Middle Eocene regional climate instability: Evidence from the western North Atlantic
- 1Department of Geology and Geophysics, University of Edinburgh, Grant Institute, West Mains Road, Edinburgh EH9 3JW, UK
Abstract
High-resolution (∼3 k.y.) δ18O records from middle Eocene mixed-layer dwelling planktonic foraminifera from the western North Atlantic show pronounced (>1‰) variability. The magnitude of change is greater than that seen in open-ocean Pleistocene records, but could not have been caused by ice-volume and/or sea-level fluctuations. Instead, the oxygen isotope shifts resulted primarily from large oscillations in sea-surface temperatures and indicate that the regional paleoceanography of the middle Eocene western North Atlantic was not consistently warm or stable. The large shifts in sea-surface temperatures could reflect variations in the position of the Gulf Stream relative to Blake Nose or variations in upwelling intensity.
Footnotes
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↵*E-mail addresses: Wade—bwadeglg.ed.ac.uk; Kroon—Kroogeo.vu.nl. Present address: Kroon—Faculty of Earth Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, Netherlands
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↵GSA Data Repository item 2002119, Oxygen isotope data from Site 1052, is available from Documents Secretary, GSA, P.O. Box 9140, Boulder, CO 80301-9140, editinggeosociety.org, or at www.geosociety.org/pubs/ft2002.htm.
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- Accepted July 29, 2002.
- Received April 5, 2002.
- Revision received July 26, 2002.
- Geological Society of America
