Terrestrial Alteration of CM2 Chondritic Carbonates in a Suite of Paired Antarctic Meteorites.

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dc.contributor.advisorFarquhar, Jamesen_US
dc.contributor.authorTyra, Mark Anthonyen_US
dc.contributor.departmentGeologyen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2005-08-03T15:31:35Z
dc.date.available2005-08-03T15:31:35Z
dc.date.issued2005-06-01en_US
dc.description.abstractThe δ18O, δ17O, δ13C, and δ14C compositions of carbonate grains were measured from paired Antarctic CM2 chondrites (EET96006, EET96016, EET96017, and EET96019). Oxygen isotopic compositions reveal both terrestrial and extraterrestrial carbonate sources. Bulk δ13C and δ14C measurements suggest at least two terrestrial carbonate components: 1) carbonate derived from equilibration of atmospheric CO2 with silicates during weathering reactions, and 2) carbonate derived from a second undefined source. Oxygen and carbon isotope data suggest that silicate weathering reactions drove oxygen isotopic composition of Antarctic water away from the terrestrial fractionation line (TFL) (D17O < 3.6). Further oxygen isotopic compositional constraints were placed by Secondary Ionization Mass Spectrometry (SIMS) of in-situ carbonates. We suggest three sources for meteoritic carbonate: 1) primary calcite formed in the presence of evolving planetesimal water and 2) secondary calcite derived from alkalinity laden terrestrial water and 3) alkalinity formed as the result of weathering of meteoritic silicates.en_US
dc.format.extent6612264 bytes
dc.format.mimetypeapplication/pdf
dc.identifier.urihttp://hdl.handle.net/1903/2672
dc.language.isoen_US
dc.subject.pqcontrolledGeochemistryen_US
dc.subject.pqcontrolledGeologyen_US
dc.subject.pqcontrolledChemistry, Physicalen_US
dc.subject.pquncontrolledAntarctic meteoritesen_US
dc.subject.pquncontrolledCMen_US
dc.subject.pquncontrolledcarbonateen_US
dc.subject.pquncontrolledweatheringen_US
dc.subject.pquncontrolledC-14en_US
dc.subject.pquncontrolledisotope geochemistryen_US
dc.titleTerrestrial Alteration of CM2 Chondritic Carbonates in a Suite of Paired Antarctic Meteorites.en_US
dc.typeThesisen_US

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