated (Scherler et al., 2010; Ali and Juyal, 2013; Owen and Dortch, 2014). The glacial advances/retreats show inter-regional variability on centennial to multi-millennial time scales; which are sug- gestively attributed to the variable response, preservation potential and/or chronological uncertainties (Benn and Owen, 1998; Richards, 2000; Owen et al., 2006; Owen et al., 2008; Ali et al., 2013; Dortch et al., 2013). Additionally, it has been observed that topography, precip- itation and temperature gradients also play a significant role in influencing the nature and extent of glaciers in the Himalayan region (Owen et al., 2008; Ali et al., 2013; Bisht et al., 2015; Sharma and Shukla, 2018). Moraines being the geomorphic expression of magnitude and extent of past glacier advances are used to infer (site-specific) past precipita- tion and temperature changes (Kerschner and Ivy-Ochs, 2008; Owen et al., 2008; Fu and Yi, 2009). Within the inherent limitation of chrono- metric resolution, and the poor preservation potential, the sedimentary archives of past glacial advances from multiple valleys can be used to understand the inter-hemispheric response of glaciers to the climate changes, regional/hemispheric atmospheric circulation patterns, estab- lish the regional correlations (Kirkbride and Winkler, 2012 and refer- ences therein), and help in testing of climate models (Bentley, 2010; Shulmeister et al., 2006). Unlike the Himalayan glaciers, some under- standing regarding the response of glaciers to quasi-periodic oscillations like El Nino Southern Oscillation (ENSO)/Arctic Oscillations (AO)/North Atlantic Oscillations (NAO) exists from other mountain valleys (Yu and Wright, 2001; Bradwell et al., 2006; Nesje et al., 2008). The limitation in the Himalayan region is largely because of the restricted chronometric data base. The problem is further compounded in the ISM dominated Geomorphology 346 (2019) 106854 ⁎ Corresponding author. E-mail address: shubshubhra@gmail.com (S. Sharma). https://doi.org/10.1016/j.geomorph.2019.106854 0169-555X/© 2019 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Geomorphology journal homepage: www.elsevier.com/locate/geomorph