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dc.contributor.advisorThomas, Deborah J.
dc.creatorWoodard, Stella C.
dc.date.accessioned2012-07-16T15:56:56Z
dc.date.accessioned2012-07-16T20:32:33Z
dc.date.available2012-07-16T15:56:56Z
dc.date.available2012-07-16T20:32:33Z
dc.date.created2011-05
dc.date.issued2012-07-16
dc.date.submittedMay 2011
dc.identifier.urihttp://hdl.handle.net/1969.1/ETD-TAMU-2011-05-9279
dc.description.abstractGlobal climate is controlled by two factors, the amount of heat energy received from the sun (solar insolation) and the way that heat is distributed Earth's surface. Solar insolation varies on timescales of 10s to 100s of thousands of years due to changes in the path of Earth's orbit about the sun (Milankovitch cycles). Earth's internal boundary conditions, such as paleogeography, the presence/absence of polar icecaps, atmospheric/oceanic chemistry and sea level, provide distribution and feedback mechanisms for the incoming heat. Variations in these internal boundary conditions may happen abruptly or, as in the case of plate tectonics, take millions of years. We use geochemical and sedimentological techniques to investigate the response of ocean chemistry, regional aridity and atmospheric and oceanic circulation patterns to climate change during both greenhouse and icehouse climates. To explore the connection between orbitally-forced changes in solar insolation, continental aridity and wind, we generated a high-resolution dust record for ~58 Myr old deep-sea sediments from Shatsky Rise. Our data provide the first evidence of a correlation between dust flux to the deep sea and orbital cycles during the Early Paleogene, indicating dust supply (regional aridity) responded to orbital forcing during the last major interval of greenhouse climate. The change in dust flux was comparable to that during icehouse climates implying subtle variations in solar insolation have a similar impact on climate during intervals of over-all warmth as they do during glacial-interglacial states. The Carboniferous Period (359-299 Ma) marks a critical time in Earth's history when a series of tectonic and biological events caused a shift in the mean climate state from a global "greenhouse" to an "icehouse". Geochemical records extracted from sedimentary rocks deposited in shallow epicontinental seaways are increasingly being used to infer relationships between tectonism, carbon cycling and climate and therefore are assumed to reflect global ocean processes. We analyzed radiogenic isotopes in biogenic apatite along a North American transect to constrain the degree of geochemical coupling between the epicontinental seas and the open ocean. Our results argue strongly for decoupling of North American seaways from the open ocean by latest Mississippian time.en
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.subjectorbital cycles (Milankovitch)en
dc.subjecteolian dusten
dc.subjectgreenhouse climateen
dc.subjectPaleogeneen
dc.subjecticehouse climateen
dc.subjectCarboniferousen
dc.subjectNd isotopesen
dc.subjectSr isotopesen
dc.subjectTh-232en
dc.subjectcrustal He-4en
dc.subjectpaleoceanographyen
dc.subjectpaleoclimateen
dc.subjectNorth American epicontinental seaen
dc.subjectShatsky Riseen
dc.subjectPacific Oceanen
dc.subjectODP Site 1209en
dc.titleOceanic and atmospheric response to climate change over varying geologic timescalesen
dc.typeThesisen
thesis.degree.departmentOceanographyen
thesis.degree.disciplineOceanographyen
thesis.degree.grantorTexas A&M Universityen
thesis.degree.nameDoctor of Philosophyen
thesis.degree.levelDoctoralen
dc.contributor.committeeMemberGrossman, Ethan
dc.contributor.committeeMemberSlowey, Niall
dc.contributor.committeeMemberLyle, Mitchell
dc.contributor.committeeMemberMarcantonio, Franco
dc.type.genrethesisen
dc.type.materialtexten


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