Evidence for late Oligocene establishment of the Antarctic Circumpolar Current.

Pfuhl, H. A. and McCave, I. N. (2005) Evidence for late Oligocene establishment of the Antarctic Circumpolar Current. Earth and Planetary Science Letters, 235 (3-4). pp. 715-728. ISSN 0012-821X DOI 10.1016/j.epsl.2005.04.025

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Abstract

Removal of the last impediment to circum-Antarctic flow – opening of the Drake Passage between Antarctica and South America – is essential to establishment of the ACC, and has been placed in both the earliest Oligocene and earliest Miocene on the basis of paleomagnetic reconstructions. The Tasman Gateway between Antarctica and Tasmania notably deepened following ~33.5 Ma. Completion of the ACC circuit has been seen as the key to major growth of the East Antarctic Ice Sheet by thermal isolation of the continent. An alternative argument attributes ice sheet growth to changes in atmospheric pCO2. We present evidence on current strength and water-mass properties suggesting a clear increase in flow speed and homogeneity of Southern Ocean water masses in the latest Oligocene after about 23.95 Ma, marking establishment of the ACC, attributable to deep opening of Drake Passage. The Mi-1 glaciation may be a consequence. Establishment of a permanent, low altitude ice sheet does not appear to take place prior to mid-Miocene cooling.

Item Type: Article
Uncontrolled Keywords: 2005 AREP IA48 2005 P
Subjects: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Divisions: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Journal or Publication Title: Earth and Planetary Science Letters
Volume: 235
Page Range: pp. 715-728
Identification Number: 10.1016/j.epsl.2005.04.025
Depositing User: Sarah Humbert
Date Deposited: 20 Aug 2010 10:50
Last Modified: 23 Jul 2013 09:59
URI: http://eprints.esc.cam.ac.uk/id/eprint/1776

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