顽辉石陨石中A、B矿的微量元素化学意义

MINERALS A AND B IN ENSTATITE METEORITES AND THEIR TRACE ELEMENT CHEMISTRY

运用电子探针和中子活化分析方法测定了清镇（EH3）和Bustee顽辉石无球粒陨石中含铬硫化物相（A、B矿）的组成和微量元素含量。正如早期的报告结果，电子探针分析结果不足100％，表明有相当含量的轻元素（z＜10）存在。综合对比文献数据，对于A矿物，缺失组分约10％，B矿物约为20％或约为28％。这些相具有高的Sc含量（清镇样品分别为61μg／g和45μg／g，Bustee样品为32μg／g）。Bustee样品还具有极端高含量Eu（320μg／g）和高Ti含量（A和B矿物分别会Ti1．18％和0．91％），而在清镇陨石的这些相中，Ti含量却很低，陨硫铁中Ti含量具有相似的分布。根据这些结果，讨论了顽辉石球粒陨石和无球粒陨石的母体成因联系。

Mineral and trace element compositions of Cr-sulfides, i. e. the partially characterized minerals which Ramdohr (1963 ) termed 'minerals A and B', have been determined in the Qingzhen (EH3) chondrite and the Bustee aubrite by electron microprobe and instrumental neutron activation techniques. As with previous determinations, our quantitative microprobe analyses do not sum to 100%, suggesting the presence of significant amounts of elements with z＜10. A literature survey indicates that the missing mass tends to be 10% for mineral A and either 20% or 28%for mineral B. Samples consisting of a mixed intergrowth of these phases contain high Sc (61 μg/g and 45μg/g for two samples of the Qingzhen and 32μg/g for the Bustee) and in the Bustee they also contain high Eu (32μg/g) and Ti (1. 18 wt% in A and 0. 91 wt % in B), but this is not the case for the E chondrite. Troilite displays similar differences in Ti content in the aubrites and E chondrites. The relationship between enstatite chondrites and aubrites is discussed based on the trace element abundances of minerals A and B in enstatite meteorites.