The Early Proterozoic orogenic belt in Arizona is a wide complex zone of deformed continental crust that was accreted to North America between 1800 and 1600 Ma. Prior work has identified several major crustal blocks, bounded by shear zones, that underwent different structural histories prior to their juxtaposition sometime after 1695 Ma. These new data strongly suggests that the Proterozoic of central Arizona evolved by a process of accretionary tectonics analogous to accretionary collages in Phanerozoic orogens. This renewal project, in collaboration with workers at Washington University, will extend mapping coverage and structural analysis to a larger area, including several terranes and possible suture zones. Precise U-Pb geochronology will be applied to constrain the sequence and timing of deformation and metamorphic events. Results will address the problem of evolution of the Proterozoic plate margin along the southern edge of the North American continent, and mechanisms of continental growth.
