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Linkage between seasonal insolation gradient in the tropical northern hemisphere and the sea surface salinity of the equatorial Indian Ocean during the last glacial period

DRS at CSIR-National Institute of Oceanography

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Title Linkage between seasonal insolation gradient in the tropical northern hemisphere and the sea surface salinity of the equatorial Indian Ocean during the last glacial period
 
Creator Saraswat, R.
Nigam, R.
Mackensen, A.
Weldeab, S.
 
Subject insolation
surface salinity
glaciation
foraminifera
Globigerinoides ruber
 
Description Paired stable oxygen isotope and Mg/Ca analyses in calcite tests of the mixed-layer-dwelling planktic foraminifer Globigerinoides ruber has been used to reconstruct equatorial Indian Ocean delta sup(18)O of seawater (delta sup(18)O sub(sw)) over the last approx. 137 thousand years. On the basis of ice-volume-corrected delta sup(18)O sub(sw) (delta sup(18)O sub(sw-ivc)), relative changes in sea surface salinity (SSS) have been estimated. The SSS estimates suggest three episodes of higher SSS (131-113 thousand years before present (kyr BP), 62-58 kyr BP, and 30-24 kyr BP) within the last glacial period as compared with the present. SSS comparison between interglacial episodes reveals that the surface seawater over the core site was significantly saltier during the penultimate interglacial than the Holocene. We suggest that the evolution of a seasonal insolation gradient between the Indian monsoon areas and the equator over the investigated time interval was instrumental in shaping the strength of the Indian winter and summer monsoons that left their imprints on the equatorial Indian Ocean SSS via freshwater input and wind-induced mixing. The study shows that the insolation difference between northern latitudes and the equator during winter affects monsoon strength in the Indian region, especially during cold intervals.
 
Date 2012-12-05T06:11:21Z
2012-12-05T06:11:21Z
2012
 
Type Journal Article
 
Identifier Acta Geologica Sinica, vol.86; 2012; 1265-1275
http://drs.nio.org/drs/handle/2264/4199
 
Language en
 
Rights An edited version of this paper was published by Springer/Geological Society of China. This paper is for R & D purpose and Copyright [2012] Springer.
 
Publisher Geological Society of China