The Cause of Carbon Isotope Minimum Events on Glacial Terminations

• Published in: Science
• Main Authors: Spero, Howard J., Lea, David W.
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Association for the Advancement of Science (AAAS) 2002
• Subjects: Antarctic; Pacific; Southern Ocean; Antarc*; North Atlantic Deep Water; North Atlantic
• Online Access: http://dx.doi.org/10.1126/science.1069401; https://www.science.org/doi/pdf/10.1126/science.1069401

The occurrence of carbon isotope minima at the beginning of glacial terminations is a common feature of planktic foraminifera carbon isotopic records from the Indo-Pacific, sub-Antarctic, and South Atlantic. We use the δ 13 C record of a thermocline-dwelling foraminifera, Neogloboquadrina dutertrei , and surface temperature estimates from the eastern equatorial Pacific to demonstrate that the onset of δ 13 C minimum events and the initiation of Southern Ocean warming occurred simultaneously. Timing agreement between the marine record and the δ 13 C minimum in an Antarctic atmospheric record suggests that the deglacial events were a response to the breakdown of surface water stratification, renewed Circumpolar Deep Water upwelling, and advection of low δ 13 C waters to the convergence zone at the sub-Antarctic front. On the basis of age agreement between the absolute δ 13 C minimum in surface records and the shift from low to high δ 13 C in the deep South Atlantic, we suggest that the δ 13 C rise that marks the end of the carbon isotope minima was due to the resumption of North Atlantic Deep Water influence in the Southern Ocean.