甘肃卓尼喇嘛崖洮砚地质特征及成因

甘肃省卓尼县洮砚乡喇嘛崖洮砚位于新堡—洋沙复背斜核部的上泥盆统大草滩组中,矿体呈近SN向展布。本文通过洮砚的组成成分、结构构造、物理性质、化学性质、宝石学特征及成因分析,表明洮砚主要矿物为绢水云母,呈细小鳞片状结构,定向排列,具有富铝系列、伊利石型粘土特征,微量元素及放射性元素均很低的特点;岩石致密,固结程度中等,肖氏硬度为51~56,密度2.75~2.77 g/cm3,饱和吸水率0.45~0.47,孔隙度1.2%~1.3%,粒度0.011~0.053mm,遭受浅的区域变质作用,节理、裂隙发育程度低。

Geological features and genesis of Taoyan in Lama cliff, Zhuoni county, Gansu province

Taoyan lying in Lama cliff of Zhuoni county,Gansu province,is located at upper Devonian Dacaotan group in Xinbao-Yangsha anticlinorium core.The ore body was trending near NS direction.By analyzing the composition,structure,physical and chemical features,gemological characteristics and genesis of Taoyan,the results show that the main mineral of Taoyan is Sericite,which was a small flake-like structure and directional alignment,with Al-rich series,illite-type clay characteristics,and very low contents of trace elements and radioactive elements.The rocks was dense,and the degree of consolidation was moderate,with Shore hardness of 51~56,density of 2.75~2.77 g/cm3,saturated water absorption of 0.45～0.47,1.2~1.3% porosity and particle size 0.011-0.053mm,which were subjected to shallow regional metamorphism.