紫金山铜金矿黄铁矿热电性特征及其地质意义

Thermoelectric Characteristics of Pyrite in the Zijinshan Copper-Gold Deposit and Its Geological Significance

紫金山铜金矿床是高硫化型浅成热液矿床.本文系统地研究了该矿床黄铁矿的热电性特征,探讨了其与成矿温度、成矿阶段、矿体规模等方面的关系,并应用矿物学填图法对该区的深部找矿远景进行了预测.研究结果表明,该矿床的形成温度集中在80～100℃、240～350℃,属中低温矿床;黄铁矿热电性的热电导型以N型为主,总含量达86.15％,热电系数均值为-168.07 μV/℃,在时间和空间上,黄铁矿的热电系数（高负值-低负值-高负值）和N型出现率（高-低-高）都具有韵律变化,从成矿前期到成矿期,黄铁矿P型导电类型的出现率增大,且出现N-P混合型;黄铁矿热电系数分散程度较大,黄铁矿的成矿环境不稳定;矿体的相对埋深表明矿体的变化梯度较大,其产出不稳定,从NW轴向上看,矿体的平均剥蚀百分比数值和相对埋深的绝对值呈现韵律变化,由高到低再到高,由此可以推测,在2号与4号勘探线之间-230 m以下可能有富矿体的存在.

Zijinshan copper-gold deposit belongs to high sulfide epithermal type deposits.This paper systematically discussed the ore-forming temperatures,mineralization stages and orebody size of the Zijinshan copper-gold deposit by studying thermoelectricity characteristic of pyrite from the deposit,and evaluated the prospects at depths in the ore district by using mineralogical mapping.The study shows that the deposit is a low-medium temperature copper gold deposit,with formation temperature concentrated in 80～100℃ and240～350℃.The thermoelectric conductive type of pyrite is dominative of Ntype,and the N type pyrite grains （N％） reaches 86.15％ of the total content,with a mean thermoelectric coefficient of the N type pyrite being-168.07 μV/℃.In terms of time and space,the thermoelectric coefficient （high negative-low negative-high negative） and the percent of the N type pyrite grains （high-low-high） show the rhythmic feature.From the early stage of the metallogenic to metallogenic period,the occurrence rate of p-type conductive type increased,coupled with presence of N-P mixed type.The dispersion degree of pyrite thermoelectric coefficient in this area is high,indicating an unstable environment of pyrite.The relative depth of the ore body indicates that the change gradient of the ore body is high,with an unstable occurrence.From the NW axial view,the average percentage of erosion and the absolute value of the relative depth of the orebody present a rhythm change from high to low and the back to high.It can be speculated the existence of bonanza under-230 m between section line 2 and section line 4.