DOI: 10.1016/j.epsl.2021.117111
论文题名: Osmium isotope evidence for rapid melt migration towards the Moho in the Oman ophiolite
作者: Klaessens D. ; Reisberg L. ; Jousselin D. ; Godard M. ; Aupart C.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2021
卷: 572 语种: 英语
中文关键词: dunite
; mantle
; melt migration
; Oman ophiolite
; Osmium 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
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. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/165544
Appears in Collections: 气候变化与战略
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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
Recommended Citation:
Klaessens D.,Reisberg L.,Jousselin D.,et al. Osmium isotope evidence for rapid melt migration towards the Moho in the Oman ophiolite[J]. Earth and Planetary Science Letters,2021-01-01,572