RUI: Collaborative Research: Early Cenozoic basin development in the southwestern US: a record of extensional collapse following subduction of an oceanic plateau?

RUI：合作研究：美国西南部新生代早期盆地发育：海洋高原俯冲后伸展塌陷的记录？

• 批准号: 1946349
• 负责人: Francis Sousa
• 金额: $ 12.01万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-01 至 2024-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1946349&HistoricalAwards=false
• 关键词: RUI; Collaborative; Research; Early; Cenozoic

Subduction zones represent some of the most tectonically active regions on earth. Changes in the angle of the downgoing plate can control volcanism, faulting, and basin development in the overlying continental crust. The Maniobra and Goler Formations, exposed in the Mojave Desert in southern California, provide evidence for the development of extensional basins on the overriding continental plate related to low-angle subduction in Late Cretaceous to Eocene time (~80-50 million years ago). This research will test the hypothesis that Late Cretaceous extension resulted in the development of the Maniobra and Goler Basins, while simultaneously introducing more than 50 undergraduate and 2 Masters students to the techniques of basin analysis. The field sites in the Mojave Desert, located within 3 hours of Los Angeles, provide a natural laboratory to train the next generation of geoscientists. Students from a Hispanic-serving institution will learn modern geologic techniques, such as geologic mapping, geochronology, paleomagnetism, and thermochronology, that can be applied to their graduate and post-graduate careers. Analytical data from this research will be made available on community databases, and results of the proposed research will be used to construct a publicly-available online learning module.Recent tectonic models of the southwestern US Cordillera have invoked the subduction of an oceanic plateau, the conjugate Shatsky Rise, as a driver of slab flattening, subduction erosion and arc cessation in Late Cretaceous to Eocene time. Subduction, and subsequent passage of the plateau, likely promoted extension and associated regional paleogeographic changes, such as basin development and block rotations. This study targets the Goler and Maniobra Formations, which are the only Late Cretaceous to Eocene basinal strata located along the interpreted subduction pathway. This research will test the hypothesis that gravitational collapse in the wake of plateau subduction was widespread across the Mojave region in the Late Cretaceous to early Cenozoic and led to the development of supra-detachment basins and the exhumation of relict subduction complexes. This research will incorporate new mapping of stratigraphic and structural relationships, combined with magnetostratigraphy, detrital zircon provenance analysis, and basement and detrital thermochronology. This data will constrain the timing and duration of basin formation and enable the evaluation of different tectonic models of basin development. New basin analysis results from the Late Cretaceous to Eocene Goler and Maniobra Formations will provide a crucial link between plateau subduction processes and related surface deformation and will highlight the complexity of tectonic evolution along a highly segmented margin over time.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.

俯冲带代表了地球上一些构造最活跃的地区。下行板块角度的变化可以控制上覆大陆地壳的火山作用、断裂作用和盆地发育。加利福尼亚南部莫哈韦沙漠的Maniobra组和Goler组为晚白垩世至始新世（~ 8000万~ 5000万年前）上覆大陆板块低角度俯冲相关伸展盆地的发育提供了证据。本研究将验证晚白垩世伸展导致Maniobra和Goler盆地发育的假设，同时将50多名本科生和2名硕士研究生引入盆地分析技术。莫哈韦沙漠的研究基地距离洛杉矶3小时车程，为培养下一代地球科学家提供了一个天然实验室。来自西班牙裔服务机构的学生将学习现代地质技术，如地质制图、地质年代学、古地磁学和热年代学，这些技术可以应用于他们的研究生和研究生的职业生涯。这项研究的分析数据将在社区数据库中提供，拟议的研究结果将用于构建一个公开的在线学习模块。美国西南部科迪勒拉最近的构造模型援引了海洋高原的俯冲作用，即共轭沙茨基隆起，作为晚白垩世至始新世时期板块变平、俯冲侵蚀和弧停止的驱动因素。俯冲和随后的高原通道可能促进了伸展和相关的区域古地理变化，如盆地发育和地块旋转。Goler组和Maniobra组是唯一位于解释的俯冲路径上的晚白垩世至始新世盆地地层。本研究将验证在晚白垩世至新生代早期，莫哈韦地区普遍存在高原俯冲后的重力塌陷，并导致了超滑脱盆地的发育和残余俯冲杂岩的发掘。该研究将结合磁地层学、碎屑锆石物源分析以及基底和碎屑热年代学，对地层和构造关系进行新的制图。这些数据将限制盆地形成的时间和持续时间，并使盆地发育的不同构造模式的评价成为可能。从晚白垩世到始新世的Goler组和Maniobra组的新盆地分析结果将提供高原俯冲过程和相关地表变形之间的关键联系，并将突出沿高度分段边缘的构造演化的复杂性。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。