气候变化领域集成服务门户(CCPortal): Calcium Stable Isotopes of Tonga and Mariana Arc Lavas: Implications for Slab Fluid-Mediated Carbonate Transfer in Cold Subduction Zones

CCPortal

DOI	10.1029/2020JB020207
	Calcium Stable Isotopes of Tonga and Mariana Arc Lavas: Implications for Slab Fluid-Mediated Carbonate Transfer in Cold Subduction Zones
	Wang X.; Wang Z.; Liu Y.; Park J.-W.; Kim J.; Li M.; Zou Z.
发表日期	2021
ISSN	21699313
卷号	126 期号:3
英文摘要	Carbonation of oceanic lithosphere occurs widely during seawater alteration, and subducted carbonated oceanic lithosphere may play a key role in carbon recycling in subduction zones. Here we investigate the Ca isotopic composition of arc lavas from the Tonga rear arc and Mariana arc, western Pacific, to explore the effect of fluid-mediated carbonate transfer in subduction zones. Fresh basalts (0.84 ± 0.01‰, 2sd, n = 3) and dacites (0.84 ± 0.10‰, 2sd, n = 9) from the Tonga rear arc show indistinguishable δ44/40Ca, reflecting negligible Ca isotopic fractionation during differentiation of hydrous arc magmas. More importantly, arc lavas from both the Tonga rear arc (0.84 ± 0.09‰, 2sd, n = 12) and Mariana arc (0.79 ± 0.12‰, 2sd, n = 9) display MORB-like δ44/40Ca values. The MORB-like δ44/40Ca of arc lavas indicates that the carbonates released from altered oceanic lithosphere (AOL) do not significantly modify the Ca isotopic composition of the mantle wedge, although extensive volcanic CO2 degassing at both arcs suggests that slab fluids might introduce abundant carbonate into the depleted mantle wedge. These results could be attributed to a limited Ca budget in the slab fluids added to the mantle wedge and/or homogenization effect of variable δ44/40Ca for the slab fluids. At cold subduction zones, a fraction of carbonates from the AOL may survive during slab dehydration and recycle into the deep mantle. © 2021. American Geophysical Union. All Rights Reserved.
英文关键词	arc lavas; Ca isotopes; carbon recycling; carbonate; subduction zone
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/187315
作者单位	State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Sciences, China University of Geosciences, Wuhan, China; School of Earth and Environmental Sciences, Seoul National University, Seoul, South Korea; Deep-Sea and Seabed Mineral Resources Research Center, Korea Institute of Ocean Science and Technology, Busan, South Korea
推荐引用方式 GB/T 7714	Wang X.,Wang Z.,Liu Y.,et al. Calcium Stable Isotopes of Tonga and Mariana Arc Lavas: Implications for Slab Fluid-Mediated Carbonate Transfer in Cold Subduction Zones[J],2021,126(3).
APA	Wang X..,Wang Z..,Liu Y..,Park J.-W..,Kim J..,...&Zou Z..(2021).Calcium Stable Isotopes of Tonga and Mariana Arc Lavas: Implications for Slab Fluid-Mediated Carbonate Transfer in Cold Subduction Zones.Journal of Geophysical Research: Solid Earth,126(3).
MLA	Wang X.,et al."Calcium Stable Isotopes of Tonga and Mariana Arc Lavas: Implications for Slab Fluid-Mediated Carbonate Transfer in Cold Subduction Zones".Journal of Geophysical Research: Solid Earth 126.3(2021).