Late Quaternary glaciations in the Cogarbu valley, Bhutanese Himalaya

Abstract

This study investigates the late Quaternary glacial history of the Cogarbu valley on the northern slopes of the Bhutanese Himalaya using 10Be surface exposure dating. Five major glacial events were constrained based on 28 10Be exposure ages. The equilibrium line altitude (ELA) of the oldest and most extensive glacial event (M5–M9) is ∼489 m lower than the present, followed by four other events (M4, M3, M2 and M1) with ELA depressions of ∼452, ∼200, ∼76 and ∼42 m, respectively. The exposure ages of the oldest glacial event (M5–M9) are ∼23.4–19.1 ka, corresponding to the global Last Glacial Maximum (gLGM). The second (M4, ∼15.8 ka) and the third oldest events (M3, ∼11.5 ka) coincide with the Heinrich‐1 and Younger Dryas event, respectively. The fourth oldest glacial event (∼1.2–0.82 ka) occurred during the Late Holocene. The latest glacial event (∼0.77–0.53 ka) represents the Little Ice Age glacial advances. These glacial events are broadly synchronous with those from other regions across the monsoon‐influenced Himalaya. All these events occurred during the cold periods, despite relatively dry conditions. It appears that temperature is the major factor driving glacial fluctuations since the gLGM in the Bhutanese Himalaya.

Influence of support layer and PDMS coating conditions on composite membrane performance for ethanol/water separation by pervaporation

“…In “dip‐coating,” the top layer is formed by immersing the substrate in an appropriate polymer solution . Some studies have investigated the effects of PDMS coating conditions, such as concentration of coating solution, solvent type, and number of coatings on performance of the prepared composite membranes . However, the effect of variation in dip time for coating the PDMS solution has not been reported so far.…”

Modelling Glacier Evolution in Bhutanese Himalaya during the Little Ice Age

“…1; Fig. 2a-2c; Marzeion et al, 2012;Maussion et al, 2019;Peng et al, 2019Peng et al, , 2020Parkes, et al, 2020). Our study revealed that the summer temperature plays a dominant role in controlling glacier changes at suborbital-scale.…”

“…The ongoing debate about the pattern of glacier evolution during the LIA is, in part, resulted from an imperfect understanding on how to cross validate observation with simulation, what the contribution of individual glacier to regional glacier evolution is, and how climate change drives glacier evolution (Goosse et al, 2018;Carrivick et al, 2019;Peng et al, 2019Peng et al, , 2020. Based on previous works, this study improves the understanding of the pattern of LIA glacier changes in Bhutanese Himalaya (BH; Fig.…”

“…For example, only one moraine was dated in Cogarbu valley (1256 ± 56 -1494 ± 43 CE; Fig. S1; Peng et al, 2019), but two substages were constrained in Lato valley, Lahul Himalaya (Saha et al, 2018), Langtang Khola valley, Nepal Himalaya (Barnard et al, 2006), and Gongotri Ganga valley, Garhwal Himalaya (Barnard et al, 2004). Liu et al (2017) Murari et al, 2014;Saha et al, 2019).…”

Effects of coating solvent and thermal treatment on transport and morphological characteristics of PDMS/Torlon composite hollow fiber membrane

“…PDMS is extensively used in various applications due to its low glass transition temperature ( T g = −123 °C), as well as its adequate thermal, chemical and oxidative stability . These properties are useful in preparing the silicone rubber membrane, but the PDMS should be crosslinked to stabilize it against flow into the support.…”