Rainfall seasonality on the Indian subcontinent during the Cretaceous greenhouse

Ghosh, Prosenjit and Prasanna, K and Banerjee, Yogaraj and Williams, Ian S and Gagan, Michael K and Chaudhuri, Atanu and Suwas, Satyam (2018) Rainfall seasonality on the Indian subcontinent during the Cretaceous greenhouse. In: SCIENTIFIC REPORTS, 8 .

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Abstract

The Cretaceous greenhouse climate was accompanied by major changes in Earth's hydrological cycle, but seasonally resolved hydroclimatic reconstructions for this anomalously warm period are rare. We measured the delta O-18 and CO2 clumped isotope Delta(47) of the seasonal growth bands in carbonate shells of the mollusc Villorita cyprinoides (Black Clam) growing in the Cochin estuary, in southern India. These tandem records accurately reconstruct seasonal changes in sea surface temperature (SST) and seawater delta O-18, allowing us to document freshwater discharge into the estuary, and make inferences about rainfall amount. The same analytical approach was applied to well-preserved fossil remains of the Cretaceous (Early Maastrichtian) mollusc Phygraea (Phygraea) vesicularis from the nearby Kallankuruchchi Formation in the Cauvery Basin of southern India. The palaeoenvironmental record shows that, unlike present-day India, where summer rainfall predominates, most rainfall in Cretaceous India occurred in winter. During the Early Maastrichtian, the Indian plate was positioned at similar to 30 degrees S latitude, where present-day rainfall and storm activity is also concentrated in winter. The good match of the Cretaceous climate and present-day climate at similar to 30 degrees S suggests that the large-scale atmospheric circulation and seasonal hydroclimate patterns were similar to, although probably more intense than, those at present.

Item Type:	Journal Article
Publication:	SCIENTIFIC REPORTS
Publisher:	NATURE PUBLISHING GROUP, MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
Additional Information:	Copy right of this article belong to NATURE PUBLISHING GROUP, MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
Department/Centre:	Division of Mechanical Sciences > Centre for Earth Sciences Division of Mechanical Sciences > Divecha Centre for Climate Change Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	18 Jun 2018 15:44
Last Modified:	18 Jun 2018 15:44
URI:	http://eprints.iisc.ac.in/id/eprint/60041

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