Middle Miocene Southern Ocean Cooling and Antarctic Cryosphere Expansion

Authors

Amelia E. Shevenell, University of California, Santa BarbaraFollow
James P. Kennett, University of California, Santa Barbara
David W. Lea, University of California, Santa Barbara

Document Type

Article

Publication Date

9-2004

Digital Object Identifier (DOI)

https://doi.org/10.1126/science.1100061

Abstract

Magnesium/calcium data from Southern Ocean planktonic foraminifera demonstrate that high-latitude (∼55°S) southwest Pacific sea surface temperatures (SSTs) cooled 6° to 7°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 ∼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.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

Science, v. 305, issue 5691, p. 1766-1770

Scholar Commons Citation

Shevenell, Amelia E.; Kennett, James P.; and Lea, David W., "Middle Miocene Southern Ocean Cooling and Antarctic Cryosphere Expansion" (2004). Marine Science Faculty Publications. 583.
https://digitalcommons.usf.edu/msc_facpub/583