闽中丁家山铅锌多金属矿区闪锌矿中Fe、Cd、Mn元素赋存特征及其地质意义

Modes of occurrence of Fe,Cd,Mn in sphalerite from the Dingjiashan lead-zinc ore district in central Fujian Province and their geological significance

闪锌矿内Fe、Cd、Mn等元素含量不但影响闪锌矿的晶胞参数,而且蕴藏着丰富的矿床成因信息。闽中梅仙矿田丁家山铅锌矿区存在磁铁矿型和磁黄铁矿型两类矿石。本文通过X射线原位衍射和电子探针分析分别对两类矿石中闪锌矿的晶胞参数和Zn、Fe、Cd、Mn元素含量进行了测试,结果表明,闪锌矿晶胞参数具有磁黄铁矿型矿石>磁铁矿型矿石>理论值的特征,引起晶胞参数差异的主要原因是闪锌矿内Fe、Mn元素的含量。此外,两类矿石闪锌矿内Fe元素含量差距悬殊,Zn、Fe、Cd元素之间的替代关系和替代强度差异明显,结合研究区地质特征,认为这两类矿石可能是两次不同成矿作用的产物。

The values of Fe,Cd,Mn and other trace elements in sphalerite not only influence its cell parameters but also contain rich information concerning the genesis of the ore.There are two types of ore in the Dingjiashan PbZn ore district of the Meixian orefield in central Fujian Province: the magnetite-type and the pyrrhotite-type.In this paper,the cell parameters and values of Zn,Fe,Cd and Mn of sphalerite in two types of ore were tested by X-ray in situ and electron microprobe analysis.In terms of the cell parameters of sphalerite,the characteristics of pyrrhotite-type > magnetite-type > the theoretical value are mainly caused by different values of Fe and Mn in sphalerite.In addition,the gap of Fe average values in sphalerite in two types of ore is much larger,and the substitutional relation and intensity between Zn,Fe and Cd of sphalerite in two types of ore are completely different.Combined with the geological characteristics of the study area,the authors consider that these two types of ore may be products of two kinds of mineralization.