南极GRV021788橄辉无球粒陨石的岩石学和矿物学特征  

Petrography and mineralogy of the Grove Mountains (GRV) 021788 ureilite from Antarctica

作　　者：梁英[1] 王鹤年[1] 徐伟彪[2] 季峻峰[1] 

机构地区：[1]南京大学内生金属矿床成矿机制研究国家重点实验室南京大学地球科学系,江苏南京210093 [2]中国科学院紫金山天文台,江苏南京210008

出　　处：《地球化学》2006年第1期19-26,共8页Geochimica

基　　金：南京大学内生金属矿床成矿机制研究国家重点实验室开放基金;国家海洋局极地办公室专项基金

摘　　要：橄辉无球粒陨石是一类特殊的无球粒陨石,既具有高度分异的火成特征,又具有原始球粒陨石的特征。南极格罗夫山GRV021788陨石由橄榄石、辉石以及少量的富碳基质、不透明矿物组成,具有橄辉无球粒陨石典型的岩相学和矿物学特征,包括橄榄石晶体三线共点的接触和富镁还原边等。GRV021788的主要矿物的化学成分为:橄榄石Fa23.2～Fa1.5,易变辉石Fs21.2Wo10.6～Fs18.7Wo10.7。橄榄石颗粒有明显的反环带结构,而易变辉石的反环带则不明显。黑色填隙基质富碳,含金刚石和石墨。岩石学和矿物化学特征表明GRV021788是一橄辉无球粒陨石,属单矿(monomict)Ⅰ类(Fa23.2～Fs20.4)橄辉无球粒陨石。陨石的形成机制与多阶段部分熔融-堆积模式较为一致。Ureilite is a particular kind of achondrite. It has not only highly fractionated igneous characteristics, but also primitive chondritic properties. The Grove Mountains （GRV） 021788 meteorite from Antarctica consists of olivine, pyroxene, and a few carbonaceous matrices and opaque minerals. It has petrography and mineralogy of typical ureilites, such as triple junctions and Mg-rich reduction rims of olivines. The mineralogical chemistry of GRV 021788 is characterized by olivine （Fa23.2 -Fa1.5）, and pigeonite （Fs21.2Wo10.6 -Fs18.TWol0.7） Olivine has distinct reverse zoning, while the reverse zoning in pigeonite is less extensive. Dark interstitial matrices are abundant in carbonaceous materials diamond, graphite and so on. Characteristics of petrology and mineralogical chemistry indicate that GRV 021788 is a type- I monomict ureilite （Fa23.2 -Fs20.4）. The origin of this meteorite is probably compatible with a partial melting cumulation model.

关 键 词：南极陨石 橄辉无球粒陨石 反环带结构 富碳基质 陨石成因 

分 类 号：P691[天文地球—地质学] P581