作　　者： ; ;

机构地区： 南京大学地球科学与工程学院地球环境计算工程研究所

出　　处： 《矿床地质》 1996年第4期358-364,共7页

摘　　要： 乳山金矿床是胶东近年来探明的一个赋存在花岗岩中的石英脉型金矿床。矿区出露的煌斑岩金含量较低，不可能是金矿化的重要物源者；成矿流体的成分与大气降水热液成分相类似，其氢、氧同位素值也很好地反映了大气降水经不同温度和Ｗ／Ｒ比值条件下水岩交换后的分布特征；锶同位素研究则表明，成矿物质主要来自昆嵛山花岗岩体。 The Rushan gold deposit, one of the quartz vein type deposits, is located in biotite monzonitic granite of Kunyushan complx pluton in Jiaodong region of China. Analyses show that gold content of lamprophyres from the gold deposit is not higher than that of common igneous rocks, the average gold abundances of all types of lamprophyres do not show obvious differences and vary around 2.5×10 -9 , suggesting that in Jiaodong region it was quite impossible for lamprophyres to provide gold mineralization with material . The main metallogenic stage of the Rushan gold deposit has a temperature of 220～280℃, and the wt.% NaCl equiv. values of ore forming fluids are between 5% and 9%, the gaseous phase in the fluid inclusions are dominated by H 2O and CO 2, and the liquid phase are rich in Na +,Ca 2+ ,Cl -, poor in K +,F -, and characterized by Ca 2+ >Na +>K + (three samples) or Na +>Ca 2+ >K + (six samples), quite similar to the composition of the ore forming fluid derived from meteoric water. Initial data on the hydrogen and oxygen isotopic compositions of ore forming fluid fall within a wide range: δD H 2O =-128‰～-71‰ per mil and δ 18 Ο H 2O =7.7‰～6.0‰ per mil,relative to SMOW; nevertheless, meteoric water alone can evolve into the observed isotopic compositions of the gold deposit through isotopic exchange reaction with granitic rocks at temperature between 200℃ and 350℃. The Rb Sr isochron age of the Rushan gold deposit and its country rock Kunyushan biotite granite is (104.8±1.5)×10 6a and 134.3×10 6a,respectively,with ( 87 Sr/ 86 Sr)being 0.71307 and 0.7096 respectively. The time interval between the crystallization of the granite and the formation of the deposit is very long (≥30×10 6 a), but the ( 87 Sr/ 86 Sr) i ratio of the gold mineralization is close to that of the granite. A genetic model in which the meteoric water react with granitic rocks at different temperatures and W/R ratios can be used to explain the metallo

关 键 词： 煌斑岩 氢 液包体 氢 锶 金矿床

领　　域： [天文地球] [天文地球] [天文地球] [天文地球]