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Climate of the Past An interactive open-access journal of the European Geosciences Union
Clim. Past, 12, 837-847, 2016
https://doi.org/10.5194/cp-12-837-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
07 Apr 2016
Constraints on ocean circulation at the Paleocene–Eocene Thermal Maximum from neodymium isotopes
April N. Abbott1,a, Brian A. Haley1,2, Aradhna K. Tripati3,4, and Martin Frank2 1CEOAS, OSU, 104 CEOAS Admin. Bldg., Corvallis, OR 97209, USA
2GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstraße 1–3, 24148 Kiel, Germany
3Department of Earth and Space Sciences, Department of Atmospheric and Oceanic Sciences, and Institute of the Environment and Sustainability, University of California, Los Angeles, CA 90095, USA
4European Institute of Marine Sciences (IUEM), Université de Brest, UMR 6538, Domaines Océaniques, Rue Dumont D'Urville, Plouzané, France
anow at: Macquarie University, Department of Earth and Planetary Sciences, North Ryde, Sydney, NSW 2109, Australia
Abstract. Global warming during the Paleocene–Eocene Thermal Maximum (PETM)  ∼  55 million years ago (Ma) coincided with a massive release of carbon to the ocean–atmosphere system, as indicated by carbon isotopic data. Previous studies have argued for a role of changing ocean circulation, possibly as a trigger or response to climatic changes. We use neodymium (Nd) isotopic data to reconstruct short high-resolution records of deep-water circulation across the PETM. These records are derived by reductively leaching sediments from seven globally distributed sites to reconstruct past deep-ocean circulation across the PETM. The Nd data for the leachates are interpreted to be consistent with previous studies that have used fish teeth Nd isotopes and benthic foraminiferal δ13C to constrain regions of convection. There is some evidence from combining Nd isotope and δ13C records that the three major ocean basins may not have had substantial exchanges of deep waters. If the isotopic data are interpreted within this framework, then the observed pattern may be explained if the strength of overturning in each basin varied distinctly over the PETM, resulting in differences in deep-water aging gradients between basins. Results are consistent with published interpretations from proxy data and model simulations that suggest modulation of overturning circulation had an important role for initiation and recovery of the ocean–atmosphere system associated with the PETM.

Citation: Abbott, A. N., Haley, B. A., Tripati, A. K., and Frank, M.: Constraints on ocean circulation at the Paleocene–Eocene Thermal Maximum from neodymium isotopes, Clim. Past, 12, 837-847, https://doi.org/10.5194/cp-12-837-2016, 2016.
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Short summary
The Paleocene-Eocene Thermal Maximum (PETM) was a brief period when the Earth was in an extreme greenhouse state. We use neodymium isotopes to suggest that during this time deep-ocean circulation was distinct in each basin (North and South Atlanic, Southern, Pacific) with little exchange between. Moreover, the Pacific data show the most variability, suggesting this was a critical region possibly involved in both PETM triggering and remediation.
The Paleocene-Eocene Thermal Maximum (PETM) was a brief period when the Earth was in an extreme...
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