Testing Models of Crustal Growth in the Neoproterozoic Arabian-Nubian Shield

位于非洲东北部和阿拉伯西部的阿拉伯-努比亚盾(ANS)包含了地球新元古代(1000-544 Ma)年轻地壳的很大一部分。这种地壳是由与现代板块构造难以区分的过程形成的，由蛇绿岩装饰的缝合线分隔的明确的构造地层地体证明了这一点。因此，ANS是检验我们对大陆地壳形成的理解所面临的核心争议的理想工具：汇聚边缘的岩浆贡献与地幔热柱的贡献的重要性，无论是作为沉积的海洋高原还是作为底侵物质。该项目将通过重点研究沙特阿拉伯西部Bir‘r Umq缝合带附近的地体的起源和演化，来测试用于ANS大陆增长的羽流模型的可行性。主要目标是将当地详细的构造、岩石地层和岩石学信息与主要火山和岩浆单元的构造背景和源区的综合地球化学、同位素和地质年代学约束结合起来。学术价值：拟议的研究有望从根本上促进对新元古代陆壳形成机制和时间的科学理解，对现代过程具有重大影响。更广泛的含义：这个项目是由博士生开发的，也是为博士生开发的，研究和教育的融合也是如此。了解新元古代地壳生长对了解这一时期全球大气、水球和生物圈的变化具有重要意义，因此将有助于了解地球系统和过程。这项研究的结果也将有助于边缘“大陆岩石圈破裂”实验，因为红海(边缘焦点)的开放在很大程度上受控于前寒武纪构造的重新激活，如Bir‘r Umq缝合带。该项目还促进了美国科学家和新成立的沙特地质调查局之间的国际合作。

EAR-0309799SternThe Arabian-Nubian Shield (ANS) in northeast Africa and western Arabia contains a large portion of Earth's Neoproterozoic (1000-544 Ma) juvenile crust. This crust formed by processes indistinguishable from those of modern plate tectonics, as witnessed by well-defined tectonostratigraphic terranes separated by ophiolite-decorated sutures. The ANS is therefore ideal for testing the central controversy facing our understanding of continental crust formation: the importance of magmatic contributions at convergent margins vs. those of mantle plumes, either as accreted oceanic plateaux or as underplated material. This project will test the viability of the plume model for continental growth in the ANS by focusing on the origin and evolution of the terranes adjacent to the Bi'r Umq suture in western Saudi Arabia. The primary objective is to combine locally detailed structural, lithostratigraphic, and petrological information with comprehensive geochemical, isotopic, and geochronological constraints on the tectonic setting and source regions of major volcanic and magmatic units. Intellectual Merit: The proposed research promises to contribute fundamentally to scientific understanding of the mechanisms and timing of continental crust formation in the Neoproterozoic, with significant implications for modern processes. Broader Implications: This project was developed by and for a doctoral student and so is a confluence of research and education. Understanding Neoproterozoic crustal growth has important implications for understanding global atmospheric, hydrospheric, and biospheric changes during this time, and so will contribute to understanding Earth systems and processes. The results of this study will also contribute to the MARGINS "Rupturing Continental Lithosphere" experiment, as the opening of the Red Sea (a MARGINS focus site) is largely controlled by reactivation of Precambrian structures such as the Bi'r Umq suture. The project also promotes international collaboration between scientists from the U.S. and the newly formed Saudi Geological Survey.