Early to Middle Proterozoic Construction of the Mojave Province, Southwestern United States

Zircon and monazite U-Pb geochronology of rocks in the western Mojave province of the southwest US reveals that the Proterozoic arc exposed there shares an intrusive and deformational history with rocks exposed further east in the Yavapai and Mazatzal belts after approximately 1780 Ma. Consequently, it seems likely that the Mojave province was contiguous with these other Laurentian provinces by that time. Isotopic and geochronologic data also suggest that Mojave province plutonic rocks inherit their distinctive isotopic compositions, at least in part, from an enriched lithospheric mantle source and interaction with sedimentary rocks containing Archean detritus.