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Age, composition, and origin of the lower continental crust, northern Tanzania

dc.contributor.advisorRudnick, Roberta Len_US
dc.contributor.authorMansur, Adam T.en_US
dc.date.accessioned2009-03-24T05:39:08Z
dc.date.available2009-03-24T05:39:08Z
dc.date.issued2008en_US
dc.identifier.urihttp://hdl.handle.net/1903/8993
dc.description.abstractGranulite xenoliths from the East African rift in Tanzania sample the lower continental crust beneath both the stable Tanzanian craton and the adjacent, polymetamorphic Mozambique belt. Protoliths of surface rocks in both terranes formed 2.8 to 2.6 Ga ago, but only the Mozambique belt underwent significant post-Archean metamorphism. Most granulite xenoliths represent mafic magmas formed in a convergent margin at ca. 2660 Ma that were subsequently metamorphosed at lower crustal conditions. However, a small number of xenoliths are more similar to intraplate magmas, suggesting that at least two episodes of lower crustal growth occurred during the Archean. No post-Archean additions to the crust were detected beneath either terrane, but xenoliths from the Mozambique belt record high P-T conditions, suggesting equilibration at the base of orogenically thickened crust. By contrast, xenoliths from beneath the craton equilibrated under conditions typical of unthickened continental crust.en_US
dc.format.extent70712955 bytes
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.titleAge, composition, and origin of the lower continental crust, northern Tanzaniaen_US
dc.typeThesisen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.contributor.departmentGeologyen_US
dc.subject.pqcontrolledGeologyen_US
dc.subject.pqcontrolledGeochemistryen_US
dc.subject.pquncontrolledArcheanen_US
dc.subject.pquncontrolledComposition of the continental crusten_US
dc.subject.pquncontrolledMajor and trace element geochemistryen_US
dc.subject.pquncontrolledMetamorphic petrologyen_US
dc.subject.pquncontrolledRadiogenic isotope geochemistryen_US


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