摘要
对阳山金矿床进行的地质学、地球化学研究表明 ,矿石中金主要以微细粒金 (2～ 3μm)包裹于毒砂、黄铁矿等矿物之中 ;矿石中As、Sb及有机碳含量较高 ,且Au与Ag、As、Hg、Sb等低温热液元素相关性明显。流体包裹体均一温度为 15 0～ 2 5 0℃、盐度w(NaCleq)为 1.6 %～ 6 .5 % ,流体包裹体成分以H2 O和CO2 为主 ,含少量CO、CH4 、H2 。黄铁矿、辉锑矿δ34 S值为 - 3.47‰～ +13.2 3‰ ;石英δ18O值为 - 3.0 9‰～ +0 .41‰ ,δD值为 - 92 .4‰～- 6 2 .9‰ ;全岩δ13C值为 - 2 .19‰～ - 9.14‰ ,δ18O值为 - 13.5 4‰～ - 9.0 6‰。反映了成矿流体为低温、低盐度热液 ,其组成以大气降水为主 ,并有岩浆热液参与 ,成矿物质来自泥盆系地层及燕山期岩浆岩体 ,矿床为受构造直接控制的、与沉积作用及燕山早期岩浆活动有成因联系的叠加改造型微细浸染型金矿床。
The Yangshan gold deposit, located in south Gansu Province, is a superlarge fine-grained disseminated gold deposit discovered in 1997. Four known ore blocks of the deposit all occur in Devonian epimetamorphosed sandstone, phyllite or limestone. The ore belt is controlled by Anchanghe-Guanyinba fault and its secondary faults. The orebodies, in lenticular or veinlike forms, are spatially and temporally related to plagiogranite. Pyrite and arsenopyrite are the main metallic minerals which usually contain micrograined native gold (2～3 μm. As, Sb and C contents of the ore are high, and Au shows positive correlation with epithermal ore elements such as Ag, As, Hg and Sb. Fluid inclusion study shows that the temperature of the ore fluid ranges mainly from 150℃ to 250℃, and the salinity mainly 1.6% NaCl to 5% NaCl. Gas components of the fluid are mainly H 2O and subordinately CO 2 with trace amounts of such components as CO, CH 4 and H 2. Isotope analysis shows that the scattered δ 34S values of pyrite and stibnite range from -3.47‰ to +13.23‰, δ 18O values of quartz from -3.09‰ to +0.41‰, δD values of quartz from -92.4‰ to +0.41‰, δ 13C values of the bulk rock from -2.19‰ to -9.14‰, and δ 18O values of the bulk rock from -13.54‰ to -9.06‰. These data indicate that the ore fluid is mainly meteoric water together with minor magmatic water, and that Devonian epimetamorphosed sediments and early Yanshanian plagiogranite are the ore source. Therefore, the Yangshan gold deposit is a superimposed fine-grained disseminated gold deposit directly controlled by faults and genetically related to Devonian sediments and early Yanshanian magmatic activities.
出处
《矿床地质》
CAS
CSCD
北大核心
2003年第1期24-31,共8页
Mineral Deposits
基金
武警黄金指挥部专项基金 (编号 :HJ0 0 0 1)资助
关键词
甘肃
地球化学
金矿床
地质特征
成矿物质
岩浆活动
geochemistry,micro-dissemination type, gold deposit, geological features, Yangshan
