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

北美洲西部的山脉，通常统称为北美科迪勒拉山脉，是与海洋和大陆板块之间的碰撞有关的古代板块构造系统的绝佳例子。然而，目前还不清楚美国南部的科迪勒拉山脉如何适应这种碰撞框架。美国南部科迪勒拉山脉的几个特征表明，该地区可能是一个高地，类似于今天内华达州大盆地地区的高地。目前，还没有公认的机制或理论来解释美国西南部的地壳是如何增厚以形成这一高原的。该项目将测试亚利桑那州南部地区以前是否存在一个隆起的高原和相关的加厚地壳，并确定可能形成这样一个高原的机制。该项目由怀俄明州大学的第一次NSF调查员领导，包括第一代西班牙裔博士。学生，并将纳入本科生的研究项目。学生将获得实验室和现场方法的经验，包括地质测绘。项目参与者还将制作一系列记录项目研究活动的短格式视频供公众发布。该项目的目标是验证中生代晚期至新生代早期美国科迪勒拉南部是否存在造山高原“Arizonaplano”的假设，并限制这种高原可能形成的机制。这项工作的初始阶段将使用地球化学指标（例如，La/Yb），以确定古地壳厚度。第二阶段将包括对亚利桑那州南部一系列山脉进行新的地质测绘和结构分析，以确定是否存在低角度的“塞维尔式”逆冲断层，这些断层在区域范围内很广，可能使地壳增厚。最近的发现和初步测绘提供了一个机会，可以将各山脉的结构单元联系起来，并为构造合成收集区域尺度的横截面。这项研究的最后阶段将把白垩纪到古近纪沉积岩的构造历史与该地区的变形历史联系起来。这项工作具有重要的相关性超出了区域研究领域，有助于限制中生代的演变的科迪勒拉造山带在美国西南部这个项目是由共同资助的构造计划在地球科学和既定的计划，以刺激竞争力的研究（EPSCoR）部门该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查进行评估，被认为值得支持的搜索.

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.