广东信宜东坑金矿地质特征及成因浅探

GEOLOGICAL CHARACTERISTICS AND GENESIS OF DONKENG GOLD DEPOSIT IN XINYI,GUANGDONG

东坑金矿地处云开加里东隆起带的东翼，吴川－四会大断裂的西侧，矿床赋存于震旦系云开群中亚群（Ｚｙｎｂ）地层的中下部厚约８０ｍ的绿片岩带中。共圈出４个主矿体，其中最大矿体长１１００ｍ，平均厚度２．０ｍ，平均品位５．５８×１０－６。矿石由石英细脉组成，矿床受区域脆－韧性剪切带控制，矿液来源于银岩花岗岩体的演化分异和对围岩的萃取。矿床形成温度为２６７～３０７℃，属岩浆热液交代－充填型中温热液矿床。

Dongkeng gold deposit is stituated in east limb of Yunkai Caledonian mole track and west side of Wuchuan Sihui major fracture,and located in about 80 m thickness green schist belt which is middle lower part of b formation of Yunkai Sinian system group(Z yn b).Four main ore bodies are obtained,the largest ore body is consist of quartz vein with long of 1 100 m,average thickness of 2 0 m and average grade of 5 58×10 -6 .The deposit is controled by regional brittle ductile shear zone.Ore solution originated from evolution and differentiation of Yinyan granitic body and extracted from country rock.The ore forming tempreture is 267～307℃.The gold deposit is considered to be a magmatic hydrothermal replacement filling mesothermal deposits.