Indian Ocean Circulation and Productivity during the Last Glacial Cycle

• Main Authors: Er M. Piotrowski, Virupaxa K. Banakar, Adam E. Scrivner, Albert Galy, Aileen Dennis
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Indian; Southern Ocean; NADW; North Atlantic Deep Water; North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.581.4729; http://drs.nio.org/drs/bitstream/2264/3372/1/Earth_Planet_Sci_Lett_285_179a.pdf

The Indian Ocean is an important part of the global thermohaline circulation system, receiving deep waters sourced from the Southern Ocean and being the location of upwelling and surface-ocean current flow, which returns warm and salty waters to the Atlantic. It is also an ideal location to reconstruct the link between thermohaline circulation and deep-water nutrient contents. No mixing occurs between major deep-water masses along flow paths within the Indian Ocean, so changes in water-mass provenance reflect changes in deep-ocean circulation while nutrient contents reflect addition and dissolution of organic matter. We present neodymium (Nd) and carbon (C) isotope records, proxies of water-mass provenance and nutrient contents, respectively, from an equatorial Indian Ocean core (SK129−CR2) spanning the last 150 kyr. The Nd isotope record shows that an increased proportion of North Atlantic Deep Water (NADW) reached the Indian Ocean during interglacials (marine isotope stages, MIS 1 and 5), and a reduced proportion during glacials (MIS 2, 4, and 6), and also that changes occurred during MIS 3. The magnitude and timing of deglacial and some MIS 3 variability is very similar to those in the RC11−83/TNO57−21 South Atlantic deep Cape Basin Nd isotope record, suggesting