An orogenic plateau in the southern U.S. Cordillera?

美国南部科迪勒拉山脉的造山高原？

• 批准号: 2344655
• 负责人: James Chapman
• 金额: $ 27.02万
• 依托单位: University of Texas at El Paso
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-15 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2344655&HistoricalAwards=false
• 关键词: orogenic; plateau; southern; U.S.; Cordillera

The mountain ranges of western North America, often collectively called the North American Cordillera, are excellent examples of ancient plate tectonic systems associated with collisions between oceanic and continental plates. However, it is unclear how the southern U.S. Cordillera fits within this collisional framework. Several features of the southern U.S. Cordillera suggest that the region may have been characterized by an elevated plateau, similar to today's elevated plateau in the Great Basin area of Nevada. At present, there is no accepted mechanism or theory for how the crust may have been thickened in the southwestern U.S. to create this plateau. This project will test whether an elevated plateau and associated thickened crust previously existed in the southern Arizona region and determine the mechanisms by which such a plateau could have been constructed. This project is led by a first-time NSF investigator at the University of Wyoming, includes a first-generation Hispanic Ph.D. student, and will incorporate undergraduate student research projects. Students will gain experience in laboratory and field methods, including geologic mapping. Project participants will also create a series of short-format videos for public release that document research activities of the project.The goal of this project is to test the hypothesis of whether an orogenic plateau, the "Arizonaplano" existed in the southern U.S. Cordillera during the late Mesozoic to early Cenozoic and constrain the mechanisms by which such a plateau could have been constructed. The initial phase of this work will use geochemical indices (e.g., La/Yb) from intermediate arc-related igneous rocks to determine paleo-crustal thickness. The second phase will include new geologic mapping and structural analyses in a series of mountain ranges in southern Arizona to determine whether low-angle, "Sevier-style" thrust faults exist, were regionally extensive, and could have thickened the crust. Recent discoveries and preliminary mapping provides an opportunity to correlate structural units across mountain ranges and assemble regional-scale cross sections for tectonic syntheses. The final phase of this research will link the tectonothermal history of Cretaceous to Paleogene sedimentary rocks to the deformation history of the region. This work has important relevance beyond the regional study area by helping to constrain the Mesozoic evolution of the Cordilleran orogen in the southwestern U.S.This project is jointly funded by the Tectonics program in the division of Earth Sciences and the Established Program to Stimulate Competitive Research (EPSCoR).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.

北美西部的山区范围通常统称为北美山内列拉（North America Cordillera），是与海洋和大陆板之间碰撞相关的古代板块构造系统的绝佳例子。但是，目前尚不清楚美国南部山脉如何适合这个碰撞框架。美国南部科迪勒拉（Cordillera）的几个特征表明，该地区的特征是高高的高原，类似于当今内华达州大盆地地区的高原高原。目前，对于在美国西南部如何变厚的地壳来创造这种高原的机制或理论尚无公认的机制或理论。该项目将测试在亚利桑那州南部地区是否存在先前存在的高原和相关的增厚地壳，并确定可以建造这种高原的机制。该项目由怀俄明大学的首次NSF调查员领导，其中包括第一代西班牙裔博士学位。学生，并将纳入本科生研究项目。学生将获得实验室和现场方法的经验，包括地质映射。项目参与者还将创建一系列简短的视频，用于公开发布该项目的研究活动。该项目的目的是测试在中学晚期的中学期间，在美国南部的康德利拉（Arizonaplano）是否存在造型高原，“亚利桑那普拉诺”（Arizonaplano）的假设，并在早期的碳酸盐中限制了该机制，并通过建造了该机制来构建该机制。这项工作的初始阶段将使用与中间弧相关的火成岩中的地球化学指数（例如LA/YB）来确定古壳厚度。第二阶段将包括在亚利桑那州南部一系列山脉中进行的新地质映射和结构分析，以确定是否存在低角度的“ Sevier”推力断层，在区域性广泛，可能会增强外壳。最近的发现和初步映射提供了一个机会，可以将跨山脉范围内的结构单元相关联，并组装构造合成的区域尺度横截面。这项研究的最后阶段将将白垩纪的构造历史与古代沉积岩与该地区的变形史联系起来。这项工作通过帮助约束美国西南部的Cordilleran造山基因的中生代进化以外的重要相关性，该项目由地球科学部的构造计划和既定计划共同资助，并启发竞争性研究（EPSCOR）的既定范围。影响审查标准。