Paleoceanography. Antarctic role in Northern Hemisphere glaciation.

Autor: Woodard SC; Department of Marine and Coastal Sciences, Rutgers University, 71 Dudley Road, New Brunswick, NJ 08901, USA. woodard@marine.rutgers.edu., Rosenthal Y; Department of Marine and Coastal Sciences, Rutgers University, 71 Dudley Road, New Brunswick, NJ 08901, USA. Department of Earth and Planetary Sciences, Rutgers University, 610 Taylor Road, Piscataway, NJ 08845, USA., Miller KG; Department of Earth and Planetary Sciences, Rutgers University, 610 Taylor Road, Piscataway, NJ 08845, USA., Wright JD; Department of Earth and Planetary Sciences, Rutgers University, 610 Taylor Road, Piscataway, NJ 08845, USA., Chiu BK; Department of Earth and Planetary Sciences, Rutgers University, 610 Taylor Road, Piscataway, NJ 08845, USA., Lawrence KT; Department of Geology and Environmental Geosciences, Lafayette College, 730 High Street, Easton, PA 18042, USA.
Jazyk: angličtina
Zdroj: Science (New York, N.Y.) [Science] 2014 Nov 14; Vol. 346 (6211), pp. 847-51. Date of Electronic Publication: 2014 Oct 23.
DOI: 10.1126/science.1255586
Abstrakt: 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.
(Copyright © 2014, American Association for the Advancement of Science.)
Databáze: MEDLINE
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