Climatology of the Eastern Arabian Sea during the last glacial cycle reconstructed from paired measurement of foraminiferal δ18O and Mg/Ca

• Main Authors: V. K. Banakar, B. S. Mahesh, G. Burr, A. R. Chodankar
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarctic; Greenland; Antarc*
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.624.6952; http://drs.nio.org/drs/bitstream/2264/3592/1/Quat_Res_73_535a.pdf

Paired measurements of Mg/Ca and δ18O of Globigerenoides sacculifer from an Eastern Arabian Sea (EAS) sediment core indicate that sea-surface temperature (SST) varied within 2oC and sea-surface salinity within 2 psu during the last 100 ka. SST was coldest (~27oC) during Marine Isotope Stage (MIS) 4 and 2. Sea-surface salinity was highest (~37.5 psu) during most of the last glacial period (~60- 18 ka), concurrent with increased δ18OG.sacculifer and C/N ratios of organic matter and indicative of sustained intense winter monsoons. SST time series are influenced by both Greenland and Antarctic climates. However, the sea-surface salinity time series and the deglacial warming in the SST record (beginning at ~18 ka) compare well with the LR04 benthic δ18O-stack and Antarctic temperatures. This suggests a teleconnection between the climate in the Southern Hemisphere and the EAS. Therefore, the last 100-ka variability in EAS climatology appears to have evolved in response to a combination of global climatic forcings and regional monsoons. The most intense summer monsoons within the Holocene occurred at ~8 ka and are marked by SST cooling of ~1oC, sea-surface salinity decrease of 0.5 psu, and δ18OG.sacculifer decrease of 0.2 ‰.