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GEOREF RECORD

Did intense volcanism trigger the first Late Ordovician icehouse?

Werner Buggisch, Michael M. Joachimski, Oliver Lehnert, Stig M. Bergstrom, John E. Repetski and Gerald F. Webers
Did intense volcanism trigger the first Late Ordovician icehouse?
Geology (Boulder) (April 2010) 38 (4): 327-330

Abstract

Oxygen isotopes measured on Late Ordovician conodonts from Minnesota and Kentucky (United States) were studied to reconstruct the paleotemperature history during late Sandbian to Katian (Mohawkian-Cincinnatian) time. This time interval was characterized by intense volcanism, as shown by the prominent Deicke, Millbrig, and other K-bentonite beds. A prominent carbon isotope excursion (Guttenberg delta (super 13) C excursion, GICE) postdates the Millbrig volcanic eruptions, and has been interpreted to reflect a drawdown of atmospheric carbon dioxide and climatic cooling. The oxygen isotope record in conodont apatite contradicts this earlier interpretation. An increase in delta (super 18) O of 1.5 per mil (Vienna standard mean ocean water) just above the Deicke K-bentonite suggests an abrupt and short-lived cooling that possibly initiated a first short-term glacial episode well before the major Hirnantian glaciation. The decrease in delta (super 18) O immediately after the mega-eruptions indicates warming before the GICE, and no cooling is shown in the GICE interval. The coincidence of the Deicke mega-eruption with a cooling event suggests that this major volcanic event had a profound effect on Late Ordovician (late Mohawkian) climate.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 38
Serial Issue: 4
Title: Did intense volcanism trigger the first Late Ordovician icehouse?
Affiliation: Universitaet Erlangen Nuernberg, Geozentrum Nordbayern, Erlangen, Federal Republic of Germany
Pages: 327-330
Published: 201004
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 39
Accession Number: 2010-039398
Categories: StratigraphyIsotope geochemistry
Document Type: Serial
Bibliographic Level: Analytic
Annotation: With GSA Data Repository Item 2010087
Illustration Description: 1 table, charts
N36°30'00" - N39°10'00", W89°40'00" - W82°00'00"
N43°30'00" - N49°00'00", W97°10'00" - W89°45'00"
Secondary Affiliation: Ohio State University, USA, United StatesU. S. Geological Survey, USA, United StatesMacalester College, 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: 201022
Program Name: USGSOPNon-USGS publications with USGS authors
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