The genesis of Triassic plutons along the continental margin arc of southern California will be studied by U-Pb zircon geochronology, trace element analysis, and by Nd, Sr, and Pb isotope analyses. These analyses will allow the relative roles of upper crustal assimilation and fractionation to be ascertained for the stages of pluton evolution. Triassic plutons have been little studied until now and the data will provide much needed information on the early evolution of the magmatic arc. The results of this study will have important implications for the tectonic evolution of southern California and for the composition of the Proterozoic lithosphere in the region.
