U.S.-Mexico Collaborative Research: Plio-Quaternary uplift and tectonism of western Mexico from geologic studies and 36Cl cosmogenic isotopes

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0123000RighterThis US-Mexico award will fund a collaborative project between Dr. Kevin Righter, of the Lunar and Planetary Institute, in collaboration with Dr. Jose Rosas-Elguera of the University of Guadalajara, Mexico. The researchers aim to study the Cenozoic volcanic and tectonic evolution of western Mexico. The project will help to determine ages of more recent volcanic activity in western Mexico, and improve our understanding of the spatial and temporal distribution of volcanism. The Division of Earth Sciences will also contribute partial support for this project. The Cenozoic volcanic and tectonic evolution of western Mexico has been influenced by two processes - extension from opening of the Gulf of California, and compression from the subduction of the Rivera Plate beneath the North American Plate. Although there is some evidence for uplift in western Mexico, the timing of that uplift is uncertain. It may be young and related entirely to the current subduction environment. Or it could date back to the mid-Cenozoic, when the region started undergoing change as a result of the transfer of Baja California to the Pacific Plate. In order to understand the uplift history of this region, the researchers propose to determine regional uplift rates in the Atenguillo region of western Mexico, using new isotopic methods. The technique has been tested successfully on a small suite of samples. In addition, a selected suite of very young volcanic rocks will be dated from the western Mexico region. Results of this study will be integrated with geologic studies of the area, and also with the results of recent and ongoing regional plate motion and GPS studies.