山西义兴寨金矿床地球化学研究

GEOCHEMISTRY FEATURES OF YIXINGZHAI GOLD DEPOSIT IN SHANXI PROVINCE

晋东北地区以唐河大断裂为核心的一组早燕山期 NW向张剪性断裂与区域 NE向复向斜复合部位 ,控制着区内燕山期中酸性浅成侵入体及其与之有关的铁、金、铜矿化 ,义兴寨金矿是该地区具代表性的典型矿床。金矿床为热液型脉状金 -多金属矿床 ,矿体受岩体和断裂构造控制。金矿床分 4个成矿期 ,8个亚期。对金矿床的矿床地质特征、成矿流体成分、性质、成矿物理化学条件及成矿时代的研究表明 ,成矿溶液的 p H值为 6 .1 6～ 6 .5 3:Eh值为 -0 .2 81～-0 .2 80 ;lgf O2 =-3.6～ -2 9,lgf CO2 =4 .3～ 5 .2 ;成矿温度为 1 90～ 349℃ ;成矿压力为 2 0 .0～ 76 .0 MPa;矿床主成矿期石英的 40 Ar— 3 9Ar坪年龄为 ( 1 31 .4± 3.1 ) Ma。

Yixingzhai gold deposit located in the middle- south of Hengshan mountains in Shanxi Province is controlled both by tectonics and by Yanshanian magma activation.The gold depositis the vein deposit.The authors discuss the geological characteristics of gold deposit,geochemical features of ore- forming solution, physico- chemicalconditionsof metallogenesis and ore- forming chron.The study revealsthe temperature range from1 90℃ to34 9℃ ,the mineralization pressure range from2 0 .0 MPa to76.0 MPa.The valuesofp H from 6.1 6to 6.5 3;Eh from- 0 .2 81 to - 0 .2 80 ;lgf O2 from- 36to- 2 9and lgf CO2 from 4 .3to 5 .2 . The main ore- forming chron is( 1 31 .4± 3.1 ) Ma。