Geochemistry, Geophysics, Geosystems

Abrupt climate-induced changes in carbonate burial in the Arabian Sea: Causes and consequences



We present high-resolution records of aragonite contents and pteropods abundance in two sediment cores (SK 17 and MD 76–131) within the Oxygen Minimum Zone (OMZ) of the eastern Arabian Sea. We show large increases in aragonite contents during glacial and particularly during stadials (Heinrich Events). Using aragonite content, pteropods abundance, organic carbon percentage, and abundance of fertile (eutrophic) species of planktonic foraminifer, we demonstrate that aragonite contents in the eastern Arabian Sea primarily reflects preservation linked to the deepening of Aragonite Compensation Depth (ACD) in the Arabian Sea. We show that these aragonite preservation events correspond with time equivalents of Heinrich Events when Arabian Sea experienced large declines in monsoon-driven productivity and greater penetration of Antarctica Intermediate Water (AAIW). Thus, pteropod preservation in the Arabian Sea appears to be linked to rapid climate change through atmospheric and oceanic teleconnections. We suggest that the role of aragonite carbonate production and burial in margins and the resultant CO2 climate feedback to rapid climate changes remains poorly constrained.