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

位于非洲东北部和阿拉伯半岛西部的阿拉伯-努比亚地盾（ANS）包含了大部分新元古代（1000-544 Ma）的幼年地壳。 这种地壳的形成过程与现代板块构造的过程没有什么区别，这一点可以从被蛇绿岩装饰的缝合线分隔开的构造地层学中得到证明。因此，ANS是测试我们对大陆地壳形成的理解所面临的核心争议的理想选择：会聚边缘岩浆贡献的重要性与地幔柱的重要性，无论是作为增生的海洋高原还是作为底侵物质。该项目将通过侧重于沙特阿拉伯西部Bi 'r Umq缝合线附近的地幔柱的起源和演变，检验ANS大陆增长的地幔柱模型的可行性。主要目标是将联合收割机局部详细的构造、岩石地层和岩石学信息与对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相结合。智力优势：拟议的研究有望从根本上促进科学认识的机制和时间的大陆地壳形成在新元古代，具有重大意义的现代进程。更广泛的影响：该项目是由一名博士生开发的，因此是研究和教育的融合。了解新元古代地壳生长对了解这一时期全球大气、水圈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MARGINS的“破裂大陆岩石圈”实验，因为红海（MARGINS焦点地点）的开放在很大程度上受到前寒武纪结构（如Bi 'r Umq缝合线）的重新激活的控制。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.