High-frequency shifts in the Indian summer monsoon following termination of the YD event

Abstract

High-resolution multi-proxy records are pivotal to analyze Indian monsoon variability and its linkages with socio-economic growth in South Asia. To constrain short-term shifts in the Indian monsoon, we analyzed a speleothem sample from Meghalaya, northeastern India encompassing ∼15.4 to 10.1 kilo year before the Present (kyr BP). Our new speleothem data from Meghalaya suggests wet conditions in northeastern India during ∼15.4 to 12.9 kyr BP and ∼11.3 to 10.1 kyr BP, punctuated by a dry phase during ∼12.9 to 11.3 kyr BP including the Younger Dryas (YD) cold interval. We suggest a southward shift of the Intertropical Convergence Zone (ITCZ) in addition to weak Atlantic Meridional Overturning Circulation and land-sea heat contrast during the YD event leading to a weak Indian summer monsoon. The Northern Hemisphere atmospheric heating shift the ITCZ northward, but our data shows high-frequency shifts in the ISM during ∼11.3 to 10.1 kyr BP following termination of the YD cold event. This interval also shows a higher growth rate of the studied speleothem sample.