CAREER: Testing Models of Cretaceous Cordilleran Paleogeography: An Integrated Provenance Study of Four Basins

该奖项是根据2009年美国复苏和再投资法(公法111-5)资助的。构造变形、岩浆作用以及与之相关的侵蚀速率和古排水系统的变化直接影响活动构造背景下的沉积盆地演化。因此，对汇聚边缘沉积盆地的详细和可靠的评价可能提供最完整的古汇聚边缘系统中的构造和岩浆事件的记录。北美科迪勒拉为开发这一可靠的物源技术提供了理想的环境，因为整个造山带广泛的地质年代学、地球化学和同位素研究为比较沉积物来源和要收集的物源数据奠定了明确的基础。由于对西部科迪勒拉的中生代和年轻的古地理演化没有达成明确的共识，因此物源研究结果将解决长期存在的地体平移和旋转问题。拟议研究的科学价值在于开发了一种综合的沉积物源技术，该技术将普遍适用于世界各地汇聚系统中的盆地演化研究。建议的盆地物源分析将沉积岩石学与碎屑锆石分析、全岩主要元素和微量元素地球化学以及钕同位素分析相结合，以开发一种详细的方法来研究应该可以转移到世界各地的类似系统的会聚边缘盆地。由多种物源工具组合而成的可靠的地球化学和地质年代学数据集包括来自一个盆地内所有粒度和成分的信息-S地层学。包括盆地地层更均一的细粒成分的综合物源分析将使盆地内和盆地之间有更好的对比。其沉积物源可能提供与物源区的关键联系的白垩纪盆地包括不列颠哥伦比亚省南部和华盛顿州北部的梅托盆地，俄勒冈州东部的奥楚科盆地，俄勒冈州南部和加利福尼亚州北部的霍恩布鲁克组，以及加利福尼亚州的大谷群。除了大谷群以外，这些白垩纪科迪勒盆地的物源已在很大程度上进行了调查研究，而且这些盆地都没有通过整合所有提出的物源工具进行研究。总而言之，这些不同的来源方法可以记录单一盆地内沉积物来源随时间和空间的演变，改进地层年龄控制，并在单一盆地内和盆地之间更好地进行对比。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Tectonic deformation, magmatism, and associated changes in erosion rates and paleodrainage systems directly affect sedimentary basin evolution in active tectonic settings. Thus, a detailed and robust evaluation of convergent margin sedimentary basins may provide the most complete record of tectonic and magmatic events in ancient convergent margin systems. The North American Cordillera provides an ideal setting for developing this robust provenance technique because extensive geochronologic, geochemical, and isotopic studies throughout the orogen establish an explicit basis for comparing sediment sources against the provenance data to be collected. Because no clear consensus has been reached on the Mesozoic and younger paleogeographic evolution of the western Cordillera, provenance results will address longstanding questions of terrane translation and rotation. The scientific merit of the proposed study lies in the development of an integrated sedimentary provenance technique that will be generally applicable to basin evolution studies in convergent systems worldwide. The proposed basin provenance analysis integrates sedimentary petrography with detrital zircon analysis, whole-rock major and trace-element geochemistry, and neodymium isotopic analysis to develop a detailed approach to studying convergent margin basins that should be transferable to similar systems around the world. The robust geochemical and geochronologic dataset resulting from a combination of multiple provenance tools includes information from all grain sizes and compositions within a basin?s stratigraphy. Integrated provenance analysis that includes the more homogenized fine-grained component of basin strata will permit better correlation within and between basins. Cretaceous basins whose sedimentary provenance may provide crucial links to source regions include the Methow basin in southern British Columbia and northern Washington State, the Ochoco basin in eastern Oregon, the Hornbrook Formation in southern Oregon and northern California, and the Great Valley Group in California. With the exception of the Great Valley Group, the provenance of these Cretaceous Cordilleran basins has been studied largely at a reconnaissance level, and none of these basins have been studied through integration of all proposed provenance tools. Together, these various provenance methods permit documentation of the evolution of sediment sources through time and space within a single basin, improved stratigraphic age control, and better correlation within a single basin and between basins.