气候变化领域集成服务门户(CCPortal): Timing of Magnetite Growth Associated With Peridotite-Hosted Carbonate Veins in the SE Samail Ophiolite, Wadi Fins, Oman

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DOI	10.1029/2019JB018632
	Timing of Magnetite Growth Associated With Peridotite-Hosted Carbonate Veins in the SE Samail Ophiolite, Wadi Fins, Oman
	Cooperdock E.H.G.; Stockli D.F.; Kelemen P.B.; de Obeso J.C.
发表日期	2020
ISSN	21699313
卷号	125 期号:5
英文摘要	Carbonate-altered peridotite are common in continental and oceanic settings and it has been suggested that peridotite-hosted carbonate represent a significant component of the carbon-cycle and provide an important link in the CO2 dynamics between the atmosphere, hydrosphere, and lithosphere. The ability to constrain the timing of carbonate and accessory phase growth is key to interpreting the mechanisms that contribute to carbonate alteration, veining, and mineralization in ultramafic rocks. Here we examine a mantle section of the Samail ophiolite exposed in Wadi Fins in southeastern Oman where the peridotite is unconformably overlain by Late Cretaceous-Paleogene limestone and crosscut by an extensive network of carbonate veins and fracture-controlled alteration. Three previous 87Sr/86Sr measurements on carbonate vein material in the peridotite produce results consistent with vein formation involving Cretaceous to Eocene seawater (de Obeso & Kelemen, 2018, https://doi.org/10.1098/rsta.2018.0433). We employ (U-Th)/He chronometry to constrain the timing of hydrothermal magnetite in the calcite veins in the peridotite. Magnetite (U-Th)/He ages of crystal sizes ranging from 1 cm to 200 μm record Miocene growth at 15 ± 4 Ma, which may indicate (1) fluid–rock interaction and carbonate precipitation in the Miocene, or (2) magnetite (re)crystallization within pre-existing veins. Taken together with published Sr-isotope values, these results suggest that carbonate veining at Wadi Fins started as early as the Cretaceous, and continued in the Miocene associated with magnetite growth. The timing of hydrothermal magnetite growth is coeval with Neogene shortening and faulting in southern Oman, which points to a tectonic driver for vein (re)opening and fluid-rock alteration. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	magnetite; Oman; ophicarbonate; serpentinite; U-Th/He thermochronology; Wadi Fins
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/187881
作者单位	Department of Geological Sciences, The University of Texas at Austin, Austin, TX, United States; Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, United States; Now at Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States; Department of Earth and Environmental Sciences, Columbia University, New York, NY, United States
推荐引用方式 GB/T 7714	Cooperdock E.H.G.,Stockli D.F.,Kelemen P.B.,et al. Timing of Magnetite Growth Associated With Peridotite-Hosted Carbonate Veins in the SE Samail Ophiolite, Wadi Fins, Oman[J],2020,125(5).
APA	Cooperdock E.H.G.,Stockli D.F.,Kelemen P.B.,&de Obeso J.C..(2020).Timing of Magnetite Growth Associated With Peridotite-Hosted Carbonate Veins in the SE Samail Ophiolite, Wadi Fins, Oman.Journal of Geophysical Research: Solid Earth,125(5).
MLA	Cooperdock E.H.G.,et al."Timing of Magnetite Growth Associated With Peridotite-Hosted Carbonate Veins in the SE Samail Ophiolite, Wadi Fins, Oman".Journal of Geophysical Research: Solid Earth 125.5(2020).