Palaeoclimatic conditions in the late Pleistocene Wadda Lake, eastern Kumaun Himalaya (India)

Abstract

An episode of neotectonic activity on an east-west trending fault in the zone of active intracrustal North Almora Thrust in the eastern Kumaun Himalaya resulted in the formation of a lake around 36,000 yr B.P. A 13 m continuous sequence, made up largely of carbonaceous mud, represents the lake that disappeared around 10,000 yr B.P. due to the revival of neotectonic activity. On the basis of radiocarbon dating, it appears that the rate of sedimentation varied from time to time during the existence of the lake. Palaeomagnetic studies show normal polarity except for a major deviation in the upper part of the section. Palynological investigations testify to the occurrence of three temperate humid and at least two well-defined arid climatic phases which are correlated with previously documented Late Quaternary climatic changes as recorded in the Himalaya as well as in Tibet. Around 10,000 yr B.P., widespread deposition of a tectonically induced debris flow occurred in the lake basin at the terminal stage of the lake's life. The two events, ca. 36,000 and 10,000 yr B.P., thus seem to represent two major neotectonic events in the Kumaun Lesser Himalaya.