Reduced oxygenation at intermediate depths of the southwest Pacific during the last glacial maximum

• Published in: Earth and Planetary Science Letters
• Main Authors: Durand, Axel, Chase, Zanna, Noble, Taryn L., Bostock, Helen, Jaccard, Samuel L., Townsend, Ashley T., Bindoff, Nathaniel L., Neil, Helen, Jacobsen, Geraldine
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2018
• Subjects: Southern-Ocean; New-Zealand; Marine-Sediments; Authigenic Uranium; Atmospheric Co2; Benthic Foraminifera; Antarctic Mode; Water Masses; Trace-Metals; Circulation; 1901 Earth and Planetary Sciences (miscellaneous); 1906 Geochemistry and Petrology; 1908 Geophysics; 1912 Space and Planetary Science; Antarctic; Southern Ocean; Pacific; New Zealand; Campbell Plateau; Antarc*
• Online Access: https://espace.library.uq.edu.au/view/UQ:cfc1df9

To investigate changes in oxygenation at intermediate depths in the southwest Pacific between the Last Glacial Maximum (LGM) and the Holocene, redox sensitive elements uranium and rhenium were measured in 12 sediment cores located on the Campbell and Challenger plateaux offshore from New Zealand. The core sites are currently bathed by Subantarctic Mode Water (SAMW), Antarctic Intermediate Water (AAIW) and Upper Circumpolar Deep Water (UCDW). The sedimentary distributions of authigenic uranium and rhenium reveal reduced oxygen content at intermediate depths (800-1500 m) during the LGM compared to the Holocene. In contrast, data from deeper waters (>= 1500 m) indicate higher oxygen content during the LGM compared to the Holocene. These data, together with variations in benthic foraminiferal delta C-13, are consistent with a shallower AAIW-UCDW boundary over the Campbell Plateau during the LGM. Whilst AAIW continued to bathe the intermediate depths (