Chronology of Mesozoic Flood Basalt Volcanism in Brazil

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This project is intended to provide vastly improved chronology, using 40Ar/39Ar methods for the age and duration of four Mesozoic flood basalt provinces of South America. The anticipated applications of the data to be acquired include: 1) Precise and accurate dating of the inception and duration of volcanism in each case to constrain models of flood basalt genesis, and the relations to continental rifting and hotspots; 2) To test for possible correlations with mass extinctions, particularly in the case of the Parana which may be related to the Jurassic-Cretaceous extinction event; 3) Precise and accurate temporal calibration of a Mesozoic Apparent Polar Wander Path for the South American continent to facilitate tectonic studies and comparison of South America's motion with position of the Tristan da Cunha hotspot; 4) Calibration of the Geomagnetic Polarity Time Scale (GPTS) in a time region badly needing improvement. This two-year project will involve joint fieldwork and publication with Brazilian collaborators at the University of Sao Paulo; additional collaborators are Dr. Mark Richards (Univ. California, Berkeley) and Dr. Robert Coe (Univ. California, Santa Cruz).