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首页 > 中国极地考察知识库 > 成果信息库 > 已审查 新疆库木塔格004号陨石球粒类型研究及其在球粒分类体系的应用

新疆库木塔格004号陨石球粒类型研究及其在球粒分类体系的应用

【标题】新疆库木塔格004号陨石球粒类型研究及其在球粒分类体系的应用

【Title】THE RESEARCH OF CHONDRULES TYPES OF KUMTAG 004 CHONDRITE FROM XINJIANG AND THE APPLICATION OF CHONDRULES CLASSIFICATION SCHEMES

【DOI】10.3724/SP.J.1084.2013.00436

【作者】 张川统; 缪秉魁; 贺怀宇

【Author】 Zhang Chuantong ; Miao Bingkui ; He Huaiyu

【期刊】极地研究

【Journal】ADVANCES IN POLAR SCIENCE

【期刊年份】2013

【卷】25

【期】4

【关键词】 球粒分类; 结构; 化学成分; 库木塔格004号陨石

【Keywords】 classification for chondrule; texture; chemical composition; Kumtag 004 chondrite

【摘要】球粒是球粒陨石的主要组分,目前球粒分类体系主要有三种,即结构分类、FeO-SiO2分类和M-FeO-CaO分类。球粒结构分类过于依赖结构与形态,而与化学成分联系不紧密。FeO-SiO2分类体系和M-FeO-CaO分类体系在传统的结构分类体系基础上加入了矿物化学分类参数,这有利于进一步研究太阳星云演化的物理化学过程。但与结构分类相比,很少利用FeO-SiO2和M-FeO-CaO分类体系对陨石球粒进行分类。本次所研究陨石为我国新发现的沙漠陨石富集区——新疆库木塔格沙漠004号陨石(L4,S4,W3),在对其中的球粒进行了详细普查和研究的基础上,分别利用三种分类体系对该陨石中的球粒进行分类,并进一步探讨了FeO-SiO2分类和M-FeO-CaO分类方法优缺点与应用范围。通过对比分析,提出了后两种分类方法的改进意见:针对FeO-SiO2分类体系,提出以硅酸盐中FeO=7.5%(wt%)为I型和II型球粒分界线,SiO2=47%及53%(wt%)为A型、AB型和B型球粒分界线。FeO-SiO2分类体系不仅能应用于斑状球粒,也适用非斑状球粒。对M-FeO-CaO分类体系依据辉石组分(FeO及CaO,单位wt%)对A1型(FeO<1,CaO>1)、A2型(FeO≈1—3,CaO<0.5)、A5型(FeO≈11—14,CaO≈0.3—0.9)和B型(FeO>3,CaO<0.5)球粒的类型区间进行了初步划分。

【Abstract】Chondrules are the main constituents of chondrites. There are 3 main kinds of classification schemes of chondrules currently, i.e., texture, FeO-SiO2 and M-FeO-CaO. The texture classification depends on texture and morphology highly but chemical composition unclosely. The FeO-SiO2 and M-FeO-CaO classification schemes introduce mineral chemical criteria onto traditional texture taxonomic scheme and can further insight into the physical-chemical process occurring in the solar nebula. But the practical applications are too few for the latter two schemes. The chondrules in Kumtag 004 (L4, S4, W3) which from the new desert meteorites enrichment region-Kumtag desert of Xinjiang have been classified base on the three classification schemes after observing structure and analyzing composition. Then we discuss the merit and demerit of the FeO-SiO2 and M-FeO-CaO classification schemes and the application range. For the FeO-SiO2 taxonomic scheme that can apply to porphyritic chondrules as well as non-porhyritic chondrules, wo suggest that FeO=7.5% (wt%) is the boundary between type I and II chondrules and so are 47% and 53%(SiO2, wt%) for type A, AB and B chondrules. A approximate partition is proposed for the type A1(FeO<1,CaO>1), A2(FeO≈1-3,CaO<0.5), A5(FeO≈11-14,CaO≈0.3-0.9) and B(FeO>3,CaO<0.5) chondrules for the M-FeO-CaO classification scheme based on the pyroxene (FeO and CaO, wt%).

【基金/项目】 行星冲击产生的高温高压相变反应:月球火星陨石中后成合晶的研究 ; 广西隐伏金属矿产勘查重点实验室主任基金项目(13-A-01-02) ; 广西研究生教育创新计划资助项目(YCSZ2013074)

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