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Construction, Emplacement, And Geochemical Evolution Of Deep-Crustal Intrusions: Tenpeak And Dirtyface Plutons, North Cascades, Western North America, Robert B. Miller, Susan M. Debari, Scott R. Paterson

Geology Faculty Publications

Deep plutonic systems represent an important link between lower-crustal melt-generation sites and higher-level regions of magma accumulation, but models for these systems are limited by the relative scarcity of exposed weakly deformed, deep-crustal plutons. Exceptions include the ca. 92.3–89.7 Ma, dominantly tonalitic Tenpeak pluton and the smaller, nearby ca. 91 Ma Dirtyface pluton of the North Cascades (western North America), which represent deeply exposed crustal levels (∼25–35 km) of a Cordilleran arc. Initial subduction-driven magmatism in the Tenpeak pluton was marked by co-magmatic hydrous mafic and felsic magmas, which formed gabbro, diorite, tonalite, and hornblendite within a heterogeneous mafic complex. …