Deglacial pattern of circulation and marine productivity in the upwelling region off central-south Chile


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Frank.Lamy [ at ] awi.de

Abstract

A high-resolution sea surface temperature and paleoproductivity reconstruction on a sedimentary record collected at 36°S off central-south Chile (GeoB 7165-1, 36°33′S, 73°40′W, 797 m water depth, core length 750 cm) indicates that paleoceanographic conditions changed abruptly between 18 and 17 ka. Comparative analysis of several cores along the Chilean continental margin (30°-41°S) suggests that the onset and the pattern of deglacial warming was not uniform off central-south Chile due to the progressive southward migration of the Southern Westerlies and local variations in upwelling. Marine productivity augmented rather abruptly at 13-14 ka, well after the oceanographic changes. We suggest that the late deglacial increase in paleoproductivity off central-south Chile reflects the onset of an active upwelling system bringing nutrient-rich, oxygen-poor Equatorial Subsurface Water to the euphotic zone, and a relatively higher nutrient load of the Antarctic Circumpolar Current. During the Last Glacial Maximum, when the Southern Westerlies were located further north, productivity off central-south Chile, in contrast to off northern Chile, was reduced due to direct onshore-blowing winds that prevented coastal upwelling and export production. © 2008 Elsevier B.V. All rights reserved.



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Article
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ISI/Scopus peer-reviewed
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Published
Eprint ID
18898
DOI https://www.doi.org/10.1016/j.epsl.2008.04.043

Cite as
Mohtadi, M. , Rossel, P. , Lange, C. B. , Pantoja, S. , Böning, P. , Repeta, D. J. , Grunwald, M. , Lamy, F. , Hebbeln, D. and Brumsack, H. J. (2008): Deglacial pattern of circulation and marine productivity in the upwelling region off central-south Chile , Earth and Planetary Science Letters, 272 (1-2), pp. 221-230 . doi: https://www.doi.org/10.1016/j.epsl.2008.04.043


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