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DOI | 10.1016/j.epsl.2021.117111 |
Osmium isotope evidence for rapid melt migration towards the Moho in the Oman ophiolite | |
Klaessens D.; Reisberg L.; Jousselin D.; Godard M.; Aupart C. | |
发表日期 | 2021 |
ISSN | 0012821X |
卷号 | 572 |
英文摘要 | The oceanic crust, covering two-thirds of the Earth's surface, is formed along mid-oceanic ridges by crystallization at shallow levels of melts formed at depth by partial melting of mantle peridotite. Yet, the process of melt transport to the ridge axis remains poorly understood. Ophiolites, which provide a window into the uppermost mantle, contain dunite bodies often interpreted as relics of melt flow conduits, formed by pyroxene dissolution during melt-peridotite interaction. Here, we present structural and geochemical data on peridotites from the southeastern Oman ophiolite where three types of dunite, corresponding to the Moho transition zone (MTZ), the main and basal mantle sections, are identified. We focus on osmium isotopes, which are particularly well-adapted to tracing melt flow through peridotites. Osmium isotope signatures from host harzburgites accord with abyssal peridotite values and do not vary systematically with setting. In contrast, dunite Os compositions depend on structural context. Basal dunites display compositions similar to harzburgite values, while MTZ dunites have highly radiogenic compositions similar to those of the overlying crust, requiring extensive interaction with melts more radiogenic than MORB. Modeling shows that melts percolating through and equilibrating with dunite channels would acquire unradiogenic compositions, inconsistent with the observed Os signatures of MTZ dunites and lower crust. Thus, our findings require melt transport without equilibration with dunite or harzburgite, arguing for rapid or at least chemically isolated melt migration from the mantle source to the Moho. © 2021 Elsevier B.V. |
关键词 | dunitemantlemelt migrationOman ophioliteOsmium isotopes |
英文关键词 | Silicate minerals; Structural geology; Dunite; Harzburgites; Mantle; Melt flow; Melt migration; Melt transports; Oman ophiolite; Osmium isotopes; Radiogenics; Transition zones; Isotopes |
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/203166 |
作者单位 | Centre de Recherches Pétrographiques et Géochimiques, UMR 7358 CNRS - Université de Lorraine, 15 rue Notre Dame des Pauvres, Vandœuvre-lès-Nancy, F-54501, France; Géosciences Montpellier, CNRS, Université de Montpellier, Montpellier, France; Physics of Geological Processes (PGP), The Njord Centre, Dept. of Geosciences, University of Oslo, PO Box 1048, Oslo, N-0316, Norway |
推荐引用方式 GB/T 7714 | Klaessens D.,Reisberg L.,Jousselin D.,et al. Osmium isotope evidence for rapid melt migration towards the Moho in the Oman ophiolite[J],2021,572. |
APA | Klaessens D.,Reisberg L.,Jousselin D.,Godard M.,&Aupart C..(2021).Osmium isotope evidence for rapid melt migration towards the Moho in the Oman ophiolite.Earth and Planetary Science Letters,572. |
MLA | Klaessens D.,et al."Osmium isotope evidence for rapid melt migration towards the Moho in the Oman ophiolite".Earth and Planetary Science Letters 572(2021). |
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