Timing and Climatic Consequences of the Opening of Drake Passage

Age estimates for the opening of Drake Passage range from 49 to 17 million years ago (Ma), complicating interpretations of the relationship between ocean circulation and global cooling. Secular variations of neodymium isotope ratios at Agulhas Ridge (Southern Ocean, Atlantic sector) suggest an influ...

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Bibliographic Details
Published in:Science
Main Authors: Scher, Howie D., Martin, Ellen E.
Format: Article in Journal/Newspaper
Language:English
Published: American Association for the Advancement of Science (AAAS) 2006
Subjects:
Antarctic
Drake Passage
Pacific
Southern Ocean
Antarc*
Online Access:http://dx.doi.org/10.1126/science.1120044
https://www.science.org/doi/pdf/10.1126/science.1120044
Description
Summary:Age estimates for the opening of Drake Passage range from 49 to 17 million years ago (Ma), complicating interpretations of the relationship between ocean circulation and global cooling. Secular variations of neodymium isotope ratios at Agulhas Ridge (Southern Ocean, Atlantic sector) suggest an influx of shallow Pacific seawater approximately 41 Ma. The timing of this connection and the subsequent deepening of the passage coincide with increased biological productivity and abrupt climate reversals. Circulation/productivity linkages are proposed as a mechanism for declining atmospheric carbon dioxide. These results also indicate that Drake Passage opened before the Tasmanian Gateway, implying the late Eocene establishment of a complete circum-Antarctic pathway.

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