A first look at past sea surface temperatures in the equatorial Indian Ocean from Mg/Ca in foraminifera

Abstract

Sea surface temperature (SST) for the central equatorial Indian Ocean, has been reconstructed over the last approx. 137 kyr, from Mg/Ca of the planktonic foraminiferal species Globigerinoides ruber. According to our record the equatorial Indian Ocean SST was approx. 2.1 degrees C colder during the last glacial maximum as compared to present times. The data further shows that the surface equatorial Indian Ocean was comparatively warmer during isotopic stage 5e than at present (approx. 29.9 vs approx. 28.5 degrees C). Comparison of the equatorial Indian Ocean SST with the Antarctic delta D and Greenland delta sup(18) O records, shows that the major high-latitude cooling/warming events are also present in the equatorial Indian Ocean SST variation record. Similarity between the equatorial Indian Ocean SST and the equatorial Pacific SST suggests the possibility of a common mechanism controlling the SSTs in both the equatorial Indian Ocean and the Pacific Ocean