Factors governing the pattern of glacier advances since the Last Glacial Maxima in the transitional climate zone of the Southern Zanskar Ranges, NW Himalaya Shubhra Sharma a, * , Anil D. Shukla b a Department of Earth and Environmental Science, IISER-Mohali, 140306, India b Physical Research Laboratory, Ahmedabad, 380009, India article info Article history: Received 11 July 2018 Received in revised form 6 October 2018 Accepted 8 October 2018 Keywords: Quaternary glaciation South-eastern Asia Geomorphology Glacial Optical chronology Monsoon Mid-latitude westerlies NW Himalaya abstract The present study investigates the relics of glacier advances and retreats in the transitional climatic zone of the Southern Zanskar Range, NW Himalaya in response to the temporal changes in the Indian Summer Monsoon (ISM) and mid-latitude westerlies. The study identifies four glacier advances which are named from the oldest to youngest as the Southern Zanskar Glacier Stage-4 (SZS-4) to SZS-1. The SZS-4 remains undated, however based on the existing chronology of the stratigraphically equivalent moraines/trim- lines in the region; it is conjectured to the Marine Isotope Stage-4 (MIS-4). The optical chronology ob- tained during the present study dates the SZS-3 to 22.8 ± 1.9e19.1 ± 1.9 ka which corresponds to the Last Glacial Maxima (LGM). The SZS-2 is dated to 15.7 ± 1.3e14.3 ± 1.3 ka (late Glacial period) whereas, based on the chronology of the recessional moraines (4.9 ± 0.4e4.5 ± 0.3 ka) the youngest SZS-1 is assigned to ~6 ka (mid-Holocene). The snout proximal moraines are attributed to the Little Ice Age (LIA)/historical times. The pulsating deglaciation associated with each advance since the LGM is represented by the recessional moraines and outwash gravel terraces. The older gravel terrace is dated between 10.8 ± 0.9 and 6.5 ± 0.5 ka and is attributed to SZS-2 deglaciation which is also manifested by the deposition of sandy facies in a relict lake sequence (6.7 ± 0.6 ka) and development of palaeosol (5.6 ± 0.5 ka). We propose that the glacial advances were triggered by the millennial scale cooling events during the pe- riods of strengthened westerlies and thus, suggest a synoptic scale coupling with the Northern Atlantic. The deglaciation is suggested to occur during the warmer ISM dominated phases. The late Holocene climatic instability that followed the recession of SZS-1 is manifested by the development of rhythmites (3.8 ± 0.5 ka), loess (2.5 ± 0.2 ka), and palaeosol (2189 ± 296 cal yr BP). © 2018 Elsevier Ltd. All rights reserved. 1. Introduction Glacier advances in Himalaya are attributed to spatial vari- ability in the Indian Summer Monsoon (ISM), mid latitude west- erlies and the topographically controlled micro-climatic conditions (Benn and Owen, 1998; Bohner, 2006; Owen and Dortch, 2014). The existing studies suggest that the maximum extent of Himalayan glaciers was reached during the Marine Isotope Stage (MIS-4) or 3 (local glacial maxima) and not during the global Last Glacial Maxima (LGM) (Benn and Owen, 1998; Owen et al., 2006; Seong et al., 2007 , 2009; Saha et al., 2016; Sharma et al., 2016). Instead during the global LGM (18e23 ka; Mix et al., 2001) there are suggestions that the glacier expansion was modest (Benn and Owen, 1998; Owen et al., 2002; Hughes et al., 2013; Owen and Dortch, 2014). In the NW Himalaya, Dortch et al. (2013) suggested that older advancements (>20 ka) were dictated by the ISM, while the younger advances were driven by the mid-latitude westerlies. The recent studies however, suggest that the maximum glacier expansion in the NW Himalaya perhaps occurred synchronously during the westerlies dominated MIS-4 and therefore, imply a coupling between the glacial expansion and the North Atlantic climatic oscillations for the older advances as well (Taylor and Mitchell, 2000; Nagar et al., 2013; Lee et al., 2014; Sharma et al., 2016; Ganju et al., 2018). Also, albeit variable in extent (Owen et al., 2002; Dortch et al., 2013), there seems to be a regional * Corresponding author. E-mail address: shubhra@iisermohali.ac.in (S. Sharma). Contents lists available at ScienceDirect Quaternary Science Reviews journal homepage: www.elsevier.com/locate/quascirev https://doi.org/10.1016/j.quascirev.2018.10.006 0277-3791/© 2018 Elsevier Ltd. All rights reserved. Quaternary Science Reviews 201 (2018) 223e240