Collaborative Research: Testing models for the Late Jurassic Nevadan Orogeny: Age, provenance, and structural evolution of the Galice and Mariposa basins, OR and CA

拟议的研究将提高对北美大陆边缘的发展的理解，在南部俄勒冈州和北方加州之前和期间的收缩变形的关键和知之甚少。在这段时间（最后侏罗纪），造山运动分别关闭了西部克拉马斯和塞拉山脉的Galice和马里波萨沉积盆地。盆地的沉积物来源、沉积年龄以及变质和变形程度的细节可能会在造山活动之前和期间提供最好的地质记录。该项目为本科生和研究生提供了关键的教育优势，需要整合一系列在课堂上无法复制的学科知识和技能。该项目将在研究生和本科阶段招募妇女和代表性不足的少数民族学生，这些学生将是研究的全面参与者，而不是观察员。通过这项研究的体验式学习将提供直接转化为STEM劳动力的技能开发和培训。此外，强调这项研究和关键领域的实地指南将通过林务局地区和NSF Flyover Country®应用程序广泛传播，提高公众的科学素养。对金矿开采的持续兴趣和形成本研究重点的岩石的开采历史增加了公众参与的可能性。克拉马斯山脉和西锡尔兰省的上侏罗纪Galice和马里波萨组长期以来一直被认为是了解美国科迪勒拉大陆边缘中生代中期历史的基础。晚侏罗世Nevadan造山带的两种相反的构造模式对Galice和马里波萨沉积的构造背景和时代有不同的解释。第一个模型调用的成因的马里波萨组在洋内盆地，逐渐关闭沿着相对倾斜的俯冲带，而年龄相当Galice组代表一个弧间盆地原产于北美西部边缘。在第二个模型中，两个地层都发生在沿北美西部边缘沿着向东倾斜的长期俯冲带上方的张扭盆地内。由于这些地层构成了晚侏罗世内华达变形过程中最年轻的岩石变形，沉积年龄，沉积物来源，以及变形的运动学和风格的细节是至关重要的通知拟议的构造模型和评估其可行性。对这些盆地进行了综合分析，包括岩相特征、碎屑锆石U-Pb年龄和Hf分析、重矿物分析、沉积构造解释、变质程度评估以及变形时间和运动学分析，将为修改和完善对晚侏罗世大陆边缘的理解提供一个强有力的框架。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估的支持。

The proposed research will improve the understanding of the development of the North American continental margin in southern Oregon and northern California just prior to and during a critical and poorly understood period of contractional deformation. During this time (the Latest Jurrassic), mountain building closed the Galice and Mariposa sedimentary basins in the western Klamath and Sierra mountains, respectively. Details of the basins’ sediment sources, depositional ages, and extent of metamorphism and deformation may provide the best geologic record just prior to and during the mountain-building event. The project provides key educational benefits for students at the undergraduate and graduate level, requiring integration of a range of disciplinary knowledge and skills that cannot be duplicated in a classroom. The project will recruit women and underrepresented minority students at graduate and undergraduate levels, and these students will be full participants in the research, not observers. The experiential learning through this research will provide skill development and training that will translate directly to the STEM workforce. In addition, field guides highlighting this research and key areas of interest will be broadly disseminated through Forest Service districts and the NSF Flyover Country® app, improving public scientific literacy. The ongoing interest in gold mining and the mining history of the rocks that form the focus of this research increase the likelihood of public engagement.The Upper Jurassic Galice and Mariposa Formations in the Klamath Mountains and western Sierran provinces have long been considered fundamental to understanding the mid-Mesozoic history of the U.S. Cordilleran continental margin. Two opposing tectonic models for the Late Jurassic Nevadan orogeny variously interpret the tectonic setting and age of Galice and Mariposa deposition. The first model invokes the genesis of the Mariposa Formation in an intra-oceanic basin that progressively closed along oppositely dipping subduction zones, while the age-equivalent Galice Formation represents an inter-arc basin native to the western margin of North America. In the second model, both formations occur within transtensional basins above an east-dipping, long-lived subduction zone along the western North American margin. Because these strata constitute the youngest rocks deformed during the Late Jurassic Nevadan deformation, details of depositional age, sediment provenance, and the kinematics and style of deformation are critical to informing the proposed tectonic models and assessing their viability. This comprehensive and integrated analysis of each of these basins that includes petrofacies characterization, detrital zircon U-Pb age and Hf analysis, heavy mineral analysis, interpretation of sedimentary structures, assessment of the degree of metamorphism, and analysis of the timing and kinematics of deformation, will provide a robust framework for modification and refinement of the understanding of the Late Jurassic continental margin.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.