Multi-Proxy Record of Indian Summer Monsoon Variability Since the Last Glacial Maximum

Seasonal reversals in monsoon winds strongly influence rainfall patterns on the Indian sub-continent regulating the socio-economy of South Asian region. A stalagmite based multi-proxy approach using δ¹⁸O, δ¹³C and glycerol dialkyl glycerol tetraethers (GDGT) was used to characterize the hydro-climatic changes associated with Indian summer monsoon (ISM) since the last glacial maximum (LGM) revealing the coupled role of solar and ocean-atmospheric forcing. Marked with limited rainfall and sparse vegetation, LGM is observed to be 4 °C colder than Mid-Holocene. Consistent with other Asian monsoon records, the onset of early Holocene is marked with high rainfall with increased local vegetation. However, these changes are punctured by centennial scale dry events of global significance. Comparison with East-Asian stalagmite records reveals an in-phase relationship between the Indian and East Asian monsoons on centennial scale. Our study also suggests that Holocene changes in ISM activity are attributed to changes in Insolation and North Atlantic Oscillation and are also sensitive to El-Nino Southern Oscillation.