大悟县杨新岩铍矿点含铍矿物赋存状态与成因研究  

Occurrence and Genesis of Beryllium Bearing Mineralsin Yangxinyan Beryllium Ore Spot in Dawu County

作　　者：钟石玉 熊意林 杨成 李书涛 屠江海 石先滨 胡太平 Zhong Shiyu;Xiong Yilin;Yang Cheng;Li Shutao;Tu Jianghai;Shi Xianbin;Hu Taiping(Hubei Geological Survey,Wuhan,Hubei 430034;ixth Geological Brigade of Hubei Geological Bureau,Xiaogan,Hubei 432000)

机构地区：[1]湖北省地质调查院,湖北武汉430034 [2]湖北省地质局第六地质大队,湖北孝感432000

出　　处：《资源环境与工程》2020年第4期518-524,共7页Resources Environment & Engineering

基　　金：2018年度湖北省国土资源科研计划项目——桐柏—大别山地区碱性花岗岩稀有金属成矿作用研究,项目编号ETZ201807A08。

摘　　要：杨新岩铍矿点位于大悟县娘娘顶钨铍矿区内,共圈出了2个铍矿体,均产于娘娘顶花岗岩体与红安岩群黄麦岭组地层接触界面处钠化花岗岩中。大部分铍矿石表面可见独特的黑褐色铁锌锰质皮壳,Be平均品位约为0.05%。运用光薄片岩矿鉴定、电子探针分析、扫描电镜等测试手段,对铍矿石含铍矿物的赋存状态进行研究,发现矿石中含Be矿物为锌日光榴石,含量为0.13%~0.35%,锌日光榴石内含有少量Fe、Mn;锌日光榴石主要与低计数率部位连生,表明锌日光榴石多赋存于岩石裂隙及孔洞内,推测可能为后期变质成因。笔者认为,杨新岩铍矿体为花岗质岩浆热液沿娘娘顶花岗岩体与黄麦岭组地层之间接触面上侵,经岩浆气液双交代作用所形成。娘娘顶花岗岩为南华纪侵入岩,仅为赋矿围岩。矿区内铍成矿作用主要发生于燕山期,娘娘顶花岗岩体之下很可能存在有隐伏的与Be成矿关系紧密的燕山晚期小花岗岩体,为铍矿的形成提供了成矿热液与成矿物质。Yangxinyan beryllium ore spot is located in Niangniangding Tungsten-beryllium mining area in Dawu county.Two beryllium orebodies are delineated,both of which occur in sodium granite at the contact interface between Niangniangding granite body and Huangmailing formation of Hongan group.On the surface of most beryllium ores,the unique black brown Fe-Zn-Mn crust can be seen,and the average grade of be is about 0.05%.In this paper,the occurrence of beryllium bearing minerals in beryllium ore is studied by means of optical thin section identification,electron probe analysis and scanning electron microscope.It is found that the beryllium bearing minerals in the ore are zinc garnet with a content of 0.13%~0.35%,and a small amount of Fe and Mn are contained in the zinc solar garnet.The zinc solar eclogite is mainly associated with the low count rate parts,indicating that the zinc solar garnet occurs in the rock fracture.It is speculated that it may be of late metamorphic origin.It is considered that the beryllium orebody in Yangxinyan is formed by the intrusion of granitic magmatic hydrothermal fluid along the contact surface between the Niangniangding granite body and the Huangmailing formation,and is formed by the double metasomatism of magmatic gas and liquid.Niangniangding granite is a Nanhua intrusive rock,which is only host rock.It is possible that the beryllium ore was formed in the late Yanshanian period,which is closely related to the mineralization of beryllium ore body in the Yanshan period.

关 键 词：杨新岩铍矿点 锌日光榴石 岩浆热液型 燕山晚期 

分 类 号：P618.72[天文地球—矿床学]