Laramide Relamination of Mantle Lithosphere Beneath the Colorado Plateau: A Xenolith Study

该奖项将为地球科学领域的初级研究人员的职业发展提供支持。这项研究将促进新的合作，并加强与亚利桑那大学和莱斯大学科学家的旧伙伴关系。该项目将为三名本科生的培训提供知识基础和支持。一个基于课堂和实地的推广计划，通过亚利桑那大学推广，并打算在6-8年级的学生，将与本研究相结合。通过该计划制作的课程材料将通过科学教育资源中心（SERC）与地球科学界分享。这项研究的结果将有助于实现“地球镜”的基本目标，并将发表在同行审查的主要科学期刊上和一篇非专业人士的文章中。从这项研究中获得的数据将在综合地球数据应用程序，地球化学和PetDB数据库中向公众开放。越来越多的地球物理数据表明，北美西部大陆地幔的地质最近的流动性。几条证据表明，南加州之下的地幔岩石圈被构造位移向东晚白垩世的一幕浅俯冲和“再分层”的科罗拉多高原过渡带（亚利桑那州中部）之下的大陆岩石圈的基础。首席研究员将通过比较这两个地区的地幔捕虏体的成岩和热历史来检验这一假设。如果亚利桑那州和加州捕虏体套以类似的方式演化，那么就可以为美国西南部地幔岩石圈的主要中生代位移和随后的重建提供强有力的证据。这项研究将提供一个地球动力学和地质背景，以了解北美西部地幔位移。这项研究将为美国西南部地幔岩石圈的起源和演化提供关键制约因素，提高了识别全球现代和古代类似环境的能力，提高了对克拉通活动边缘过渡区地幔岩石圈稳定性的俯冲角影响的理解，以及很有可能识别出在亚利桑那州中部下方“重新分层”的南加州地幔岩石圈残余。这一结果意味着南加州地幔碎片的500公里构造位移，并提供了有趣的解释长期强度的科罗拉多高原相对于邻近的地质省和活跃的岩石圈拆沉下高原。

This award will provide support for the career development of a junior investigator in the area of Earth Sciences. The study will foster new collaborations and enhance old partnerships with scientists at the University of Arizona and Rice University. This project will constitute the intellectual basis and support the training for three undergraduate students. A classroom- and field-based outreach program, through University of Arizona Extension and intended for students in grades 6-8, will be integrated with this research. Course materials produced through this program will be shared with the geosciences community through the Science Education Resource Center (SERC). The results from this study will contribute to the fundamental goals of Earthscope and will be published in major peer-reviewed scientific journals and in an article for non-specialists. Data resulting from this study will be made accessible to the public in Integrated Earth Data Applications, EarthChem, and PetDB databases.A growing body of geophysical data suggests geologically recent mobility of the continental mantle beneath western North America. Several lines of evidence suggest that mantle lithosphere beneath southern California was tectonically displaced eastward by a Late Cretaceous episode of shallow subduction and "relaminated" to the base of the continental lithosphere beneath the Colorado Plateau transition zone (central Arizona). The principal investigator will test this hypothesis by comparing the petrogenetic and thermal histories of mantle xenoliths derived from both areas. If Arizona and California xenolith suites evolved in a similar manner, then a strong case can be made for major Phanerozoic displacement and subsequent reconstruction of southwest U.S. mantle lithosphere. This study will provide a geodynamic and geologic context to understand mantle displacements beneath western North America. This research will provide key constraints on the origin and evolution of mantle lithosphere beneath the southwest U.S., an enhanced ability to recognize modern and ancient analogous settings worldwide, an improved understanding of the effects of subduction angle on the stability of mantle lithosphere at craton active margin transition zones, and a high probability of recognizing a remnant of the southern California mantle lithosphere that has been "relaminated" beneath central Arizona. This result would imply a 500 km tectonic displacement of the southern California mantle fragment and provide intriguing explanations for the long-term strength of the Colorado Plateau relative to adjacent geologic provinces and for active lithospheric delamination beneath the plateau.