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- Title
Middle Miocene Southern Ocean cooling and Antarctic cryosphere expansion.
- Authors
Shevenell, Amelia E; Kennett, James P; Lea, David W
- Abstract
Magnesium/calcium data from Southern Ocean planktonic foraminifera demonstrate that high-latitude (approximately 55 degrees S) southwest Pacific sea surface temperatures (SSTs) cooled 6 degrees to 7 degrees C during the middle Miocene climate transition (14.2 to 13.8 million years ago). Stepwise surface cooling is paced by eccentricity forcing and precedes Antarctic cryosphere expansion by approximately 60 thousand years, suggesting the involvement of additional feedbacks during this interval of inferred low-atmospheric partial pressure of CO2 (pCO2). Comparing SSTs and global carbon cycling proxies challenges the notion that episodic pCO2 drawdown drove this major Cenozoic climate transition. SST, salinity, and ice-volume trends suggest instead that orbitally paced ocean circulation changes altered meridional heat/vapor transport, triggering ice growth and global cooling.
- Publication
Science (New York, N.Y.), 2004, Vol 305, Issue 5691, p1766
- ISSN
1095-9203
- Publication type
Journal Article
- DOI
10.1126/science.1100061