The origin of the Wilson Ridge pluton and its enclaves, northwestern Arizona: Implications for the generation of a calc-alkaline intermediate pluton in an extensional environment
The Wilson Ridge pluton is an epizonal calc-alkaline pluton that formed about 13.5 Ma during a period of mid-Miocene extension. The pluton was passively emplaced into a 1.7 to 1.8 Ga Precambrian crystalline terrain. High-angle normal faulting resulted in a series of horsts and grabens that provide windows into deep structural levels of the pluton; The Wilson Ridge pluton is composed of the Teakettle Pass suite, comprised of foliated monzodiorite and quartz monzodiorite, and unfoliated quartz monzonite; and the older Horsethief Canyon diorite; Intermediate rocks of the Teakettle Pass suite contain abundant basalt and diorite enclaves; Field evidence and major and trace element models suggests that the intermediate rocks of the pluton were produced by the commingling of a large volume of mafic magma with a smaller volume of felsic magma (a mafic-felsic ratio of about 70:30) as well as fractional crystallization. Similar open system processes may be responsible for the production of calc-alkaline intermediate rocks in other parts of the Great Basin. (Abstract shortened with permission of author.).
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