山东招远大尹格庄金矿成矿流体特征  

Characteristics of ore-forming fluids of the Dayingezhuang gold deposit in Eastern Shandong, China.

作　　者：沈昆 胡受奚[2] 孙景贵[2] 凌洪飞[2] 赵懿英[2] 孙明志[2] 

机构地区：[1]山东省地质科学实验研究院,济南250013 [2]南京大学地球科学系,南京210093

出　　处：《岩石学报》2000年第4期542-550,共9页Acta Petrologica Sinica

基　　金：国家自然科学基金项目 (4973 3 12 0 );南京大学成矿作用国家重点实验室开放基金联合资助

摘　　要：大尹格庄金矿位于中国胶北地体西北部招平断裂带下盘的蚀变花岗质碎裂岩 (绢英岩 )带中 ,断裂上盘为胶东群变质岩系。金主要产于黄铁绢英岩和黄铁矿±多金属硫化物 +石英±碳酸盐脉 -细网脉中 ,构成细脉 -浸染状矿石。对蚀变围岩和金矿石中流体包裹体的研究表明钾长石化岩 (钾长石 -石英脉 )和绢英岩 (第 I和第 II阶段 )的石英中含有丰富的 CO2 -H2 O包裹体 ,而金 -硫化物矿石和石英 -碳酸盐脉 (第 III和第 IV阶段 )中 CO2 - H2 O包裹体数量逐渐减少。显微测温指示 ,钾长石化岩和绢英岩石英中的 CO2 - H2 O包裹体的均一温度范围为 2 80～ 36 0℃ ;而金 -黄铜矿和金 -方铅矿 -闪锌矿矿石中包裹体的均一温度分别为 2 40～ 2 75℃和 180～ 2 5 0℃。显微测温和激光拉曼探针分析表明 ,第 I和第 II阶段的成矿流体含 10～ 2 5mol% CO2 ;而第 III和第 IV阶段的含 <5～ 10 mol% CO2 ,并含少量至可观数量 CH4,H2 S和 SO2 等。广泛的黄铁矿化、碳酸盐化蚀变以及缺乏较高盐度的水包裹体说明金很可能是以硫络合物和碳络合物形式被搬运。金的沉淀与温度下降、由裂隙的(重复 )开放引起明显的压力降低和原始流体的不混溶作用有关 。The Dayingezhuang gold deposit lies in the footwall altered granitic cataclasites, i.e. sericite quartz rocks of the Zhaoyuan Pingdu fault in the northwest of the Jiaobei terrain, eastern Shandong, China. Gold occurs mainly in pyrite sericite quartz rocks (PSQ) and pyrite±polymetallic sulphides+quartz ±carbonate veins and stockworks, forming veinlet disseminated ores. Fluid inclusion study on the altered wall rocks and gold ores indicates that quartz in K spar quartz rocks (KFQ) and PSQ (stages I and II) contains abundant CO 2-H 2O inclusions, whereas in gold sulphide ores and quartz carbonate veins (stages III and IV) CO 2-H 2O inclusion abundance decreases gradually. Microthermometry shows that homogenization temperatures of the primary CO 2-H 2O inclusions in KFQ and PSQ fall in the range of 280~360℃; those for Au chalcopyrite and Au galena sphalerite ores fall mainly in the range of 275~240℃ and of 250~180℃, respectively. Also microthermometry and Raman microprobe analysis suggest that hydrothermal fluids contain 10~25mol% CO 2 for stages I and II, and < 5~10 mol% CO 2 for stages III and IV in general, with minor CH 4, H 2S and SO 2 as well. Extensive pyrite and carbonate alterations and the lack of saline aqueous inclusions imply that gold was transported most likely as sulphide complex and, to a less extent, as carbonate complex. Gold precipitation was caused by cooling and unmixing of the parent CO 2-H 2O fluids in response to the (repeated) opening of fractures and consequent pressure drop.

关 键 词：流体包裹体 显微测温 成矿流体 金矿床 地质 

分 类 号：P618.51[天文地球—矿床学]