大庄子金矿成矿作用地质地球化学特征及成因

胶东平度大庄子金矿床产于胶莱盆地西北缘荆山群变质岩中，主矿体的展布受一低角度层间滑动断层控制，该断层发育于黑云二长片麻岩和斜长角闪岩所夹持的透镜状大理岩中.成矿作用地球化学研究表明：大庄子金矿δ³⁴S组成比胶西北其他金矿高，且高于老地层和中生代花岗岩的δ³⁴S值，反映大气降水循环淋滤作用使硫同位素发生了一定程度的分馏；矿石铅为异常铅，铅同位素组成与同胶东群及玲珑、焦家等中生代花岗岩有关的金矿相比，范围变化大.碳氧同位素组成介于岩浆碳酸岩与荆山群大理岩之间.同位素地球化学研究表明成矿物质具多源性，这与该类金矿所处的构造边缘（转换）环境有关.石英流体包裹体均一温度为280~160℃，包裹体成分和氢氧同位素组成反映成矿流体来自变质水、大气降水和岩浆水的混合.

GEOLOGICAL GEOCHEMICAL FEATURES OF ORE FORMING PROCESS AND ORIGIN OF DAZHUANGZI GOLD DEPOSIT,SHANDONG PROVINCE

Dazhuangzi gold deposit,occurred i n Jingshan group metamorphic rocks o n the margin of Jiaolai basin,is controlled by a low-angle slip fault zone-structural breccia marble zone,whi ch provides structural and physi-cal-chemical conditions for ore-fo rming processes.The isotopic geoch emistry research indicates that the sulfur isotopic compositions of Dazhuangzi gold dep osit are higher than those of other ty pical gold deposits of Jiaodong area.Theδ 34 S values of ore sulfur are generally greater than those of the old strata and granite in Mesozoic Era,reflecting that at-mosphere water circulation results in fractionation of sulfur isotope.The scope of lead isotope of Dazhuangzi gold deposit is wide,suggesting that the lead belong to anomalous lead.The compositions of carbon and oxygen isotopes fall in values between that of magma carbonate and marble.According to the data of sulfu r,lead,carbon and oxygen isotopes a nd fluid inclusions,it was indicated t hat the ore-forming matter is of multiple source.