Middle Miocene Southern Ocean Cooling and Antarctic Cryosphere Expansion

Amelia E. Shevenell; James P. Kennett; David W. Lea

doi:10.1126/science.1100061

Middle Miocene Southern Ocean Cooling and Antarctic Cryosphere Expansion

Amelia E. Shevenell, James P. Kennett, David W. Lea

Research output: Contribution to journal › Article › peer-review

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 CO ₂ ( p CO ₂ ). Comparing SSTs and global carbon cycling proxies challenges the notion that episodic p CO ₂ 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.

Original language	American English
Journal	Science
Volume	305
DOIs	https://doi.org/10.1126/science.1100061
State	Published - Sep 1 2004
Externally published	Yes

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Life Sciences

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title = "Middle Miocene Southern Ocean Cooling and Antarctic Cryosphere Expansion",

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 CO 2 ( p CO 2 ). Comparing SSTs and global carbon cycling proxies challenges the notion that episodic p CO 2 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.",

author = "Shevenell, \{Amelia E.\} and Kennett, \{James P.\} and Lea, \{David W.\}",

year = "2004",

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doi = "10.1126/science.1100061",

language = "American English",

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T1 - Middle Miocene Southern Ocean Cooling and Antarctic Cryosphere Expansion

AU - Shevenell, Amelia E.

AU - Kennett, James P.

AU - Lea, David W.

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N2 - 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 CO 2 ( p CO 2 ). Comparing SSTs and global carbon cycling proxies challenges the notion that episodic p CO 2 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.

AB - 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 CO 2 ( p CO 2 ). Comparing SSTs and global carbon cycling proxies challenges the notion that episodic p CO 2 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.

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

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DO - 10.1126/science.1100061

M3 - Article

C2 - 15375266

VL - 305

JO - Science

JF - Science

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Middle Miocene Southern Ocean Cooling and Antarctic Cryosphere Expansion

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