Lithospheric magmatism in southern Colorado and northern New Mexico.

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dc.contributor.advisorParker, Donnie Franklin, 1948-
dc.contributor.authorWegert, Daniel James.
dc.contributor.departmentGeology.en_US
dc.contributor.otherDavid Edlin.en_US
dc.contributor.otherMinghua Ren.en_US
dc.contributor.schoolsBaylor University. Dept. of Geology.en_US
dc.date.accessioned2014-09-05T14:26:07Z
dc.date.accessioned2017-04-07T19:35:15Z
dc.date.available2014-09-05T14:26:07Z
dc.date.available2017-04-07T19:35:15Z
dc.date.copyright2014-08
dc.date.issued2014-09-05
dc.description.abstractThis dissertation looks at the formation of three different volcanic centers throughout southern Colorado and northern New Mexico to evaluate potential sources for their subduction-like trace element signatures. These subduction signatures are found in volcanic rocks formed well away from concurrent subduction and are, in many cases, rift related. The Laramide-age McDermott Formation is a lahar deposit deposited into the San Juan Basin formed through melting of Proterozoic subduction-modified lithospheric mantle. Near zero εNdt values (-1.94 and 0.47) rule out a crustal source for these magmas, while trace element ratios suggest a subduction-modified continental lithosphere source. Geochemical analyses suggest a possible relationship to the La Plata Mountains intrusive complex, though weathering and sericitization have made confirming this hypothesis impossible. The Nathrop domes are crustal melts formed due to partial melting associated with crustal extension along the Arkansas Valley Graben segment of the Rio Grande Rift. εNdt values (-10.1, Bald Mountain and -13.9, Precambrian granite) suggest that the magmas ancestral to those of the Nathrop Domes were largely the result of partial melting of Precambrian crustal rock. These crustal melts then evolved through protracted crystal fractionation of observed phenocrysts, yielding the large enrichment/depletion patterns observed in incompatible element diagrams. The Raton-Clayton volcanic field lies on the Jemez Lineament, on the eastern flank of the Rio Grande Rift. The Jemez Lineament coincides with the ancient Proterozoic boundary between the Matzatzal and Yavapai terranes, which have been interpreted as accreted arc complexes. The subduction signature present in the RCVF lavas is attributed to modification during this event. The RCVF magmas show evidence that both assimilation and fractional crystallization played significant roles in their evolution. εNd values for all samples indicate derivation from lithospheric mantle. Olivine back-calculation results were used to determine that magmas ancestral to Raton-Clayton basalts were formed between 50 and 217 km inside the Earth.en_US
dc.description.degreePh.D.en_US
dc.identifier.citationWegert, D., Parker, D. F. "Petrogenesis of the McDermott Formation trachyandesite, San Juan Basin, Colorado and New Mexico." Rocky Mountain geology 46, 2 (2011): 183-196.en_US
dc.identifier.citationWegert, D., Parker, D. F., Ren, M. "The Nathrop Domes, Colorado : geochemistry and petrogenesis of a topaz rhyolite." Rocky Mountain geology 48, 1 (2013): 1-14.en_US
dc.identifier.urihttp://hdl.handle.net/2104/9196
dc.language.isoen_USen_US
dc.publisheren
dc.rightsBaylor University 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. Contact librarywebmaster@baylor.edu for inquiries about permission.en_US
dc.rights.accessrightsWorldwide access.en_US
dc.rights.accessrightsAccess changed 1/27/17.
dc.subjectRaton-Clayton volcanic field.en_US
dc.subjectNathrop Domes.en_US
dc.subjectMcDermott Formation.en_US
dc.subjectRio Grande Rift.en_US
dc.subjectColorado Mineral Belt.en_US
dc.subjectLa Plata Mountains.en_US
dc.subjectSan Juan Basin.en_US
dc.subjectPetrogenesis.en_US
dc.subjectRuby Mountain.en_US
dc.subjectJemez Lineament.en_US
dc.subjectPeraluminous rhyolite.en_US
dc.titleLithospheric magmatism in southern Colorado and northern New Mexico.en_US
dc.typeThesisen_US

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