Deciphering Lithospheric and Deeper Mantle Contributions to the Surface History of the North American Arctic From the Unique Mantle to Surface Record of Kimberlites

从独特的地幔到金伯利岩的地表记录，解读岩石圈和更深地幔对北美北极地表历史的贡献

• 批准号: 1844182
• 负责人: Rebecca Flowers
• 金额: $ 38.88万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1844182&HistoricalAwards=false
• 关键词: Deciphering; Lithospheric; Deeper; Mantle; Contributions

Fundamental questions exist about the deep-time surface history of vast continental interior regions. In Arctic North America, diamondiferous kimberlite magmas of diverse age that bear fragments of rock entrained from deep in the Earth erupted through continental blocks of contrasting age, structure, and history. The disparate relationships provide the opportunity to evaluate the deep and shallow evolution across the region to illuminate how the histories at different depths are linked. This project will develop new and reinforce existing cross-disciplinary research relationships among U.S. and Canadian scientists studying processes at different depths in the Earth, train a CU-Boulder PhD student, and foster diversity through support of an underrepresented minority summer intern. A workshop will gather the project team and other members of the geologic, petrologic, and geodynamic communities to improve ties among these groups and enhance understanding of how deep Earth through surface processes are connected. This project's goals are to decipher the Phanerozoic surface history across the North American Arctic, identify relationships with the architecture and history of the lithospheric mantle, evaluate connections with the history of kimberlite magmatism, and consider the role of sublithospheric processes in these records. This will be accomplished by exploiting the unique mantle to surface record preserved within Arctic kimberlite pipes. Specifically, this project will (1) decipher the Arctic surface history and its spatial variability by integrating AHe data for kimberlite and basement samples with geologic constraints on the surface evolution borne by the pipes, (2) compare this surface record with the composition and evolution of the underlying mantle roots, which are being mapped by the project's University of Alberta collaborators through intensive study of these same kimberlites and their mantle xenolith suites, and (3) use a 3D-dynamic model of thermochemical convection to predict the Phanerozoic thermal evolution of the upper asthenosphere below North America. This project is jointly supported by the Petrology & Geochemistry, Geophysics, and Tectonics programs in the Division of Earth Sciences.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.

关于广大大陆内陆地区的深时地表历史存在着一些基本问题。在北美洲的北极地区，不同年代的金伯利岩岩浆携带着来自地球深处的岩石碎片，从不同年代、结构和历史的大陆块体中喷发出来。不同的关系提供了评估该地区深层和浅层演化的机会，以阐明不同深度的历史是如何联系在一起的。该项目将在研究地球不同深度过程的美国和加拿大科学家之间发展新的和加强现有的跨学科研究关系，培养一名科罗拉多大学博尔德分校的博士生，并通过支持一名未被充分代表的少数民族暑期实习生来促进多样性。一个研讨会将召集项目团队和其他地质学、岩石学和地球动力学团体的成员，以改善这些团体之间的联系，并加强对通过地表过程连接地球深处的理解。该项目的目标是破译北美北极显生宙的地表历史，确定与岩石圈地幔的结构和历史的关系，评估与金伯利岩岩浆活动历史的联系，并考虑岩石圈下过程在这些记录中的作用。这将通过利用保存在北极金伯利岩管道中的独特地幔到地表的记录来完成。具体来说，该项目将(1)通过整合金伯利岩和基底样品的he数据，以及管道带来的地表演化的地质限制，破译北极地表历史及其空间变异性；(2)将地表记录与下垫地幔根的组成和演化进行比较，这是由该项目的合作者阿尔伯塔大学通过对这些金伯利岩及其地幔包体套的深入研究绘制的。(3)利用热化学对流三维动力学模型预测北美下方上层软流圈显生宙热演化。该项目由地球科学部岩石与地球化学、地球物理和构造学项目共同支持。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。