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Increased glacial-age ventilation of the Chilean margin by Antarctic Intermediate Water
Citation
Muratli, JM and Chase, Z and Mix, AC and McManus, J, Increased glacial-age ventilation of the Chilean margin by Antarctic Intermediate Water, Nature Geoscience, 3, (1) pp. 23-26. ISSN 1752-0894 (2010) [Refereed Article]
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Copyright Statement
Copyright © 2011 Nature Publishing Group http://www.nature.com/
Official URL: http://www.nature.com/ngeo/journal/v3/n1/abs/ngeo7...
DOI: doi:10.1038/ngeo715
Abstract
Antarctic Intermediate Water is, at present, a water mass
that brings oxygen to intermediate depths throughout the
Southern Hemisphere oceans. Models have suggested that
intermediate waters had higher concentrations of oxygen
during the last glacial period1,2, consistent with globally
reduced denitrification3 and increased production of Antarctic
Intermediate Water4. However, some palaeoceanographic
reconstructions5,6 have indicated that production decreased in
the southeast Pacific Ocean at this time. Here we analyse the
concentrations of Re and Mn, the sedimentary concentrations
of which are controlled by the amount of dissolved oxygen
at the sea floor, from three sediment cores located along the
Chilean margin for the past 30,000 years. Our results from
the cores, which bracket the present-day water-column extent
of Antarctic Intermediate Water, show that the depth range
of well-oxygenated Antarctic Intermediate Water increased
off Chile during the Last Glacial Maximum. Dissolved oxygen
content began to decrease approximately 17,000 years ago,
coincident with rapid Antarctic warming and a poleward shift
of the southern westerly winds7. Our estimates of productivity
from accumulation rates of organic carbon and opal do not
co-vary with the seafloor oxygen variations, ruling out local
control of seafloor oxygenation. We conclude that the data
are best explained by a combination of increased oxygenation
and increased flux of Antarctic Intermediate Water during the
Last Glacial Maximum.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Research Division: | Earth Sciences |
| Research Group: | Oceanography |
| Research Field: | Chemical Oceanography |
| Objective Division: | Expanding Knowledge |
| Objective Group: | Expanding Knowledge |
| Objective Field: | Expanding Knowledge in the Earth Sciences |
| Author: | Chase, Z (Associate Professor Zanna Chase) |
| ID Code: | 67719 |
| Year Published: | 2010 |
| Web of Science® Times Cited: | 29 |
| Deposited By: | IMAS Research and Education Centre |
| Deposited On: | 2011-03-07 |
| Last Modified: | 2011-07-27 |
| Downloads: | 0 |
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