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dc.contributor.advisorMacLeod, Kenneth G., 1964-eng
dc.contributor.authorQuinton, Pageeng
dc.date.issued2012eng
dc.date.submitted2012 Springeng
dc.descriptionTitle from PDF of title page (University of Missouri--Columbia, viewed on September 18, 2012).eng
dc.descriptionThe entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.eng
dc.descriptionThesis advisor: Dr. Kenneth G. MacLeodeng
dc.descriptionIncludes bibliographical references.eng
dc.descriptionM.S. University of Missouri--Columbia 2012.eng
dc.descriptionDissertations, Academic -- University of Missouri--Columbia -- Geological sciences.eng
dc.description"May 2012"eng
dc.description.abstract[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] To test competing interpretations of Late Ordovician climate evolution, sea surface temperatures were estimated from oxygen isotope ratios of single-species separates of conodont apatite from the mid-continent region of the United States. A major glaciation occurs at the end of the Ordovician, but disagreement exists over the timing of this event. This controversy stems from a lack of good constraints on the temperature history during this period and relatively poor age control on evidence of possible Katian (454-444 Ma) glaciation. The end Ordovician glacial episode is accompanied by the 2nd largest mass extinction event of the Phanerozoic and marks a dramatic transition out of the 'greenhouse' conditions dominating the Ordovician. Results from the sampled ~9 my long interval indicate significant fluctuations around a δ18OVSMOW mean of 18.9‰, but no general trends during much of the Katian (454-444 Ma). A gradual warming trend began in the mid-Katian (~449 Ma), though, and continued through the late Katian. Depending on assumptions about δ18O values of Late Ordovician sea water, the estimated warming ranges from 0.7 to 3.2°C. These observations indicate that cooling and glaciation did not begin until the Hirnantian and are consistent with predictions for mid-Katian warming (the Boda event).eng
dc.format.extentvi, 77 pageseng
dc.identifier.urihttp://hdl.handle.net/10355/15397
dc.languageEnglisheng
dc.publisherUniversity of Missouri--Columbiaeng
dc.relation.ispartofcollectionUniversity of Missouri--Columbia. Graduate School. Theses and Dissertationseng
dc.rightsAccess is limited to the campuses of the University of Missouri.eng
dc.subjectLate Ordovician glaciationeng
dc.subjectconodont paleothermometryeng
dc.subjectoxygen isotopeseng
dc.titleOxygen isotopes from conodonts of the mid-continent, US: implications for Late Ordovician climate evolutioneng
dc.typeThesiseng
thesis.degree.disciplineGeological sciences (MU)eng
thesis.degree.grantorUniversity of Missouri--Columbiaeng
thesis.degree.levelMasterseng
thesis.degree.nameM.S.eng


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