气候变化领域集成服务门户(CCPortal): Grain Size Variations Record Segregation of Residual Melts in Slow-Spreading Oceanic Crust (Atlantis Bank, 57°E Southwest Indian Ridge)

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DOI	10.1029/2020JB020997
	Grain Size Variations Record Segregation of Residual Melts in Slow-Spreading Oceanic Crust (Atlantis Bank, 57°E Southwest Indian Ridge)
	Ferrando C.; France L.; Basch V.; Sanfilippo A.; Tribuzio R.; Boulanger M.
发表日期	2021
ISSN	21699313
卷号	126 期号:4
英文摘要	Beneath slow-spreading ridges, melt bodies are generally considered to represent ephemeral magma reservoirs filled with crystal mushes. Formation of the oceanic crust requires at least partial extraction of melts from these crystal mushes. However, melts collection and extraction are processes yet to be fully constrained. We investigate olivine gabbros from the plutonic section recovered at the IODP Hole U1473A, in the Atlantis Bank Oceanic Core Complex (Southwest Indian Ridge), to unravel (i) the process of melt migration through lower crustal crystal mushes, and (ii) the collection and segregation of melts forming discrete microgabbro intervals. Throughout the Hole, fine- to coarse-grained intervals are widespread in olivine gabbros. Along the contacts, coarse-grained minerals display resorbed grain boundaries against the fine-grained minerals, suggesting partial dissolution by the melt crystallizing the fine-grained material. Coarse-grained plagioclase and clinopyroxene are zoned, showing progressive chemical evolution from more primitive crystal cores to more evolved crystal rims. Fine-grained minerals are unzoned and chemically similar to rims of coarse-grained minerals, indicating a genetic relationship. We attribute significant enrichments in the most incompatible elements of plagioclase and clinopyroxene to a magma evolution process associated with reactive melt migration. As temperature decreased, melts residual from the reactive processes were segregated in magma pockets that ultimately crystallize the fine-grained intervals (microgabbros). We document, for the first time, that these microgabbros are crystallization products of melts modified by reactive melt migration; the melts were extracted from the crystal mush and accumulated into discrete melt-rich zones. This process could have promoted partial extraction of those melts that in turn potentially contribute to Mid Ocean Ridge Basalts erupted at the seafloor. © 2021. American Geophysical Union. All Rights Reserved.
英文关键词	crystal mushes; lower oceanic crust; melt accumulation and extraction; mineral chemistry; reactive porous flow
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/187243
作者单位	Université de Lorraine, CNRS, CRPG, Nancy, France; Dipartimento di Scienze della Terra e dell'Ambiente, Università degli Studi di Pavia, Pavia, Italy
推荐引用方式 GB/T 7714	Ferrando C.,France L.,Basch V.,et al. Grain Size Variations Record Segregation of Residual Melts in Slow-Spreading Oceanic Crust (Atlantis Bank, 57°E Southwest Indian Ridge)[J],2021,126(4).
APA	Ferrando C.,France L.,Basch V.,Sanfilippo A.,Tribuzio R.,&Boulanger M..(2021).Grain Size Variations Record Segregation of Residual Melts in Slow-Spreading Oceanic Crust (Atlantis Bank, 57°E Southwest Indian Ridge).Journal of Geophysical Research: Solid Earth,126(4).
MLA	Ferrando C.,et al."Grain Size Variations Record Segregation of Residual Melts in Slow-Spreading Oceanic Crust (Atlantis Bank, 57°E Southwest Indian Ridge)".Journal of Geophysical Research: Solid Earth 126.4(2021).