郭家岭花岗闪长岩中黑云母的成因矿物学研究

Genetic Mineralogy of Biotite from Guojialing Granokiorite

通过对郭家岭花岗闪长岩中黑云母的形态、成分及穆斯堡尔谱等分析，表明其具深棕褐色到淡黄色多色性、云母律双晶、波状消光、集合体呈六方锥状，在不稳定、氧化条件下形成，并且富Ｆｅ：、Ｆｅ￣（３＋）、Ｆ￣－贫ＯＨ￣－。其蚀变产物常为绿泥石和黄铁矿。以上特征表明其对形成金矿有利。

According to an analysis of biotite from Guojialing granokiorite in such aspects as its conimon characteristics shape,composition,genetic diagram:and Mossbauer spectra,it is shown that this mineral,rich in Fe,Fe￣(3+),F￣- and Mg and deficient in OH￣-,Was formed under an unstable and oxidized condition.The projoctions of its chemical composition fall into the diorite region,granite region as well as near the granodiorite and adamellite ragion,sugge-sting that a part of this mineral is primary biotite in granodiorite and the other part is local remelting relic bitotite in biotite leptynite of Archean Jiaodong Group whose gold content is the highest(28.23×10￣(-9)).After its formation,biotite underwent tectonic activity and alteration,forming chlorite and pyrite.All this shows that the formation condition and compositional cbaractoristics of biotite are favorable for gold metallogenesis i.e.,GuojialiDg granodiorito,is favorable for the formation of gold deposits, Before 1986,people had all thought that the Guojialing ghranodiorite was unfavorable for gold metallization,and hence drillirug and mining were always stopped whe-rever the work reached the Guojialing granodiorite. Ncvertheless,our research has shown that this granodiorite body could form ore deposits,even rich ones,as is substantiated by the discovery of the.Jiehe gold deposit in this body.