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1999

Tectonics and Structure

California

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Full-Text Articles in Earth Sciences

Geochemistry And Petrogenesis Of The Bonanza King Mafic Intrusive Complex, Trinity Terrane Ophiolite, California, Keith R. Willse May 1999

Geochemistry And Petrogenesis Of The Bonanza King Mafic Intrusive Complex, Trinity Terrane Ophiolite, California, Keith R. Willse

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Bonanza King mafic intrusive complex (MIC) (>25 km2) of the Trinity terrane ophiolite, northern California, consists of cogenetic plutonic and dike lithologies. Steep intrusive contacts exist between cumulate pyroxenite, isotropic gabbro, and peridotite country rock. Near vertical east-west trending, bimodal dikes intruded gabbro and are centered within the complex. Geochemical modeling indicates taht accumulation/fractionation of a gabbroic parental magma produced lithologic trends of cumulate pyroxenite and fractionated gabbro and dike lithologies. Similarities between all lithologies suggest cogenetic formation of all the elements of the Bonanza King MIC during the Late Silurian (431 +/- 3).

Parental magma …