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

关于广阔大陆内部区域的深时地表历史存在着一些基本问题。在北美北极，不同年代的含金刚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、结构和历史截然不同的大陆块爆发。不同的关系提供了一个机会，以评估整个地区的深层和浅层的演变，以阐明如何在不同的深度的历史是联系在一起的。该项目将开发新的和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，培养一名CU-Boulder博士生，并通过支持代表性不足的少数民族暑期实习生来促进多样性。一个研讨会将聚集项目团队和地质，岩石学和地球动力学社区的其他成员，以改善这些团体之间的联系，并加强对地球深部通过表面过程是如何连接的理解。该项目的目标是破译整个北美北极地区的中生代地表历史，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，并考虑这些记录中岩石圈下过程的作用。这将通过利用保存在北极金伯利岩管道内的独特地幔到地表记录来实现。具体而言，该项目将（1）通过将金伯利岩和基底样品的AHe数据与管道所承载的地表演化的地质约束相结合，破译北极地表历史及其空间变化，（2）将该地表记录与底层地幔根的组成和演化进行比较，该项目的阿尔伯塔大学合作者通过对这些金伯利岩及其地幔捕虏体的深入研究，（3）利用三维热化学对流动力学模型预测北美地区下地幔上部的中生代热演化。该项目由地球科学部的岩石学地球化学、地球物理学和构造学项目共同支持。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标准进行评估，被认为值得支持。

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.