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

该奖项由2009年美国复苏和再投资法案（公法111-5）资助。构造变形、岩浆作用以及侵蚀速率和古排水系统的相关变化直接影响活跃构造环境中的沉积盆地演化。因此，对会聚边缘沉积盆地进行详细而可靠的评价，可以提供古代会聚边缘体系中构造和岩浆事件的最完整记录。 北美科迪勒拉山脉提供了一个理想的环境，发展这种强大的物源技术，因为广泛的地质年代学，地球化学和同位素研究整个造山带建立了明确的基础，比较沉积物来源对物源数据收集。由于没有明确的共识已达成中生代和年轻的古地理演化的西部科迪勒拉，物源的结果将解决长期存在的问题，西半球的平移和旋转。拟议研究的科学价值在于开发一种综合沉积物源技术，这种技术将普遍适用于全世界汇聚系统的盆地演化研究。拟议的盆地物源分析将沉积岩石学与碎屑锆石分析、全岩主要和微量元素地球化学以及钕同位素分析相结合，以制定一种详细的方法来研究收敛边缘盆地，这种方法应该可以转移到世界各地的类似系统。强大的地球化学和地质年代学数据集产生的组合，多个物源工具，包括信息，从所有的粒度和成分在一个盆地？的地层学。综合物源分析，包括更均匀的细粒成分的盆地地层，将允许更好的盆地内和盆地之间的相关性。 白垩纪盆地的沉积物源可能提供了与源区的关键联系，包括不列颠哥伦比亚省南部和华盛顿州北方的梅托盆地、俄勒冈州东部的奥乔科盆地、俄勒冈州南部和加州北方的霍恩布鲁克组，以及加州的大峡谷群。除了大峡谷群之外，这些白垩纪科迪勒拉盆地的物源主要是在勘测水平上研究的，没有一个盆地是通过整合所有提出的物源工具来研究的。 总之，这些不同的物源方法允许通过时间和空间在一个单一的盆地，改善地层年龄控制，并在一个单一的盆地和盆地之间的更好的相关性的沉积物源的演变文件。

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.