摘要
对南极格罗夫山蓝冰地区收集的23个陨石进行了系统研究。经激光共聚焦显微镜观察,未查出碳质球粒陨石。经电子探针鉴定,也未发现顽火辉石球粒陨石。系统的研究确定这些陨石均为普通球粒陨石。运用X射线能谱仪进行全视域元素成分面分析方法,获得了23个陨石的化学成分。应用陨石中SiO_2、∑FeO、MgO、CaO的含量进行图解对比,划分出陨石的化学群,取得了初步的结果。又以电子探针测得的橄榄石、辉石矿物化学成分,采用Fa-Fs图解法进行化学群分类。这两种方法对23个陨石化学群的划分,取得了较为一致结果。陨石岩石类型的确定,主要根据陨石中球粒及基质的特征,参考其它标志,如橄榄石成分、辉石的结构、长石的特征等进行分类,效果较好。对于岩石类型为第3类的非平衡陨石,由于矿物成分变化较大,并可能有水等易挥发成分的存在,其化学群的划分不易确定。
Twenty-three meteorites collected from Blue Ice Area, Grove Mountains, Antarctica have been studied systematically. Observations by laser confocal microscope and determinations by electron probe revealed that neither carbonaceous chondrite nor enstatite chondrite were found among these meteorites. All 23 meteorites studied belong to ordinary chondrites.
With the help of energy dispersive X-ray spectrometer installed in SEM large area chemical analytical data of the 23 chondrites were obtained from sections of these samples. According to SiO2 , ∑FeO, MgO and CaO content distribution in the histograms, chemical groups of the 23 chondrites were tentatively divided. On the basis of distribution of olivines and pyroxenes determined by electron probe in the Fa - Fs plot chemical groups of the 23 chondrites were divided, too. The two results for the 23 chondrites are almost identical.
Petrologic types for the 23 chondrites are ascertained mainly based on the property of chon-drules and matrix structures of the chondrites, as well as the composition of olivines, structures of pyroxenes and characteristics of feldspars, and so on. But, for the Type 3 of unequilibrated meteorites, its difficult to determine their chemical groups exactly as the mineral composition varies in a large range and probably there is water in the meteorites.
出处
《极地研究》
CAS
CSCD
2002年第4期308-319,共12页
Chinese Journal of Polar Research
