1. Antarctic role in Northern Hemisphere glaciation.
- Author
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Woodard, Stella C., Rosenthal, Yair, Miller, Kenneth G., Wright, James D., Chiu, Beverly K., and Lawrence, Kira T.
- Subjects
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PLIOCENE paleoclimatology , *PLIOCENE paleoecology , *OCEAN temperature , *DEEP-sea temperature , *TEMPERATURE lapse rate , *GLACIAL climates - Abstract
Earth's climate underwent a major transition from the warmth of the late Pliocene, when global surface temperatures were ~2° to 3°C higher than today, to extensive Northern Hemisphere glaciation (NHG) ~2.73 million years ago (Ma).We show that North Pacific deep waters were substantially colder (4°C) and probably fresher than the North Atlantic Deep Water before the intensification of NHG. At ~2.73 Ma, the Atlantic-Pacific temperature gradient was reduced to <1°C, suggesting the initiation of stronger heat transfer from the North Atlantic to the deep Pacific. We posit that increased glaciation of Antarctica, deduced from the 21 ± 10-meter sea-level fall from 3.15 to 2.75 Ma, and the development of a strong polar halocline fundamentally altered deep ocean circulation, which enhanced interhemispheric heat and salt transport, thereby contributing to NHG. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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