Reconstructed post gLGM glacier recession and climatic variability of the Changme Khangpu valley, Eastern Himalayas, INDIA

The glaciated Changme Khangpu basin (CKB) covering an area of 767.8 km², constitutes an important region in the Eastern Himalayas for palaeoclimate research to assess variability over recent geological times. Climatically, this part of the Himalayas is mainly controlled by the Indian Summer Monsoon (ISM). We provide a combination of multiproxy data, i.e., geomorphological, sedimentological, geochemical, Accelerator Mass Spectrometry ¹⁴C dating and Schmidt Hammer rebound value dating methods in reconstructing glacier and climatic changes related to the post global Last Glacial Maximum (gLGM) in the Changme Khangpu basin of the Sikkim Himalaya. The four set of well-preserved moraines depicted four advances of this glacier and palaeoclimate has been reconstructed after the Phase-II glacier advances i.e. post gLGM period. The post gLGM glacier recession in the Changme Khangpu (CK) valley witnessed a prolonged humid climate phase from <14.29 ± 0.22 ka to 7.08 ± 0.08 ka cal BP that inferred from the sedimentary log in this valley and incidentally correlate with the monsoonal reactivation (15 ka to 12 ka BP) in Southern Asia. This humid period was succeeded by dry climatic phases from 7.08 ka to 5.4 ka cal BP and from 5.18 to 4.65 ka cal BP, which well correlates with the dry phases in the Chopta valley, west of this area in Sikkim Himalaya. The glacier had receded from its Phase-III advance in between <4 and >1.3 ka BP. This period was followed by the active paraglacial fan formation and witnessed historical outburst events in this valley.

 

Keywords: Changme Khangpu glacier (Sikkim); Eastern Himalayas; Last Glacial Maximum; Palaeoclimate; Glacier geomorphology; 14C AMS dating; Chemical index of alteration.