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Summer temperatures of late Eocene to early Oligocene freshwaters

Stephen T. Grimes, Jerry J. Hooker, Margaret E. Collinson and David P. Mattey
Summer temperatures of late Eocene to early Oligocene freshwaters
Geology (Boulder) (March 2005) 33 (3): 189-192


The marine foraminiferal isotope record displays a positive delta (super 18) O shift early in the Oligocene, which has been identified as the onset of the Antarctic Oi-1 glaciation. Reported here are the first oxygen isotope-derived summer paleotemperatures for continental freshwater in the Northern Hemisphere (Hampshire Basin, Isle of Wight, UK) leading up to and across this event. These paleotemperatures are derived from multiple paleoproxies (rodent tooth enamel, gastropod shells, charophyte gyrogonites, and fish otoliths) and are independent of freshwater evaporation effects and changes in ice volume. We conclude that a fluctuating mesothermal climate existed, but that there was no significant decrease in summer temperatures across the Oi-1 glaciation. This result is concordant with several other studies in suggesting that the majority of the isotopic shift in the marine realm across the Oi-1 glaciation is linked to changes in Antarctic ice volume and not to global temperature change. Our new approach has allowed us to derive numerical values for summer temperatures as well as to reconstruct relative temperature change across this key interval of the Eocene-Oligocene transition.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 33
Serial Issue: 3
Title: Summer temperatures of late Eocene to early Oligocene freshwaters
Affiliation: Royal Holloway University of London, Department of Geology, Egham, United Kingdom
Pages: 189-192
Published: 200503
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 24
Accession Number: 2005-030938
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Annotation: With GSA Data Repository Item 2005035
Illustration Description: strat. cols.
N50°40'00" - N50°45'00", W01°30'00" - W01°00'00"
Secondary Affiliation: Natural History Museum, Cromwell Road, London SW7 5BD, GBR, United Kingdom
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 200517
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