气候变化领域集成服务门户(CCPortal): High-Precision U-Pb Zircon Dating of Late Magmatism in the Samail Ophiolite: A Record of Subduction Initiation

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DOI	10.1029/2020JB020758
	High-Precision U-Pb Zircon Dating of Late Magmatism in the Samail Ophiolite: A Record of Subduction Initiation
	Rioux M.; Garber J.M.; Searle M.; Kelemen P.; Miyashita S.; Adachi Y.; Bowring S.
发表日期	2021
ISSN	21699313
卷号	126 期号:5
英文摘要	Understanding the tectonic setting in which ophiolites form is necessary to determine how they can be used to study ocean spreading and subduction zone processes. Here, we present high-precision U-Pb zircon dates and Sm-Nd isotopic data from two late magmatic series in the Samail ophiolite in Oman and the United Arab Emirates (UAE), which constrain its tectonic development. Volcanic rocks in the ophiolite record a progression from MORB-like V1 lavas to subduction-related V2 lavas. Plutonic rocks related to V2 magmatism yielded 206Pb/238U dates of 95.557 ± 0.063–95.289 ± 0.067 Ma. A second late magmatic series consists of felsic dikes and sills that intermittently intrude the upper mantle and are attributed to melting of a subducting slab. These dikes in Oman range from 95.201 ± 0.032 to 94.95 ± 0.10 Ma, with εNd(t) = −5.05 to −1.63. A single dike, attributed to V2 magmatism, has a higher εNd(t) = 7.35 and a date of 95.478 ± 0.032 Ma. Similar intrusions in the UAE are younger, ranging from 94.119 ± 0.057 to 90.998 ± 0.052 Ma. Our new and existing data indicate the following timeline of ophiolite formation during subduction initiation: (1) Initial sole metamorphism at ≥96.2 Ma; (2) Formation of the crust through primarily decompression-related V1 magmatism from 96.1 to 95.6 Ma; (3) V2 magmatism related to H2O-fluxed mantle melting from 95.6 to 95.2 Ma; and (4) Intrusion of slab-derived felsic dikes from 95.2 to 95.0 Ma. The temporal progression of magmatism is similar to the timescales of subduction initiation predicted by geodynamic models and observed in the Izu-Bonin-Mariana forearc. © 2021. American Geophysical Union. All Rights Reserved.
英文关键词	Oman; ophiolite; Samail; subduction initiation; zircon
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187160
作者单位	Department of Earth Science, University of California, Santa Barbara, CA, United States; Earth Research Institute, University of California, Santa Barbara, CA, United States; Department of Geosciences, The Pennsylvania State University, University Park, PA, United States; Department of Earth Sciences, University of Oxford, Oxford, United Kingdom; Department of Earth and Environmental Studies, Columbia University, Lamont Doherty Earth Observatory, Palisades, NY, United States; Hokkaido Research Center of Geology, Ebetsu, Japan; Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, Abiko, Chiba, Japan; Department of Earth, Atmospheric and Planetary Science, Massachusetts Institute of Technology, Cambridge, MA, United States
推荐引用方式 GB/T 7714	Rioux M.,Garber J.M.,Searle M.,et al. High-Precision U-Pb Zircon Dating of Late Magmatism in the Samail Ophiolite: A Record of Subduction Initiation[J],2021,126(5).
APA	Rioux M..,Garber J.M..,Searle M..,Kelemen P..,Miyashita S..,...&Bowring S..(2021).High-Precision U-Pb Zircon Dating of Late Magmatism in the Samail Ophiolite: A Record of Subduction Initiation.Journal of Geophysical Research: Solid Earth,126(5).
MLA	Rioux M.,et al."High-Precision U-Pb Zircon Dating of Late Magmatism in the Samail Ophiolite: A Record of Subduction Initiation".Journal of Geophysical Research: Solid Earth 126.5(2021).