福建紫金山矿田浅成低温热液型矿床成矿物质来源探讨——H、O、S、Pb同位素地球化学证据  

Sources of ore-forming materials of epithermal deposits in Zijinshan orefield in Fujian Province: Evidence from H, O, S and Pb isotopes

作　　者：梁清玲[1] 江思宏[2] 白大明[2] 王少怀[3] 

机构地区：[1]四川省冶金地质勘查局六○六大队,四川成都611730 [2]中国地质科学院矿产资源研究所国土资源部成矿作用与资源评价重点实验室,北京100037 [3]福州大学紫金矿业学院,福建福州350108

出　　处：《矿床地质》2015年第3期533-546,共14页Mineral Deposits

基　　金：国土资源部公益性行业科研专项(编号:200911007-1-17)资助

摘　　要：紫金山高硫型浅成低温热液型铜金矿床和悦洋低硫型浅成低温热液型银多金属矿床为紫金山矿田内2个典型矿床。为了确定矿床成矿流体和成矿金属来源,文章系统研究了2个矿床的H、O、S、Pb同位素组成特征。结果显示,在紫金山铜金矿床深部的铜矿脉中,6件石英的δDV-SMOW值为-62.0‰^-58.5‰,δ18OV-SMOW值为12.0‰~14.6‰,δ18OH2O值介于2.4‰~6.5‰;26件金属硫化物的δ34S值介于-13‰~2.9‰,峰值介于-5‰~1‰;16件金属硫化物的206Pb/204Pb值介于17.966~18.785,207Pb/204Pb值介于15.571~15.722,208Pb/204Pb值介于38.127~38.849。在悦洋矿区的矿脉中,1件石英样品的δDV-SMOW值为66.6‰;5件石英样品δ18OV-SMOW值介于10.0‰~13.7‰,δ18OH2O值介于-1.1‰~3.4‰;13件金属硫化物的δ34S值介于-6.8‰^-1.0‰,平均值-4‰;5件金属硫化物的206Pb/204Pb值介于18.405~18.521,207Pb/204Pb值介于15.620~15.685,208Pb/204Pb值介于38.587~38.863。H、O同位素特征显示,紫金山铜金矿床的成矿流体水主要来自岩浆水,混合少量大气降水;悦洋银矿床则以大气降水为主,有少量的岩浆水加入。硫化物的S和Pb同位素特征显示,紫金山铜金矿床的成矿物质主要来源于早白垩世岩浆岩,悦洋银矿床的成矿物质主要来源于围岩及早白垩世岩浆岩。The Zijinshan high sulfidation epithermal Cu-Au deposit and the Yueyang low sulfidation epithermal silver polymetallic deposit are two typical deposits in the Zijinshan orefield of Fujian Province, which is a famous superlarge polymetallic orefield in China. In this paper, the authors systematically studied H, O, S and Pb isotopic compositions of the two deposits in order to define the source of ore fluids and ore-forming metals. The quartz δDV-SMOW, δ^18OV-SMOW and δ^18OH2O of six samples from the deep copper ore zone in the Zijinshan Cu-Au deposit range from -62.0‰ to -58.5‰, from 12.0‰ to 14.6‰ and from 2.4‰ to 6.5‰, respectively. The δ^34S values of 26 samples of sulfides in the deposit vary from -13‰ to 2.9‰ with the peak values ranging from -5‰ to 1‰. The ^206Pb/^204Pb ratios of 16 samples of copper ore are 17.966-18.785, 207Pb/204Pb ratios are 15.571-15.722, and 208Pb/204Pb ratios are 38.127-38.849, respectively. The δDV-SMOW value of a quartz sample from the Yueyang deposit is 66.6‰, and the δ^18OV-SMOW and δ^18OH2O values of 5 quartz samples are between -10‰ and 13.7‰ and between -1.1‰ and 3.4‰, respectively. The δ^34S values of 13 samples of sulfides vary from -6.8‰ to 1.0‰ with the average value being -4‰. The 206Pb/204Pb ratios of 5 sulfide samples are 18.405-18.521, ^207Pb/^204Pb ratios are 15.620-15.685, and ^208Pb/^204Pb ratios are 38.587-38.863, respectively. The hydrogen and oxygen isotopic compositions indicate that the ore fluid of the Zijinshan Cu-Au deposit was mainly sourced from magmatic water with minor meteoric water, whereas atmospheric water was dominant in the Yueyang deposit, with the mixing of a small amount of magmatic water. Based on the sulfur and lead features, the authors hold that the metals of the Zijinshan deposit were derived from Early Cretaceous magmatic rocks, whereas ore-forming materials of the Yueyang deposit were mainly derived from rocks and Early Cretaceous igneous rocks.

关 键 词：地球化学 成矿物质 紫金山铜金矿床 悦洋银多金属矿床 紫金山矿田 福建 

分 类 号：P618.41[天文地球—矿床学] P618.51[天文地球—地质学]