气候变化领域集成服务门户(CCPortal): Enormous Lithium Isotopic Variations of Abyssal Peridotites Reveal Fast Cooling and Melt/Fluid-Rock Interactions

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DOI	10.1029/2020JB020393
	Enormous Lithium Isotopic Variations of Abyssal Peridotites Reveal Fast Cooling and Melt/Fluid-Rock Interactions
	Liu P.-P.; Liang J.; Dick H.J.B.; Li X.-H.; Chen Q.; Zuo H.-Y.; Wu J.-C.
发表日期	2020
ISSN	21699313
卷号	125 期号:9
英文摘要	Fast diffusing Li isotopes provide important insights into the “recent” transient events or processes for both modern and ancient times, but questions remain concerning the large Li isotopic variations of mantle peridotites, which greatly hampers their usage as a geochemical tracer. This study investigates in situ Li content and isotopic profiles of the constituent minerals of abyssal peridotites from the Gakkel Ridge and Southwest Indian Ridge. The complicated and large variations of Li isotopic profiles in Clinopyroxene (Cpx) and Orthopyroxene (Opx) indicate Li isotopic disequilibrium at millimeter scale. The negative correlations of a wide range of Li contents (0.5 to 6.5 ppm) and δ7Li values (−10 to +20‰) of olivine, Opx and Cpx grains/relicts, trace element zoning of Cpx, the occurrence of plagioclase, olivine serpentinization along cracks, together with numerical modeling demonstrate the observed Li characteristics to be a manifestation of high-temperature mineral-melt Li diffusion during melt impregnation overprinted by low-temperature mineral-fluid Li diffusion during dissolution and serpentinization. The preservation of the Li isotopic diffusion profiles requires rapid cooling of 0.3–5°C/year after final-stage melt impregnation at the Moho boundary, which is consistent with the low temperature at very slow spreadin g ridges caused by conductive cooling. Compared with the well-studied melt-rock interaction process, our study indicates that low-temperature fluid-rock interaction can induce Li diffusion even in the visibly unaltered mineral relicts of partially altered rocks. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	abyssal peridotite; fluid-rock interaction; isotope diffusion; Li isotope; melt-rock interaction
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/187642
作者单位	Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing, China; Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA, United States; Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China; School of Ocean and Earth Science, Tongji University, Shanghai, China; Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing, China
推荐引用方式 GB/T 7714	Liu P.-P.,Liang J.,Dick H.J.B.,et al. Enormous Lithium Isotopic Variations of Abyssal Peridotites Reveal Fast Cooling and Melt/Fluid-Rock Interactions[J],2020,125(9).
APA	Liu P.-P..,Liang J..,Dick H.J.B..,Li X.-H..,Chen Q..,...&Wu J.-C..(2020).Enormous Lithium Isotopic Variations of Abyssal Peridotites Reveal Fast Cooling and Melt/Fluid-Rock Interactions.Journal of Geophysical Research: Solid Earth,125(9).
MLA	Liu P.-P.,et al."Enormous Lithium Isotopic Variations of Abyssal Peridotites Reveal Fast Cooling and Melt/Fluid-Rock Interactions".Journal of Geophysical Research: Solid Earth 125.9(2020).