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Hot summers in the Bighorn Basin during the early Paleogene

Kathryn E. Snell, Bridget L. Thrasher, John M. Eiler, Paul L. Koch, Lisa C. Sloan and Neil J. Tabor
Hot summers in the Bighorn Basin during the early Paleogene
Geology (Boulder) (October 2012) 41 (1): 55-58


During the early Paleogene, climate in continental interiors is thought to have been warmer and more equable than today, but estimates of seasonal temperature variations during this period are limited. Global and regional climate models of the Paleogene predict cooler temperatures for continental interiors than are implied by proxy data and predict a seasonal range of temperature that is similar to today. Here, we present a record of summer temperatures derived from carbonate clumped isotope thermometry of paleosol carbonates from Paleogene deposits in the Bighorn Basin, Wyoming (United States). Our summer temperature estimates are approximately 18 degrees C greater than mean annual temperature estimated from analysis of fossil leaves. When coupled, these two records yield a seasonal range of temperature similar to that in the region today, with winter temperatures that are near freezing. These data are consistent with our high-resolution climate model output for the Early Eocene in the Bighorn Basin. We suggest that temperatures in continental interiors during the early Paleogene greenhouse were warmer in all seasons, but not more equable than today. If generally true, this removes one of the long-standing paradoxes in our understanding of terrestrial climate dynamics under greenhouse conditions.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 41
Serial Issue: 1
Title: Hot summers in the Bighorn Basin during the early Paleogene
Affiliation: University of California at Santa Cruz, Earth and Planetary Sciences Department, Santa Cruz, CA, United States
Pages: 55-58
Published: 20121019
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 26
Accession Number: 2012-101396
Categories: StratigraphyIsotope geochemistry
Document Type: Serial
Bibliographic Level: Analytic
Annotation: With GSA Data Repository Item 2013021
Illustration Description: illus. incl. sketch maps
N53°00'00" - N54°30'00", W90°00'00" - W87°30'00"
Secondary Affiliation: California Institute of Technology, USA, United StatesSouthern Methodist University, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201252
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