Contemporaneous faulting likely stimulated these processes via further emplacing mafic magma into the upper crust and also by providing a mechanism that could drive magma mixing. SC silicic products vary physically, chemically, and isotopically according to geographic location and again, require the presence of numerous magmatic systems throughout the >2-Ma duration of the SC. The physical, chemical, and isotopic characteristics of SC silicic units are also consistent with their derivation via crustal anatexis of local Cretaceous granitoid upper crust, as well as the potential incorporation of Triassic metasedimentary rocks. Similar processes of mafic magma upper crustal intrusion and coeval silicic melt generation appear to have occurred in other regions across the Pacific Northwest during the mid-Miocene flood basalt event. Caldera-derived eruptive products are present in the SC; however, voluminous caldera-forming events did not typify SC activity. Rather, a paucity of caldera-forming silicic volcanism distinguishes the SC from coeval mid-Miocene Oregon Plateau volcanic fields (e.g., McDermitt, Lake Owyhee, northwest Nevada) as well as other silicic-dominated volcanic fields that are typically associated with the younger Snake River Plain--Yellowstone volcanic province.
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