Pollen records of vegetation dynamics, climate change and ISM variability since the LGM from Chhattisgarh State, central India

Abstract

Pollen records of a lacustrine sedimentary profile from the Chhattisgarh State, central India revealed that between ~22,200 and 18,658 cal yr BP, open vegetation occupied the landscape under a cool and dry climate, probably indicating a reduced monsoon precipitation. This cool and dry climate, influenced by weakening of the Indian Summer Monsoon (ISM), globally matches with the Last Glacial Maximum (LGM). Between ~18,658 and 7340 cal yr BP, under the influence of a warm and moderately humid climate with increased monsoon precipitation, the open vegetation was succeeded by open, mixed tropical deciduous forest. This open, mixed tropical deciduous forest continued to grow in the region, with an increase in the frequency of some of the tree taxa especially, between ~7340 and 1961cal yr BP under a warm and relatively more humid climate with increased monsoon precipitation, correlatable with the Holocene Climatic Optimum (HCO)/Holocene Thermal Maximum (HTM). Between ~1961 cal yr BP and the Present, dense, mixed tropical deciduous forest came into existence under a warm and relatively more humid climate with further increase in monsoon precipitation. The present study provides an unprecedented record of the vegetation dynamics, climate change and the ISM variability since the LGM from one of the poorly understood areas of the tropics where rainfall is essentially controlled by the monsoon (ISM) variability.