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dc.contributor.authorHamil, Arminda Brooke
dc.date.accessioned2014-03-04T21:01:52Z
dc.date.available2014-03-04T21:01:52Z
dc.date.issued2013-05
dc.identifier.otherhamil_arminda_b_201305_ms
dc.identifier.urihttp://purl.galileo.usg.edu/uga_etd/hamil_arminda_b_201305_ms
dc.identifier.urihttp://hdl.handle.net/10724/28750
dc.description.abstractThe Spanish Peaks Intrusive Complex, Colorado, is composed of compositionally diverse mid-Tertiary igneous rocks. The intrusive stocks of the Spanish Peaks are surrounded by a famous radial dike system as well as subparallel dikes and sills that include lamprophyres. Some of the lamprophyres are relatively sodic (Na2O>K2O) and others are relatively potassic (Na2O<K2O). The lamprophyres are approximately the same age (20-25 Ma; Miggins, 2002), providing a unique opportunity to study the nature of the sources of two highly distinct, contemporaneous alkaline magmas. McGregor (2010) hypothesized the two groups of lamprophyres formed from sequential melting of distinct phase assemblages in the same metasomatic vein. Distinct initial Sr ratios from this study disprove this hypothesis. I hypothesize that the two types of lamprophyres were sourced from separate groups of veins that formed from the same metasomatic event but have distinct phase assemblages because they crystallized at different depths in the upper mantle.
dc.languageeng
dc.publisheruga
dc.rightspublic
dc.subjectSpanish Peaks
dc.subjectalkaline rocks
dc.subjectlamprophyres
dc.subjectsodic rocks
dc.subjectpotassic rocks
dc.subjectSr analysis
dc.subjectmetasomatism
dc.subjectamphibole megacrysts
dc.titleMantle metasomatism and the generation of alkaline lamprophyres in the Spanish Peaks Intrusive Complex, south-central Colorado
dc.typeThesis
dc.description.degreeMS
dc.description.departmentGeology
dc.description.majorGeology
dc.description.advisorMichael Roden
dc.description.committeeMichael Roden
dc.description.committeeThomas Jordan
dc.description.committeeDouglas Crowe


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