Mid-depth sedimentary oxygenation variation in the western Pacific since the last glacial period: geochemical evidence from the Okinawa Trough
Abstract
In this study, we investigate a suite of sediment geochemical proxies (total organic carbon and carbonate contents, carbon to nitrogen ratio, aluminum and redox-sensitive elements) to reconstruct the history of sedimentary oxygenation in the northern Okinawa Trough (OT) over the last 50 thousand years (ka). Our data support the presence of oxygen-deficient deep waters during the late deglacial and Preboreal phases (15−9.5 ka), but oxygenated water column during the Heinrich Stadial 1 (HS1) and the Last Glacial Maximum (LGM). In contrast, increased sedimentary oxygenations are evident during the late glacial period and since 8.5 ka. Fluctuations of sedimentary oxygenation were widespread and apparently coherent over the entire North Pacific basin, reflecting broad effects of North Pacific Intermediate Water (NPIW) ventilation and export productivity. Intensified Kuroshio, however, improved the sedimentary oxygenation since 8.5 ka. We found the correspondence between changes in deglacial sedimentary oxygenation in the OT and Atlantic Meridional Overturning Circulation through the NPIW ventilation. The mechanism behind Atlantic-Pacific ventilation seesaw seems to be attributed to the perturbation of sea ice formation in high latitude North Pacific through atmospheric teleconnection.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFMPP41C1326Z
- Keywords:
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- 4845 Nutrients and nutrient cycling;
- OCEANOGRAPHY: BIOLOGICAL AND CHEMICAL;
- 4912 Biogeochemical cycles;
- processes;
- and modeling;
- PALEOCEANOGRAPHY;
- 4928 Global climate models;
- PALEOCEANOGRAPHY;
- 4964 Upwelling;
- PALEOCEANOGRAPHY