Glacial to Holocene changes in sea surface temperature and seawater δ18O in the northern Indian Ocean

Abstract

Abstract Sea surface temperature (SST) and seawater δ18Osw records were generated from sediment cores located in the southern Bay of Bengal (SBOB) and the northeastern Arabian Sea (NEAS) to understand glacial to Holocene changes in the hydrography of these regions. This was accomplished through the use of paired δ18O and Mg/Ca measurements in planktic foraminifera (Globigerinoides ruber) from two sediment cores; SK157-14 in the \{SBOB\} (lat. 5°11′N; long. 90°05′E; water-depth 3306 m) and SK148-21 in the \{NEAS\} (lat. 21°29′N, long. 67°01′E; water-depth 1900 m). The results suggest significant changes in \{SST\} and δ18Osw since last glacial period. The glacial \{SSTs\} in the \{SBOB\} and the \{NEAS\} were lower by ~ 2–2.5 °C relative to the Holocene. The deglacial period in both cores is characterized by significant variations in \{SSTs\} and seawater δ18Osw. The Dansgaard-Oeschger (DO) cycles and Heinrich events are strongly expressed in \{SST\} and δ18Osw records of the \{SBOB\} core. These records support a strong control of atmospheric-oceanic changes in the northern high latitude on thermal state of the SBOB. The \{SST\} time series in both these regions indicates a sudden and abrupt increase in temperature at the end of last glacial maximum. The \{SST\} time series in the \{NEAS\} core \{SK\} 148-21 reveals an intensification of the northeast monsoon during the last glacial maximum.