NOAA/WDS Paleoclimatology - Arabian Sea NIOP905 87KYr Benthic Stable Isotope Data

STUDY NOTES: Benthic oxygen and carbon isotope data from the northwestern Arabian Sea measured on the epibenthic foraminifera C. kullenbergi. The data are from NIOP (Netherlands Indian Ocean Programme) Core 905, retrieved from the continental slope off Somalia in 1993 from a water depth of 1580 m. The age model is taken from Ivanochko 2005. Oxygen and carbon isotope records are based on averages of multiple single specimen analysis of the epibenthic foraminifera C. kullenbergi. In a few limited cases Cibicidoides spp. were used to avoid gaps in the record where C. kullenbergi was rare.
ABSTRACT SUPPLIED BY ORIGINATOR: During the last glacial period, polar ice cores indicate climate asynchrony between the poles at the millennial time-scale. Yet, surface ocean circulation in large parts of the globe varied in tune with Greenland temperature fluctuations suggesting that any anti-phase behavior to a substantial degree must lie in the deeper global ocean circulation which is poorly understood outside the Atlantic Ocean. Here we present data from the north-western Indian Ocean which indicate that the timing of maxima in northward extensions of glacial Antarctic Intermediate Water (GAAIW) coincides with dramatically reduced thermohaline overturn in the North Atlantic associated with the Heinrich-ice surge events (HE). The repeated expansion of the GAAIW during HEs, recorded far north of the equator in the Arabian Sea, suggests that southern hemisphere driven intermediate water mass variability forms an integral part of the inter-hemisphere asynchronous climate change behavior at the millennial time-scale.