Chronology of Mesozoic Flood Basalt Volcanism in Brazil

该项目旨在提供大大改进的年代学，使用40Ar/39Ar方法测定南美洲四个中生代洪水玄武岩省的年龄和持续时间。将获得的数据的预期应用包括：1)精确和准确地测定每一次火山活动的开始和持续时间，以约束洪水玄武岩成因的模式，以及与大陆裂谷和热点的关系；2)检验与大规模灭绝的可能相关性，特别是巴拉那的情况，它可能与侏罗纪-白垩纪的灭绝事件有关；3)对南美大陆中生代视极漂移路径进行了精确和准确的时间刻度，以便于构造研究和南美运动与特里斯坦-达库尼亚热点位置的对比；4)在一个亟待改进的时间区域进行了地磁极性时间尺度(GPTS)的刻度。这个为期两年的项目将与圣保罗大学的巴西合作者联合进行实地考察和出版；其他合作者是Mark Richards博士(大学。加州，伯克利)和Robert Coe博士(大学加利福尼亚州、圣克鲁斯)。

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).