Overview map of the Emigrant Gap mafic complex (EG), showing other Jurassic mafic complexes of the Sierra Nevada batholith.
Emigrant Gap gabbronorite outcrop with light and dark plagioclase- and pyroxene-rich segregations.
Dunite formed as a cumulate in the upper crust by subduction-zone magmatism.
Ductile deformation of plagioclase- and pyroxene-rich layers formed in a dynamic mafic crystal mush system.
Overview map of the Emigrant Gap mafic complex (EG), showing other Jurassic mafic complexes of the Sierra Nevada batholith.
Emigrant Gap gabbronorite outcrop with light and dark plagioclase- and pyroxene-rich segregations.
Dunite formed as a cumulate in the upper crust by subduction-zone magmatism.
Ductile deformation of plagioclase- and pyroxene-rich layers formed in a dynamic mafic crystal mush system.
Plutons record time-integrated intrusive processes. Using field geology and igneous petrology tools (whole-rock and mineral compositions, and thermodynamic modeling), we decipher the processes that primitive arc magmas experienced in the upper crust. The Emigrant Gap mafic complex, the most primitive intrusive complex of the Sierra Nevada, reveals relatively low-water mafic magmas that experienced open-system processes including infiltration and subsequent reaction of melts transiting through crystal rich magma “mush” and hybridization between the mush and a new batch of felsic melt in an upper-crustal volcanic reservoir.