The role of margin-parallel translations of accreted oceanic terranes is of current interest in transpressional orogens. This is an interdisciplinary investigation of deformed and metamorphosed oceanic rocks on islands off Baja California Sur, Mexico. The islands contain island arc assemblages, ophiolitic rocks, blueschist-facies subduction-related rocks and sparse cover, the ages of which are unknown but thought to be Mesozoic. This study will determine the ages of crystallization, coding, and metamorphism of the igneous rocks and will obtain geochemical, biostratigraphic, structural and paleomagnetic data. The results will be used to correlate tectonic terranes in western and southern Mexico and to determine the timing and magnitude of margin-parallel displacements. These findings will place important constraints on the tectonic evolution of the southern Cordillera of the western North American plate.
