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
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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 |
推荐引用方式 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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