气候变化领域集成服务门户(CCPortal): Noble gas isotopic compositions of seamount lavas from the central Chile trench: Implications for petit-spot volcanism and the lithosphere asthenosphere boundary

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DOI	10.1016/j.epsl.2020.116611
	Noble gas isotopic compositions of seamount lavas from the central Chile trench: Implications for petit-spot volcanism and the lithosphere asthenosphere boundary
	Yamamoto J.; Hirano N.; Kurz M.D.
发表日期	2020
ISSN	0012821X
卷号	552
英文摘要	We report new noble gas isotopic compositions of submarine basaltic glasses sampled from two seamounts discovered offshore of Chile, and inferred to have erupted as petit-spot volcanoes near the Juan Fernández hotspot. The samples have 3He/4He of 1–15 times atmosphere (Ra). Their neon isotope compositions are similar to those of the Hawaiian Islands and Réunion Island. Their 40Ar/36Ar range from atmospheric to 2300. Although the lavas are likely to be influenced by a hotspot-related component, the cause of the 3He/4He variation must be clarified to ascertain the mantle source. Variations in 3He/4He are not attributable to processes occurring at the Earth's surface such as degassing fractionation, mixing with atmosphere dissolved in seawater, or in-situ post-eruptive addition of 4He. A combination of the Ne-Ar isotope ratios corrected for atmospheric influence and He isotope ratios indicates that the noble gas isotopes of the lavas are a mixture of a hotspot magma, MORB-source, and radiogenic components. The lower 3He/4He are attributed to assimilation with the oceanic lithosphere, suggesting that the pristine 3He/4He of the lavas is hotspot-like. These features can be interpreted as indicating that part of the Juan Fernández plume infiltrated the lithosphere–asthenosphere boundary (LAB), and that the ponding magma has erupted as petit-spot volcanoes because of plate bending. The noble gas data indicate that LAB can be a reservoir for exotic melts, which might have lubricated plate tectonics. © 2020
关键词	crustal assimilation Juan Fernández Islands lithosphere–asthenosphere boundary noble gas isotopic ratio petit-spot
英文关键词	Earth atmosphere; Isotopes; Offshore oil well production; Submarine geology; Volcanoes; Basaltic glass; Central Chile; Earth's surface; Hawaiian Islands; Lithosphere-asthenosphere boundary; Noble gas isotopes; Noble gas isotopic composition; Oceanic lithosphere; Inert gases; asthenosphere; basalt; crustal structure; isotopic composition; lava; lithosphere; noble gas; seamount; trench; volcanic eruption; volcanism; Chile; Juan Fernandez Islands; Filicophyta
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/202977
作者单位	The Hokkaido University Museum, Nishi 8, Kita 10, Kita-ku, Sapporo, 060-0810, Japan; Center for Northeast Asian Studies, Tohoku University, 41 Kawauchi, Aoba-ku, Sendai, 980-8576, Japan; Woods Hole Oceanographic Institution, Woods Hole, MA 02543, United States
推荐引用方式 GB/T 7714	Yamamoto J.,Hirano N.,Kurz M.D.. Noble gas isotopic compositions of seamount lavas from the central Chile trench: Implications for petit-spot volcanism and the lithosphere asthenosphere boundary[J],2020,552.
APA	Yamamoto J.,Hirano N.,&Kurz M.D..(2020).Noble gas isotopic compositions of seamount lavas from the central Chile trench: Implications for petit-spot volcanism and the lithosphere asthenosphere boundary.Earth and Planetary Science Letters,552.
MLA	Yamamoto J.,et al."Noble gas isotopic compositions of seamount lavas from the central Chile trench: Implications for petit-spot volcanism and the lithosphere asthenosphere boundary".Earth and Planetary Science Letters 552(2020).