气候变化领域集成服务门户(CCPortal): Petromagnetic Characteristics of Serpentinization and Magnetite Formation at the Zedang Ophiolite in Southern Tibet

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DOI	10.1029/2020JB019696
	Petromagnetic Characteristics of Serpentinization and Magnetite Formation at the Zedang Ophiolite in Southern Tibet
	Li Z.; Moskowitz B.M.; Zheng J.; Xiong Q.; Zhou X.; Yang J.; Zhang Y.; Liu Q.
发表日期	2020
ISSN	21699313
卷号	125 期号:9
英文摘要	Variably serpentinized peridotites from the Zedang ophiolite in southern Tibet were magnetically and petrologically examined to understand the serpentinization process and evaluate the origin of magnetic anomalies in ultramafic-hosted tectonic settings. Magnetite occurs in the serpentine and brucite veins and is identified as the dominant magnetic carrier by thermomagnetic and petrological analyses. The magnetic susceptibility increases rapidly from <0.001 to ~0.02 SI for the <50% serpentinized samples followed by nearly constant values of 0.02–0.03 SI above 50% serpentinization. This transition corresponds with the formation of Fe-poor serpentine mesh (2–3 wt% FeO) and magnetite in the early stages and the replacement of mesh center olivine by Fe-rich serpentine (4–5 wt% FeO) without magnetite in the late stages. Brucite veins occur in the 50–70% serpentinized samples and indicate serpentinization temperatures from ~250 to <100°C. The serpentinization may initiate at an oceanic spreading ridge center under high temperatures (>250–300°C) to produce magnetite and subsequently continue at lower temperatures (<200–250°C) in near-seafloor settings and limit the magnetite formation, possibly associated with ophiolite emplacement. These serpentinized peridotites have higher magnetization intensities (average 2.26 Am−1) than dolerite dykes and basaltic volcanics (mostly <1 A m−1) in the area and should be the major source of aeromagnetic highs in the south Tibetan ophiolite belt. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	magnetite formation; rock magnetism; serpentinization; Yarlung-Zangbo suture; Zedang ophiolite
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/187629
作者单位	Hubei Subsurface Multi-scale Imaging Key Laboratory, Institute of Geophysics and Geomatics, China University of Geosciences, Wuhan, China; Department of Earth and Environmental Sciences and Institute for Rock Magnetism, University of Minnesota, Twin Cities, Minneapolis, MN, United States; State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Sciences, China University of Geosciences, Wuhan, China; Institute of Geology, Chinese Academy of Geological Sciences, Beijing, China; School of Geophysics and Information Technology, China University of Geosciences, Beijing, China
推荐引用方式 GB/T 7714	Li Z.,Moskowitz B.M.,Zheng J.,et al. Petromagnetic Characteristics of Serpentinization and Magnetite Formation at the Zedang Ophiolite in Southern Tibet[J],2020,125(9).
APA	Li Z..,Moskowitz B.M..,Zheng J..,Xiong Q..,Zhou X..,...&Liu Q..(2020).Petromagnetic Characteristics of Serpentinization and Magnetite Formation at the Zedang Ophiolite in Southern Tibet.Journal of Geophysical Research: Solid Earth,125(9).
MLA	Li Z.,et al."Petromagnetic Characteristics of Serpentinization and Magnetite Formation at the Zedang Ophiolite in Southern Tibet".Journal of Geophysical Research: Solid Earth 125.9(2020).