Petrogenetic study of the Porcupine Lake mafic intrusive complex, Trinity terrane, northern California

The Early Devonian (404 +/- 3 Ma) Porcupine Lake mafic intrusive complex of the Trinity terrane consists primarily of ultramafic-mafic plutonic and dike lithologies. The plutonic rock forms steep intrusive contacts with adjacent Ordovician peridotite, and consists of basal layered peridotite, cumulate clinopyroxenite, and isotropic gabbro. East-west trending mafic-to-felsic aphanitic dikes intrude the plutonic rocks, with high dike concentrations (>80%) in the southern portion of the complex; Gabbro and mafic dikes display subduction-related enrichment of light-ion lithophile elements and high degrees of depletion of high-field strength elements (Nb, Ta ≅ 0.1 NMORB). Trace element mixing models indicate gabbro and mafic dikes are derived from a residual mantle source with enrichment by small amounts of slab-derived aqueous fluids and pelagic sediments. Mafic dikes are also enriched by fertile MORB (asthenospheric) mantle. Subduction zone enrichment of a depleted mantle source suggests the Porcupine Lake mafic intrusive complex formed in a forearc tectonic setting.

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Geoscience

Grantor dc:publisher

University of Nevada, Las Vegas

Year

2000

Author dc:creator

• Muller, Edward Robert

Contributors dc:contributor

• Rodney V. Metcalf

Statement dc:rights

• IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

Language dc:language

English

Identifier

https://oasis.library.unlv.edu/rtds/1171

OAI identifier oai:identifier

oai:oasis.library.unlv.edu:rtds-2170