The northern Sierra terrane of California contains extensive exposures of a Jurassic volcano-plutonic assemblage that formed on the Pacific margin of north American. If offers the possibility of placing tight limits on the timing of tectonic events including arc magmatism, metamorphism and deformation associated with building of the arc and its subsequent development and final destruction. The work involves using fossil ages and extensive radiometric age determinations from various phases of the plutonic assemblage. When integrated with other data, the detailed chronology of structural and magmatic events established for the study area will allow rigorous comparison with other mid-Mesozoic terranes in the Sierra and will help evaluate regional tectonic models.
