Timescales of Development of Sub-Ophiolite Subduction: High Precision U-Pb Dating and Geochemical Characterization of Late Magmatism and Metamorphism in the Oman-U.A.E. Ophiolite

亚蛇绿岩俯冲发育的时间尺度：阿曼-阿联酋地区晚期岩浆作用和变质作用的高精度 U-Pb 测年和地球化学特征

• 批准号: 1250522
• 负责人: Matthew Rioux
• 金额: $ 19.5万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-02-01 至 2016-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1250522&HistoricalAwards=false
• 关键词: Timescales; Development; Sub; Ophiolite; Subduction

The tectonic setting during ophiolite formation and emplacement are debated. The Samail ophiolite in Oman and the United Arab Emirates is the largest and one of the best-studied ophiolites in the world, and is an ideal place to study these processes. This research project uses high precision U-Pb zircon geochronology and radiogenic isotope, major and trace element geochemistry to study the evolution from formation of the ophiolite crust to development of thrusting below the ophiolite. The work will focus on late magmatic series that intruded the ophiolite mantle and crust, and metamorphic rocks and associated leucocratic pods within the metamorphic sole. The late magmatic series in the crust and mantle have isotopic and trace element signatures that have been attributed to thrusting or subduction below the ophiolite, and the combined dating and geochemical analyses will determine the timing of thrusting or subduction relative to crustal growth. Similar analyses from the metamorphic sole will provide a complimentary record within the under-thrust plate. The complete dataset will provide a detailed temporal record of the tectonic development of the ophiolite and help to differentiate between existing models of ophiolite formation. Ophiolites are thin slices of crust that formed at oceanic spreading centers and subsequently thrust onto the continents. Because ophiolites are easier to access than in-situ oceanic crust, and often expose cross sections through the crust and upper mantle, research on ophiolites has played a major role in the development of current models for the structure of the oceanic crust and the processes that form it. However, there are chemical differences between ophiolites and in-situ oceanic crust, which suggest ophiolites may form in more complex tectonic environments. To understand how observations from ophiolites can be applied to the formation of the oceanic crust, it is necessary to understand the tectonic setting during formation and emplacement of ophiolites. Several authors have proposed that ophiolites may form during the initial development of new subduction zones, and as a result, research on ophiolites may also provide insight into the processes of subduction initiation. The proposed research will generate a temporal and chemical record of the formation of the Semail ophiolite, providing insight into both the origin of ophiolites and potentially the processes of subduction initiation.

在蛇绿岩形成和安置期间的构造设置进行了辩论。阿曼和阿拉伯联合酋长国的Samail Ophiolite是世界上最大的，也是研究最佳的Ophiolites之一，是研究这些过程的理想场所。该研究项目使用高精度的U-PB锆石地质学和放射原性的同位素，主要和痕量元素地球化学，以研究从蛇绿岩壳形成到覆层下推力的发展的演变。这项工作将集中于侵入蛇绿岩和地壳的后期岩浆系列，并在变质鞋底内变质岩石和相关的耶和华豆荚。地壳和地幔中的岩浆系列具有同位素和痕量元件签名，这些特征归因于蛇胶岩下方的推力或俯冲，并且合并的约会和地球化学分析将确定相对于地壳生长的推力或降落的时间。从变质鞋底进行的类似分析将在不知情的板块内提供免费记录。完整的数据集将提供蛇绿岩的构造开发的详细时间记录，并有助于区分现有的蛇绿岩形成模型。蛇绿岩是在海洋扩散中心形成的薄片，随后将其推向大陆。由于蛇晶层比原位海洋壳更容易进入，并且经常通过地壳和上层地幔暴露横截面，因此对蛇绿岩的研究在当前模型的开发中起着重要作用，用于开发海洋壳结构及其形成它的过程。但是，蛇绿岩和原位海洋壳之间存在化学差异，这表明蛇绿岩可能在更复杂的构造环境中形成。为了了解如何将来自蛇绿岩的观测应用于海洋地壳的形成，有必要了解蛇绿岩的形成和增强过程中的构造环境。几位作者提出，在新的俯冲带的初始发展过程中可能会形成蛇纤维，因此，对蛇绿岩的研究还可以提供对俯冲启动过程的见解。拟议的研究将产生半链蛇落石形成的时间和化学记录，从而深入了解蛇纤维的起源以及潜在的俯冲启动过程。

项目成果

The Origin of Felsic Intrusions Within the Mantle Section of the Samail Ophiolite: Geochemical Evidence for Three Distinct Mixing and Fractionation Trends

• DOI: 10.1029/2020jb020760
• 发表时间: 2021-03
• 期刊: Journal of Geophysical Research: Solid Earth
• 作者: M. Rioux;M. Benoit;I. Amri;G. Ceuleneer;J. Garber;M. Searle;Kayla Leal

Petrochronology of Wadi Tayin Metamorphic Sole Metasediment, With Implications for the Thermal and Tectonic Evolution of the Samail Ophiolite (Oman/UAE)

• DOI: 10.1029/2020tc006135
• 发表时间: 2020-12-01
• 期刊: TECTONICS
• 影响因子: 4.2
• 作者: Garber, Joshua M.;Rioux, Matthew;Searle, Michael P.
• 通讯作者: Searle, Michael P.

High‐Precision U‐Pb Zircon Dating of Late Magmatism in the Samail Ophiolite: A Record of Subduction Initiation

萨迈伊蛇绿岩晚期岩浆活动的高精密 U-Pb 锆石定年：俯冲起始记录

• DOI: 10.1029/2020jb020758
• 发表时间: 2021
• 期刊: Journal of Geophysical Research: Solid Earth
• 作者: Rioux, Matthew;Garber, Joshua M.;Searle, Michael;Kelemen, Peter;Miyashita, Sumio;Adachi, Yoshiko;Bowring, Samuel
• 通讯作者: Bowring, Samuel