Sea surface temperature reconstruction for the middle Miocene Southern Ocean

• Main Authors: Shevenell, Amelia E, Kennett, James P, Lea, David W
• Format: Dataset
• Language: English
• Published: PANGAEA 2004
• Subjects: 189-1170A; 189-1171C; DRILL; Drilling/drill rig; Indian Ocean; Joides Resolution; Leg189; Ocean Drilling Program; ODP; South Pacific Ocean; Antarctic; Indian; Pacific; Southern Ocean; Antarc*; Planktonic foraminifera
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.772059; https://doi.org/10.1594/PANGAEA.772059

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.