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Chinese Academy of Sciences Institutional Repositories Grid
Mineralogy of silicate inclusions of the Colomera IIE iron and crystallization of Cr-diopside and alkali feldspar from a partial melt

文献类型:期刊论文

作者Takeda, H; Hsu, WB; Huss, GR
刊名GEOCHIMICA ET COSMOCHIMICA ACTA
出版日期2003-06-01
卷号67期号:12页码:2269-2287
关键词LODRANITE PARENT BODY CHEMICAL CLASSIFICATION IAB IRON METEORITES PETROLOGY ELEMENT AGES DIFFERENTIATION CHEMISTRY EVOLUTION
ISSN号0016-7037
英文摘要We studied the mineralogy, mineral chemistry, and compositions of 48 interior silicate inclusions and a large K-rich surface inclusion from the Colomera HE iron meteorite. Common minerals in the interior silicate inclusions are Cr diopside and Na plagioclase (albite). They are often enclosed by or coexist with albitic glasses with excess silica and minor Fe-Mg components. This mineral assemblage is similar to the "andesitic" material found in the Caddo County IAB iron meteorite for which a partial melt origin has been proposed. The fairly uniform compositions of Cr diopside (Ca44Mg46Fe10) and Na plagioclase (Or(2.5)Ab(90.0)An(7.5) to Or(3.5)Ab(96.1)An(0.4)) in Colomera interior inclusions and the angular boundaries between minerals and metal suggest that diopside and plagioclase partially crystallized under near-equilibrium conditions from a common melt before emplacement into molten metal. The melt-crystal assemblage has been called "crystal mush." The bulk compositions of the individual composite inclusions form an array between the most diopside-rich inclusion and plagioclase. This is consistent only with a simple mechanical mixing relationship, not a magmatic evolution series. We propose a model in which partly molten metal and crystal mush were mixed together by impact on the HE parent body. Other models involving impact melting of the chondritic source material followed by growth of diopside and plagioclase do not easily explain near equilibrium growth of diopside and Na plagioclase, followed by rapid cooling. In the K-rich surface inclusion, K feldspar, orthopyroxene, and olivine were found together with diopside for the first time. K feldspar (sanidine, Or(92.7)Ab(7.2)An(0.1) to Or(87.3)Ab(11.0)An(1.7)) occurs in an irregular veinlike region in contact with large orthopyroxene crystals of nearly uniform composition (Ca1.3Mg80.5Fe17.8 to Ca3.1Mg78.1Fe18.9) and intruding into a relict olivine with deformed-oval shape. Silica and subrounded Cr diopside are present within such K-feldspar regions. Some enrichments of the albite component have been detected at the end of curved elongated nodules of K feldspar intruded into the mafic silicates. The textural relationships suggest that a K-rich melt was present. A K-rich melt is neither the first melt of a chondritic system nor a differentiation product of a Na-rich partial melt of chondritic: material. The K-rich material may have originated as a fluid phase that leached K from surrounding materials and segregated by a mechanism similar to that proposed for the Na-rich inclusions. Copyright (C) 2003 Elsevier Science Ltd.
WOS标题词Science & Technology ; Physical Sciences
学科主题Geochemistry & Geophysics
类目[WOS]Geochemistry & Geophysics
研究领域[WOS]Geochemistry & Geophysics
关键词[WOS]LODRANITE PARENT BODY ; CHEMICAL CLASSIFICATION ; IAB IRON ; METEORITES ; PETROLOGY ; ELEMENT ; AGES ; DIFFERENTIATION ; CHEMISTRY ; EVOLUTION
收录类别SCI
语种英语
WOS记录号WOS:000183608300012
公开日期2012-08-08
源URL[http://libir.pmo.ac.cn/handle/332002/4627]  
专题紫金山天文台_天体化学和行星科学实验室
作者单位1.Chiba Inst Technol, Res Inst, Narashino, Chiba 2750016, Japan
2.CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA
3.Acad Sinica, Purple Mt Observ, Nanjing 210008, Peoples R China
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GB/T 7714
Takeda, H,Hsu, WB,Huss, GR. Mineralogy of silicate inclusions of the Colomera IIE iron and crystallization of Cr-diopside and alkali feldspar from a partial melt[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2003,67(12):2269-2287.
APA Takeda, H,Hsu, WB,&Huss, GR.(2003).Mineralogy of silicate inclusions of the Colomera IIE iron and crystallization of Cr-diopside and alkali feldspar from a partial melt.GEOCHIMICA ET COSMOCHIMICA ACTA,67(12),2269-2287.
MLA Takeda, H,et al."Mineralogy of silicate inclusions of the Colomera IIE iron and crystallization of Cr-diopside and alkali feldspar from a partial melt".GEOCHIMICA ET COSMOCHIMICA ACTA 67.12(2003):2269-2287.

入库方式: OAI收割

来源:紫金山天文台

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