Abrupt weakening of the Indian summer monsoon at 8.2 kyr B.P.

• Published in: Earth and Planetary Science Letters
• Main Authors: Dixit, Yama, Hodell, David A., Sinha, Rajiv, Petrie, Cameron A.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Elsevier Science 2014
• Subjects: QE Geology; Indian; North Atlantic
• Online Access: http://repository.ias.ac.in/119406/; https://doi.org/10.1016/j.epsl.2014.01.026

An oxygen isotope record of biogenic carbonate from paleolake Riwasa in northwestern (NW) India provides a history of the Indian Summer Monsoon (ISM) from ∼11 to 6 kyr B.P. The lake was dry throughout the Late Glacial period when aeolian sands were deposited. Lacustrine sedimentation commenced in the early Holocene and the lake deepened significantly at ∼9.4 kyr B.P., indicating a strengthening of the ISM in response to summer insolation forcing. This high lake stand was interrupted by an abrupt desiccation, which is marked by a 12-cm limestone hardground that formed during a period of sub-aerial exposure after ∼8.3 kyr B.P. The base of the hardground surface coincides with the beginning of the ‘8.2-kyr B.P. cooling event’ in the North Atlantic that has been associated with a glacial outburst flood and slowdown of Atlantic meridional overturning circulation. The hardground provides robust evidence of a weakening of the ISM on the Indian subcontinent at ∼8.2 kyr B.P., and supports previous results of a strong teleconnection between monsoon Asia and North Atlantic climate. Lacustrine sedimentation resumed at ∼7.9 kyr B.P. suggesting the 8.2-kyr desiccation of paleolake Riwasa represented an abrupt response of the ISM to forcing from the North Atlantic.