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.

关于广大大陆内部区域的深层地表历史存在一些基本问题。在北美北极地区，不同年龄的含钻石金伯利岩岩浆携带着从地球深处夹带的岩石碎片，通过年龄、结构和历史不同的大陆块喷发。不同的关系提供了评估该地区深层和浅层演变的机会，以阐明不同深度的历史是如何联系在一起的。该项目将发展新的并加强美国和加拿大科学家之间现有的跨学科研究关系，研究地球不同深度的过程，培训一名科罗拉多大学博尔德分校博士生，并通过支持代表性不足的少数族裔暑期实习生来促进多样性。研讨会将聚集项目团队以及地质学、岩石学和地球动力学界的其他成员，以改善这些团体之间的联系，并加深对地球深处和地表过程如何相互联系的理解。该项目的目标是破译整个北美北极的显生宙地表历史，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作用历史的联系，并考虑岩石圈下过程在这些记录中的作用。这将通过利用北极金伯利岩管内保存的独特地幔到地表记录来实现。具体来说，该项目将（1）通过将金伯利岩和基底样本的 AHe 数据与管道所承担的表面演化的地质约束相结合，破译北极表面历史及其空间变化，（2）将该表面记录与成分和演化进行比较阿尔伯塔大学项目的合作者正在通过对这些相同的金伯利岩及其地幔捕虏体套件的深入研究来绘制底层地幔根的图，(3) 使用热化学的 3D 动态模型对流来预测北美下方软流圈上部的显生宙热演化。该项目由地球科学部的岩石学与地球化学、地球物理学和构造学项目联合支持。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。