Extreme warming of tropical waters during the Paleocene-Eocene Thermal Maximum
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 affect...
Published in: | Geology |
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Main Authors: | , , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Geological Society of America
2014
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Subjects: | |
Online Access: | http://nora.nerc.ac.uk/id/eprint/508323/ https://nora.nerc.ac.uk/id/eprint/508323/1/739.full.pdf https://doi.org/10.1130/G35637.1 |
Summary: | 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 (d18O) of single specimens of exceptionally well-preserved planktonic foraminifera from the PETM in Tanzania (~19°S paleolatitude), which yield extremely low d18O, down to <–5‰. After accounting for changes in seawater chemistry and pH, we estimate from the foraminifer d18O 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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