Petrogenesis of the phase 1 gabbro-diorite of the Miocene Mt Perkins Pluton, northwest Arizona: Implications for the role of mantle-derived mafic magmas in calc-alkaline magma evolution

Mafic magmas play a significant role in the evolution of calc-alkaline magma systems in convergent and extensional environments. The Miocene Mt. Perkins pluton, northwestern Arizona, was emplaced as a series of four discrete magma pulses into a country rock of Precambrian orthogneiss. Phase 1 is a gabbro-diorite containing four rock groups: olivine-clinopyroxene cumulates, hornblende-plagioclase cumulates, homblende gabbro, and quartz diorite. Stage one of phases 2 and 3 evolved by a process of fractional crystallization of an asthenospheric mantle derived mafic magma and magma mixing with an upper crustal granitic magma. Phase 1 magmas evolved by fractional crystallization (required by the presence of cumulates) of an asthenospheric mantle derived mafic magma and contamination by an asthenospheric-lithospheric mantle derived basaltic magma at depth and the orthogneiss at emplacement level. Phases 1, 2, and 3 share a common asthenospheric mantle derived magma. Mafic mantle derived melts are generated continuously throughout magma system evolution.

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

1998

Author dc:creator

• Danielson, Lisa Renee

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/

Identifier

https://oasis.library.unlv.edu/rtds/913

OAI identifier oai:identifier

oai:oasis.library.unlv.edu:rtds-1912