North Atlantic Deepwater Temperature Change During Late Pliocene and Late Quaternary Climatic Cycles
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- Gary S. Dwyer
- G. S. Dwyer and P. A. Baker, Department of Geology, Duke University, Durham, NC 27708, USA.
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- Thomas M. Cronin
- T. M. Cronin, U.S. Geological Survey, Branch of Paleontology and Stratigraphy, Mail Stop 970 National Center, Reston, VA 22092, USA.
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- Paul A. Baker
- G. S. Dwyer and P. A. Baker, Department of Geology, Duke University, Durham, NC 27708, USA.
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- Maureen E. Raymo
- M. E. Raymo, Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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- Jeffrey S. Buzas
- J. S. Buzas, Department of Mathematics and Statistics, University of Vermont, Burlington, VT 05051, USA.
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- Thierry Corrège
- T. Corrège, Départment de Géologie et Océanographie, Université de Bordeaux I, Avenue des Facultés, Bordeaux, France.
書誌事項
- 公開日
- 1995-11-24
- DOI
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- 10.1126/science.270.5240.1347
- 公開者
- American Association for the Advancement of Science (AAAS)
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説明
<jats:p>Variations in the ratio of magnesium to calcium (Mg/Ca) in fossil ostracodes from Deep Sea Drilling Project Site 607 in the deep North Atlantic show that the change in bottom water temperature during late Pliocene 41,000-year obliquity cycles averaged 1.5°C between 3.2 and 2.8 million years ago (Ma) and increased to 2.3°C between 2.8 and 2.3 Ma, coincidentally with the intensification of Northern Hemisphere glaciation. During the last two 100,000-year glacial-to-interglacial climatic cycles of the Quaternary, bottom water temperatures changed by 4.5°C. These results show that glacial deepwater cooling has intensified since 3.2 Ma, most likely as the result of progressively diminished deepwater production in the North Atlantic and of the greater influence of Antarctic bottom water in the North Atlantic during glacial periods. The ostracode Mg/Ca data also allow the direct determination of the temperature component of the benthic foraminiferal oxygen isotope record from Site 607, as well as derivation of a hypothetical sea-level curve for the late Pliocene and late Quaternary. The effects of dissolution on the Mg/Ca ratios of ostracode shells appear to have been minimal.</jats:p>
収録刊行物
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- Science
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Science 270 (5240), 1347-1351, 1995-11-24
American Association for the Advancement of Science (AAAS)