摘要
云南老王寨金矿床的玄武岩、矿化玄武岩、煌斑岩、矿化煌斑岩的 Au、Ni、Cu等微量元素不同步富集 ,表明金不是在玄武岩和煌斑岩岩浆和热液作用过程中富集的。矿化围岩的金相对富集程度高 ,铜、铅、锌、银的相对富集程度低。矿化玄武岩的 δ1 8O值为 10 .5‰ ,玄武岩的 δ1 8O值为 8.7‰ ;含少量黄铁矿的矿化煌斑岩的 δ1 8O值为 14.7‰ ,弱蚀变煌斑岩的 δ1 8O值为 11.2 % ,最强烈矿化煌斑岩 δ1 8O值为 11.1‰ ;表明矿化流体不是大气降水成因的流体 ,成矿作用后期 ,大气降水成因的流体加入矿化热液体系。热液方解石锶同位素初始值 (87Sr/ 86 Sr) i,为 0 .712 12 3± 30 ,Nd同位素组成的现今比值相对于CHUR地幔源中 Nd同位素组成现今比值的万分偏差 εNd(0 )为 1.14,相对于方解石形成时 CHUR地幔源分馏沉淀程度的参数 f Sm Nd为 0 .13,与海洋环境下形成的玄武岩一致。
The trace elements as Au,Ni and Cu of basalt,mineralization basalt,lamprophyry,mineralization are not simultaneouly rich in the Laowangzhai mine.Therefore it is indicated that the gold mineralization did not take place in the basaltic and lamprophyric magmatism and magmatic fluid process.The relative gold content in the mineralization wallrocks is high,and the Cu,Pb,Zn and Au are low.The δ18O of the mineralisation basalt,basalt,serious mineralization lamprophyry,thin mineralisation lamprophyry and serious mineralization lamprophyry are 10.5‰,8.7‰,11.1‰,14.7‰ and 11.2‰ separately.It is shown that mineralization fluid was not of meteroic origin,but added by fliud of meteroic origin at late mineralization stage.The(87Sr/86Sr)_i,ε_Nd(0) and f_Sm/Nd of the hydrothermal calcite are 0.721123±30,1.14 and 0.13 respectively,which are unanimous with the crust rocks formed in the ocean.
出处
《黄金科学技术》
2000年第2期15-20,共6页
Gold Science and Technology
基金
中国科学院"八五"重大资助项目! ( KZ85 -12 )
关键词
微量元素
同位素
成矿物质
金矿床
Microelement
Isotope
Ore-forming matter
Gold ore deposit
Laowangzhai
