胶东英格庄金矿床地质地球化学特征

Characteristics of Geology and Geochemistry of the Yinggezhuang Gold Deposit in Eastern Shandong Province

英格庄金矿床是胶东牟平-乳山金矿成矿带重要的石英脉型金矿床之一,其产出和分布严格受NNE向断裂控制,围岩以古老变质岩和昆嵛山花岗岩为主,金矿物主要以晶隙金形式赋存于黄铁矿-脉石晶体之间。通过成矿流体包裹体地球化学研究可知:均一温度变化有3个峰值(155℃～165℃、205℃～215℃和245℃～265℃);该矿床包裹体盐度w(NaCl)较低(<17.17(),在1.05(～17.17(之间变化,应属于低盐度流体;据其成矿压力21.3～58.8MPa,进一步求得的该矿床主要成矿深度为0.83～2.31km,为中浅成矿床;依据包裹体成分测试结果可知,矿床流体属K+-Na+-SO24-Cl-型。氢氧同位素显示其成矿流体主要来源于岩浆水和变质水,并有一定的大气降水混入。

The Yinggezhuang gold deposit is one of the important gold deposits of quartz vein gold type in the Mouping-Rushan gold ore belt of the Jiaodong Peninsula in eastern China.The distribution and occurrence of the gold deposit is controlled by NNE-trending faults.Its wall rock is mainly composed of Archean metamorphic rocks and Kunyushan granite.The gold occurred mainly in beteen minerals（Pyrite and Gangue minerals）.The study on fluid inclusion of quartz from gold ore shows that the homogeneous temperature variation has three peak ranges：155℃～165℃,205℃～215℃,and 245℃～215℃.The inclusion salinity of the deposit is relatively low,ranging 1.05～17.17% NaCl.The mineralization pressure ranges from 210 to 580atm,and the metallogenic depth from 0.83 to 2.31km,implying a meso-epi thermal low salinity deposit.Determination of fluid inclusion gredient shows that ore fluid is of the pattern K＋-Na＋-SO2-4-Cl-.The study result on D-O isotopices shows that the metallogenetic fluid originated from relict magmatic hydrothermal water and metamorphic water mixed with some meteoric water.