28块南极陨石的类型研究

本文研究的28块陨石,均为我国第16次南极科学考察队,在南极格罗夫山地区回收。由于样品量有限,每个样品仅有一个光簿片。利用透反两用的偏光显微镜,进行陨石结构,矿物组成等一些现象观察。它们都是石质陨石,有球粒陨石和无球粒陨石。根据球粒发育程度,分为五种类型。用电子探针分析陨石中矿物的化学成份。有两块为无球粒陨石,GRV 99018为钙长辉长无球粒陨石,GRV 99027为橄辉无球粒陨石。利用Dodd(1981)和Wasson(1985)球粒陨石化学群分类原则,将26块普通球粒陨石进行化学群的分类,两者划分的结果基本吻合。前者H群有6块,L群有9块,LL群有8块,另3块陨石近于L群(GRV 99019,GRV 99021,GRV99026)。后者H群有5块,GRV 99010近于L群,它可为H/L,L群有9块,L/LL群有2个,LL群有6块,而GRV 99019,GRV 99021和GRV 99026三块陨石与三个群的数据相差较大,它们属于非平衡球粒陨石,可能是L。26块普通球粒陨石,有5个为非平衡普通球粒陨石,其它21个为平衡球粒陨石。21个平衡普通球粒陨石的岩石类型,主要为4—6。

STUDIES ON THE TYPES OF 28 ANTARCTIC METEORITES

The 28 Antarctic meteorites have been collected for the second time from the Grove Mountains of East Antarctica, during the 16th Chinese National Antarctic Research Expedition in 1999-2000 austral season. The 28 meteorites are all stones. According to the chondrule growing the meteorites can be divided into 5 types. GRV 99018 and GRV 99027 are achon-drites, other 26 meteorites are ordinary chondrites. These meteorites belong to different chemical groups ; H-group 5 , H/L-group 1, L-group have 9 , L/LL-group 2, LL-group 6, and L-group 3. Their petrologic types are: uneqquilibrated ordinary chondrites 5, the eqquilibrated ordinary chondrites 21. The majority are of types 4-6.