Indian monsoon variability during the last 46 kyr: isotopic records of planktic foraminifera from southwestern Bay of Bengal

ABSTRACT The Indian monsoon carries large amounts of freshwater to the northern Indian Ocean and modulates the upper ocean structure in terms of upwelling and productivity. Freshwater‐induced stratification in the upper ocean of the Bay of Bengal is linked to the changes in the Indian monsoon. In th...

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Bibliographic Details
Published in:Journal of Quaternary Science
Main Authors: Gautam, P. K., Narayana, A. C., Kumar, P. Kiran, Bhavani, P. G., Yadava, M. G., Jull, A. J. T.
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2020
Subjects:
North Atlantic
Online Access:http://dx.doi.org/10.1002/jqs.3263
https://onlinelibrary.wiley.com/doi/pdf/10.1002/jqs.3263
https://onlinelibrary.wiley.com/doi/full-xml/10.1002/jqs.3263
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Summary:ABSTRACT The Indian monsoon carries large amounts of freshwater to the northern Indian Ocean and modulates the upper ocean structure in terms of upwelling and productivity. Freshwater‐induced stratification in the upper ocean of the Bay of Bengal is linked to the changes in the Indian monsoon. In this study, we test the usefulness of δ 18 O and δ 13 C variability records for Globigerina bulloides and Orbulina universa to infer Indian monsoon variability from a sediment core retrieved from the southwestern Bay of Bengal encompassing the last 46 kyr record. Results show that the northeast monsoon was dominant during the Last Glacial Maximum. Remarkable signatures are observed in the δ 18 O and δ 13 C records during the Marine Isotope Stage (MIS) 3 to MIS‐1. Our study suggests that Indian monsoon variability is controlled by a complex of factors such as solar insolation, North Atlantic climatic shifts, and coupled ocean–atmospheric variability during the last 46 kyr.

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