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Biogeochemical proxies for environmental and biotic conditions at the Permian-Triassic boundary

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dc.contributor.advisor Roger E. Summons. en_US
dc.contributor.author Hays, Lindsay Elizabeth en_US
dc.contributor.other Massachusetts Institute of Technology. Dept. of Earth, Atmospheric, and Planetary Sciences. en_US
dc.date.accessioned 2010-10-29T18:27:45Z
dc.date.available 2010-10-29T18:27:45Z
dc.date.copyright 2010 en_US
dc.date.issued 2010 en_US
dc.identifier.uri http://hdl.handle.net/1721.1/59738
dc.description Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2010. en_US
dc.description Cataloged from PDF version of thesis. en_US
dc.description Includes bibliographical references. en_US
dc.description.abstract The extinction at the Permian-Triassic boundary marked one of the most profound events of the Phanerozoic Eon. Although numerous hypotheses have been proposed, the trigger mechanism continues to be debated. This thesis intends to examine the impact of oceanic conditions on the extinction event by analyzing hydrocarbon biomarkers. Hydrocarbon biomarkers are chemical fossils in sedimentary rocks that serve as proxies to measure the conditions that prevailed during deposition. In this thesis, biomarkers for redox conditions, depositional environment, microbial community and potential age-related biomarkers have been measured and are reported from four sections that span the Permian-Triassic boundary. The first section, from the Peace River Basin in modern-day western Canada, was deposited on the eastern margin of the Panthalassic Ocean and samples conditions in this global water body. The second section is from Kap Stosch, Greenland, and was deposited on the southern margin of an epicontinental sea situated in the northwest of the supercontinent Pangaea. The Great Bank of Guizhou, China is the third section studied, and it is a carbonate platform deposited on the southern edge of one of the smaller continental blocks that formed the eastern margin of the Paleo-Tethys Ocean. The fourth section, for the Permian-Triassic boundary is from Meishan, China, the type section for this boundary, and was deposited on the western margin of another one of the continental blocks at the edge of the Paleo-Tethys Ocean. The biomarker evidence from these sections was measured in ratios, absolute abundances and for 613C isotopic values. This evidence points to global marine conditions dominated by bacterial inputs in which photic zone euxinia was prevalent for extended time periods. Additional findings from compound-specific isotope data suggest that at isolated intervals, the chemocine may have extended even closer to the surface. The timing of these intervals implies that ocean conditions may have affected the extinction itself. en_US
dc.description.statementofresponsibility by Lindsay Elizabeth Hays. en_US
dc.format.extent 287 p. en_US
dc.language.iso eng en_US
dc.publisher Massachusetts Institute of Technology en_US
dc.rights M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. en_US
dc.rights.uri http://dspace.mit.edu/handle/1721.1/7582 en_US
dc.subject Earth, Atmospheric, and Planetary Sciences. en_US
dc.title Biogeochemical proxies for environmental and biotic conditions at the Permian-Triassic boundary en_US
dc.type Thesis en_US
dc.description.degree Ph.D. en_US
dc.contributor.department Massachusetts Institute of Technology. Dept. of Earth, Atmospheric, and Planetary Sciences. en_US
dc.identifier.oclc 670426704 en_US


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