接近于铁橄榄石端员组份的铁橄榄石集合体的发现及其初步研究

The Discovery and Preliminary Study of Fayalite Aggregates with Composition Approaching the End Member of Fayalite

铁橄榄石集合体为无根岩石。外观呈铁黑色,风化面呈亮栗褐色。本文对铁橄榄石集合体的形态特征、物理性质和化学成分进行了研究。通过化学式的计算,其化学式为:(Mg_(0.0168)Fe_(0.9802)Mn_(0.003))_2[SiO_4],证明其为铁橄榄石的端员组份。此外,还对其进行了穆斯堡尔谱分析、X射线粉晶衍射分析和红外光谱分析。其穆斯斑堡尔谱分析结果与人工合成的铁橄榄石数据相近,它的衍射数据及计算的晶胞参数也与JCPDS所提供的标准数据非常接近,这些进一步证明了铁橄榄石集合体的成分接近于铁橄榄石端员组份。

Fayalite aggregate is a roofless rock black in color and consists almost exclusively of fayalite——(Mg_(0..169) Fe_(0.9802)Mn(0.003)_2 [SiO_4]. The crystals are tabular and columnar in form with the largest grain size reaching 10 mm. The aggregate shows over-cooling texture with dendrite. In this paper, systematically mineralogic data are given about this rare fayalite whose composition approaches the end and member component of fayalite.