Journal
NATURE GEOSCIENCE
Volume 1, Issue 5, Pages 329-334Publisher
NATURE PUBLISHING GROUP
DOI: 10.1038/ngeo179
Keywords
-
Categories
Funding
- Division Of Ocean Sciences
- Directorate For Geosciences [0751757] Funding Source: National Science Foundation
Ask authors/readers for more resources
In the largest global cooling event of the Cenozoic Era, between 33.8 and 33.5 Myr ago, warm, high-CO2 conditions gave way to the variable 'icehouse' climates that prevail today. Despite intense study, the history of cooling versus ice-sheet growth and sea-level fall reconstructed from oxygen isotope values in marine sediments at the transition has not been resolved. Here, we analyse oxygen isotopes and Mg/Ca ratios of benthic for aminifera, and integrate the results with the stratigraphic record of sea-level change across the Eocene-Oligocene transition from a continental-shelf site at Saint Stephens Quarry, Alabama. Comparisons with deep-sea (Sites 522 (South Atlantic) and 1218 (Pacific)) delta O-18 and Mg/Ca records enable us to reconstruct temperature, ice-volume and sea- level changes across the climate transition. Our records show that the transition occurred in at least three distinct steps, with an increasing influence of ice volume on the oxygen isotope record as the transition progressed. By the early Oligocene, ice sheets were similar to 25% larger than present. This growth was associated with a relative sea- level decrease of approximately 105 m, which equates to a 67m eustatic fall.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available