10块新疆哈密沙漠陨石的类型及其岩石矿物学特征  

Classification of 10 meteorites from Hami in Xinjiang: Petrology and mineralogy

作　　者：赖永旺 王桂琴[1] 

机构地区：[1]中国科学院广州地球化学研究所同位素地球化学国家重点实验室,广东广州510640 [2]中国科学院大学,北京100049

出　　处：《地球化学》2015年第3期301-310,共10页Geochimica

基　　金：国家自然科学基金重大项目(41490631)

摘　　要：沙漠是除南极地区之外的另一陨石样品的主要来源地。我国拥有面积辽阔的沙漠，为陨石的收集提供了有利的地理条件。2013年5月，在首次新疆库姆塔格沙漠陨石考察中，发现并收集到46块陨石样品，确定了3个陨石富集区：Hami、Alatage Mountain（AM）和Kumtag。对其中的10块代表性陨石样品进行了矿物岩石学研究，在此基础上确定了它们的化学群、岩石类型、冲击变质程度和风化程度。10块库姆塔格陨石均为普通球粒陨石，其中1块样品Kumtag014（Fa摩尔百分比为9．1～48．3，相对标准偏差PMD为51．0；Fs摩尔百分比为2．8～30．3，PMD为54．2）属于非平衡型L群。依据橄榄石Fa的PMD将其进一步划分为3．4亚型，属于相当原始的球粒陨石样品。另外9块经历了明显的热变质作用，为5型普通球粒陨石，包括7块L群（Fa22．6～25．9，Fs17．6-21．4）和2块H群（Fa18．2～20．8，Fs16．0～17．8）。这些陨石的冲击变质程度：5块S3型，4块S2型，1块S1型；风化程度：3块W1型，6块W2型，1块W3型。In addition to the Antarctic, desert is the main source of meteorites. China has a vast desert area which provides favorable geographical conditions for collection of meteorites. In total 46 meteorite samples were found and collected in Kumtag, Xinjiang in May 2013, and this is the first time for organized meteorites hunting in desert conducted by specialists. Three meteoritic concentration areas were ascertained in our search scope： Hami, Alatage Mountain （AM） and Kumtag. In this study, 10 representative meteorites were selected from these three areas, and were classified in terms of chemical group, petrographic type, shock stage and weathering scale based on their petrography and mineral chemistry. These ten desert meteorites were found to be all ordinary chondrite meteorites. Among them Kumtag014 （Fa 9.1-48.3, PMD 51.0; Fs 2.8-30.3, PMD 54.2） is an unequilibrated ordinary chondrite, belonging to L3.4 group, while the other nine equilibrated ordinary chondrites belong to type 5, covering L groups （Fa 22.6-25.9, Fs 17.6-21.4） for 7 samples and H groups （Fa 18.2-20.8, Fs 16.0-17.8） for 2 samples. The shock metamorphic stages for most chondrites are generally low： five being $3, four $2 and one S 1. The weathering degrees for these chondrites are mostly limited： W1 for three of them, W2 for six and only one for W3.

关 键 词：沙漠陨石 陨石分类 岩石学 矿物成分 

分 类 号：P58[天文地球—岩石学] P185.83[天文地球—地质学]