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      https://www.ias.ac.in/article/fulltext/jess/121/01/0149-0163

    • Keywords

       

      Glacial advancements; NW Himalaya; Chorabari Glacier; equilibrium line altitude; luminescence dating.

    • Abstract

       

      Field geomorphology and remote sensing data, supported by Optical Stimulated Luminescence (OSL) dating from the Mandakini river valley of the Garhwal Himalaya enabled identification of four major glacial events; Rambara Glacial Stage (RGS) (13 ± 2 ka), Ghindurpani Glacial Stage (GhGS) (9 ± 1 ka), Garuriya Glacial Stage (GGS) (7 ± 1 ka) and Kedarnath Glacial Stage (KGS) (5 ± 1 ka). RGS was the most extensive glaciation extending for ∼6 km down the valley from the present day snout and lowered to an altitude of 2800 m asl at Rambara covering around ∼31 km2 area of the Mandakini river valley. Compared to this, the other three glaciations (viz., GhGS, GGS and KGS) were of lower magnitudes terminating around ∼3000, ∼3300 and ∼3500 m asl, respectively. It was also observed that the mean equilibrium line altitude (ELA) during RGS was lowered to 4747 m asl compared to the present level of 5120 m asl. This implies an ELA depression of ∼373 m during the RGS which would correspond to a lowering of ∼2°C summer temperature during the RGS. The results are comparable to that of the adjacent western and central Himalaya implying a common forcing factor that we attribute to the insolation-driven monsoon precipitation in the western and central Himalaya.

    • Author Affiliations

       

      Manish Mehta1 Zahid Majeed1 D P Dobhal1 Pradeep Srivastava1

      1. Wadia Institute of Himalayan Geology, 33 GMS Road, Dehra Dun 249 001, India.
    • Dates

       
  • Journal of Earth System Science | News

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