Late Holocene Glacier Dynamics in the Miyar Basin, Lahaul Himalaya, India

Abstract

Detailed field mapping of glacial and paraglacial landforms and optical dating from these landforms are used to reconstruct the early Holocene glaciation in the semi-arid region of Miyar basin, Lahaul Himalaya. The study identifies three stages of glaciation, of decreasing magnitude and termed, from oldest to youngest, the Miyar stage (MR-I), Khanjar stage (KH-II), and Menthosa advance (M-III). The oldest glacial stage (MR-I) has been established on the basis of detailed geomorphological evidence such as U-shaped valley morphology, trimlines, and truncated spurs. It is speculated to be older than the global Last Glacial Maximum (gLGM) based on the magnitude of ∆ELA (Equilibrium-Line Altitude, 606m). No evidence of glacier expansion recorded from the basin correlates with the period of the gLGM. The second stage (KH-II) is well represented by extensive depositional features such as lateral and terminal moraines, drumlins, and lacustrine fills that have been constrained within 10 ± 1 to 6.6 ± 1.0 ka (Optically stimulated luminescence-OSL-ages), dating it to the early Holocene advance following the Younger Dryas cooling event. Exceptionally young glacial records of expansion are limited within a few hundred meters of the present termini of tributary glaciers and correlates with the 18th-century cooling event. Records of this glacial advance, termed the Menthosa advance, are clearly noticed in some tributary valleys.

Glacio-archaeological evidence of permanent settlements within a glacier end moraine complex during 980-1840 AD: The Miyar Basin, Lahaul Himalaya, India

“…The basin extends from 32842 0 36 00 N to 33815 0 24 00 N and 76840 0 12 00 E to 7781 0 15 00 E, covering an area of $963.85 km 2 , of which $21.6% (208.2 km 2 ) is covered by the contemporary glaciers (as of 2016). The basin contains a cluster of 92 glaciers of varying dimensions and types, out of which Miyar glacier is the longest ($27 km) (Saini, 2012;Deswal et al, 2017). Topographically, the Miyar basin is sandwiched between the lofty Pir Panjal to the south and High Himalayan Range to the north.…”

“…Rowan (2016); Solomina et al (2016), and Xu and Yi (2014) summarise the glacial chronology and thereby constrain the timing, extent and frequency of glacier fluctuations. Studies from neighbouring regions suggest one (Sharma and Owen, 1996;Barnard et al, 2004a;Deswal et al, 2017) or two (Owen et al, 1996(Owen et al, ,1997(Owen et al, , 2001Taylor and Mitchell, 2000;Barnard et al, 2004b;Orr et al, 2018Orr et al, , 2017 episodes of glacier advance during the LIA period. In terms of the timing, studies suggest glacier expansion at $800 years BP and $200 years BP in the Upper Chandrabhaga basin and Zanskar (Owen et al, 1996(Owen et al, , 1997(Owen et al, , 2001Taylor and Mitchell, 2000;Orr et al, 2017Orr et al, , 2018; during 200-300 years BP in NW Garhwal (Sharma and Owen, 1996;Barnard et al, 2004a); during 600-140 years BP in the Gori Ganga basin (Barnard et al, 2004b); and at $150 years BP in the Miyar Basin (current study area) (Deswal et al, 2017).…”

Susceptibility of cariogenic microorganisms to phytoconstituents

“…To confirm the presence of viable microorganisms for the non-inhibitory concentrations, we used TCT (2, 3, 5 triphenyl tetrazolium chloride) dye, at a volume of 10 μL, to detect the activity of dehydrogenase enzymes involved in the cellular respiration process, making it possible to distinguish the live samples, (red-stained), from the dead samples which retain their color (Deswal and Chand, 1997).…”

Disentangling source of moisture driving glacier dynamics and identification of 8.2 ka event: evidence from pore water isotopes, Western Himalaya

“…The timings and duration of glacier fluctuations in Himalaya have been dated and reconstructed using cosmogenic radionuclides (CRN) and optically stimulated luminescence (OSL) dating techniques. We argue that depleted δ 18 O value and high d-excess values of δ 18 Oporewater during the Kulti glacier advance (11-10 ka) 11 , Gumba glacier advance (10-8 ka) 13 , Yunam valley glacier advance (7.9 ± 1-6.9 ± 0.9 ka) 14 and Kyambu glacier advance in diversified valleys of Himalaya took place due to the increased precipitation, transported by the midlatitude Westerlies. During these glacier events, the d-excess value is greater than 17, as demarcated by the blue dashed line (see Fig.…”

“…Existing glacier reconstructions from Himalaya are based on cosmogenic radionuclide dating (CRN) and optically stimulated luminescence (OSL) dating from different valleys, indicating that the Western Himalaya has experienced several glaciation stages in the past, e.g., the Chandra glaciation, Batal glaciation, Kulti glaciations and Sonapani glaciation in the past [10][11][12] . Although, adequate glacier chronologies have refined a number of glacial events over the last few years from different valleys of the Western Himalaya (i.e., Yunam valley, Miyar basin, and Karzok valley [13][14][15] ), however, driver of the source of precipitation contributing to the mountain glacier advances is not well understood and remains a topic of debate [10][11][12] . Moreover, the scarcity of ice core records from the Indian Himalaya makes it difficult to understand the role of precipitation and temperature in the Quaternary glaciations.…”