Extreme warming of tropical waters during the Paleocene-Eocene Thermal Maximum

Aze, T., Pearson, P.N., Dickson, A.J., Badger, M.P.S., Bown, P.R., Pancost, R.D., Gibbs, S.J., Huber, B.T., Leng, M.J., Coe, A.L., Cohen, A.S. and Foster, G.L. (2014) Extreme warming of tropical waters during the Paleocene-Eocene Thermal Maximum. Geology, 42 (9), 739-742. (doi:10.1130/G35637.1).

Abstract

The Paleocene–Eocene Thermal Maximum (PETM), ca. 56 Ma, was a major global environmental perturbation attributed to a rapid rise in the concentration of greenhouse gases in the atmosphere. Geochemical records of tropical sea-surface temperatures (SSTs) from the PETM are rare and are typically affected by post-depositional diagenesis. To circumvent this issue, we have analyzed oxygen isotope ratios (δ¹⁸O) of single specimens of exceptionally well-preserved planktonic foraminifera from the PETM in Tanzania (~19°S paleolatitude), which yield extremely low δ¹⁸O, down to <–5‰. After accounting for changes in seawater chemistry and pH, we estimate from the foraminifer δ¹⁸O that tropical SSTs rose by >3 °C during the PETM and may have exceeded 40 °C. Calcareous plankton are absent from a large part of the Tanzania PETM record; extreme environmental change may have temporarily caused foraminiferal exclusion.

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Contributors

Author: G.L. Foster

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