地学前缘 ›› 2014, Vol. 21 ›› Issue (6): 92-101.DOI: 10.13745/j.esf.2014.06.010

• 论文 • 上一篇    下一篇

6块新回收沙漠陨石的矿物岩石学特征及类型划分

 戴德求, 杨荣丰, 陈新跃   

  1. 1. 湖南科技大学 地质研究所，湖南 湘潭 411201 2. 中国科学院 地球化学研究所，贵州 贵阳 550002 3. 页岩气资源利用湖南省重点实验室，湖南 湘潭 411201
  • 收稿日期:2013-11-26 修回日期:2014-04-10 出版日期:2014-11-15 发布日期:2014-11-15
  • 作者简介:戴德求(1976—），男，博士，副教授，地球化学专业，主要从事陨石学和天体化学研究。E-mail:ddqygf@163.com
  • 基金资助:

    国家自然科学基金项目(41103032)；中国博士后基金项目(2011M501423)；贵州省基金项目(2011GZ40851)

The petrography, mineral chemistry and classification of 6 new desert meteorites collected from Xinjiang

  • Received:2013-11-26 Revised:2014-04-10 Online:2014-11-15 Published:2014-11-15

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摘要：

干旱沙漠地区与南极冰盖均有利于陨石样品保存。2013年4—5月，通过首次新疆哈密沙漠陨石考察，回收了陨石样品47块。文中报导其中6块样品的矿物岩石学特征，并划分它们的化学岩石类型。Arlatager004、006、0014、0022和TuzLeik001等5块样品主要由橄榄石、辉石、长石、铁镍金属和陨硫铁组成，具有典型的普通球粒陨石岩石结构特征，其球粒结构不明显，表明经历过较强的热变质，岩石类型划分为5型；根据样品中橄榄石Fa值,低钙辉石Fs值和样品的金属含量等，将Arlatager004、006、0014、0022划分为L5型普通球粒陨石；TuzLeik001划分为H5型普通球粒陨石。Kumtag005具有典型的球粒结构，结合橄榄石Fa值和低钙辉石Fs值以及岩石学特征，将其划分为L3型普通球粒陨石。根据橄榄石Fa值与其百分标准平均方差(PMD)之间的关系，将Kumtag005的岩石类型亚型划分为L 3.4。这6块样品代表了3个化学群，结合该地区回收到的其他陨石分析结果，表明新疆哈密沙漠是一个新的陨石富集区，这些沙漠陨石的发现和研究，必将极大促进中国陨石学和天体化学的发展。

 

关键词: 沙漠陨石, 岩石学特征, 矿物化学组成, 类型, 新疆

Abstract:

Meteorite samples can be better preserved in Antarctic ice sheet and arid desert regions. Fortyseven desert meteorites were collected from Xinjiang during the meteorite expedition since April to May, 2013. Petrography and mineral chemistry of the 6 samples of them have been studied, in order to determine their chemicalpetrographic types. Modal compositions of the Arlatager 004, 006, 0014, 0022 and TuzLeik001 meteorites are similar, mainly consisting of olivine, lowCa pyroxene, metallic FeNi and troilite. Due to intensive thermal metamorphism the spherulitic textures in the chondrules are poorly defined, with only a few fragments remaining spherulitic. The olivine and lowCa pyroxene in these meteorites are similar in composition, which in some degree reflects the thermodynamic equilibrium during their development. According to the structures of chondrules and mineral chemistry there are 5 petrographic types to be classified. The four meteorite samples (Arlatager 004, 006, 0014 and 0022) are classified into chemical group L, and TuzLeik001 is classified into chemical group H. Kumtag005 meteorite sample shows typical spherulitic texture, combined with its Fa value in olivine and ferrosilite content (Fs) in low Ca pyroxene and its petrographical features,it is assigned to common chondrite of L3 type.Based on Percent Mean Deviation (PMD) of Fa content of olivine and its correction with petrographic subtype of unequilibrated meteorites, Kumtag005 is subdivided as L3.4. The 6 samples of meteorites belong to 3 chemical groups, combining  the other analytical results of meteorites collected from this region, it is suggested that the desert of Hami in Xinjiang is likely a new meteoriteenriched region. The collection and study of desert meteorite will help to promote the development of meteoritics and cosmochemistry in China.

 

Key words: desert meteorite, petrography, mineral chemistry, classification, Xinjiang

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