老挝沙耶武里巴莱孔沙湾金矿床研究

孔沙湾金矿床位于老挝中辽地区的西部巴莱县,矿床金平均品位达3.65×10-6。在下二叠统的剪切构造带中发现厚度大于300 m的透镜状、细脉状金矿(化)体,判断该地层为矿区主要含矿层位。金矿体的产出受NNE向为主的宽缓复式褶皱、断裂和纵向、NNW向的断裂、次级褶皱以及横向次级断裂控制,同时矿区大量节理裂隙、面理构造以及众多小型次级断裂构造发育。矿区单元素异常总体呈NE向,与矿区大断裂构造方向一致;硅质岩及角岩中的Au元素异常平均值较高,达0.021×10~(-6)及0.022×10~(-6);二叠系玄武岩和硅质岩中Au元素异常值最高,达0.69×10~(-6),具备良好的成矿远景。推断孔沙湾金矿床类型属于为受构造和次级构造破碎带控制的热液蚀变岩型金矿床。

Investigation of Kongshawan Gold Deposit in Balai County,Phongsaly Province,Laos

Kongshawan Gold Deposit is located in Balai County in the west of Central region in Laos whose aver-age gold grade is 3 .65 ×10 -6 .The gold ore bodies that are lenticular and veinlet occur in shear structure zone of Low-er Permian,and the thickness is greater than 300 m.So this stratum is judged as the main ore-hosting stratum.The out-put of gold ore bodies is mainly controlled by rolling duplex NNE-trending fold and fault fracture,together with vertical and NNW-trending fault,subsidiary fold and horizontal subsidiary fault.At the same time,there are lots of joint fis-sures,foliation and a number of little subsidiary fractures in the ore district.Single element anomalies are generally in NE-trending distribution in ore district,the same with the trending of the major fault fracture.The higher average value of Au element anomalies happens in silica rock which is 0.021 ×10 -6 and hornstone which is 0.022 ×10 -6 .The highest value is 0.69 ×10 -6 which is distributed in silica rock and basalt of Permian.It shows that the ore district has good metallogenic prospects.It is concluded that Kongshanwa Gold Deposit is a hydrothermal altered rock type gold deposit controlled by tectonic and subsidiary tectonic fractured zone.