福建紫金山金铜矿黄铁矿成因矿物学特征研究

Study on genetic mineralogical of pyrite from Zijinshan Au-Cu Deposit,Fujian Province

福建紫金山金铜矿矿石中伴生有大量的黄铁矿。通过对黄铁矿的矿相学、晶体化学、热电性、晶胞参数等方面特征的研究,对本矿的成因有了进一步认识。矿相学特征显示,黄铁矿可分为岩浆热液蚀变期、次火山热液矿化期、低温硅化期等三个期次;晶体化学成分具有富硫亏铁特征;三个期次的黄铁矿晶胞参数均大于理想值0.541 76nm,均值为0.541 92nm;黄铁矿导电类型以N型为主,是黄铁矿Fe类置同象程度大于S所致;热电系数显示的成矿温度为120.83～351.24℃。研究结果表明,紫金山金铜矿黄铁矿成因与岩浆热液有密切关系,矿床成因类型为浅成低温热液矿床。

The ores accompany with large amounts of pyrite in Zijinshan Au-Cu Deposit,Fujian Province.We have a further understanding about the genesis of this deposit by investigation of petrography,crystal chemistry,pyroelectricity and cell parameters.According to the characteristics of ore microscopy of pyrite,the pyrite can be divided into three phases：magmatic hydrothermal alteration stage,subvolcanic hydrothermal mineralization stage and the low temperature silicide stage.Crystal chemical composition is characterized by rich in S while poor in Fe.The cell parameters of three pyrite phases are all greater than the ideal value 0.541 76 nm.The pyrite hold conduction type of N,due to the isomorph of Fe is greater than S.The thermoelectricity coefficients show the forming temperature is 120.83～351.24℃.The result shows that the pyrite has a close relationship with magmatic hydrothermal.The genetic type of ore deposit is epithermal deposit.