山西繁峙义兴寨金矿黄铁矿热电系数与导型特征及其地质意义

Thermoelectric Coefficient,Conductive Type and Significance of the Pyrite from Yixingzhai Gold Deposit in Fanshi County,Shanxi Province,China

山西省繁峙县义兴寨金矿为一大型石英脉型矿床。为了获得含金石英脉空间分带性和相对埋深的信息,利用BHTE-6型热电仪,对35件矿石样品4 158粒黄铁矿进行了热电系数分析。结果表明,该矿床黄铁矿的热电导型以N型为主,N型黄铁矿出现率为75.1%,热电系数均值αN为-155.3μV/℃。时间上从早到晚,从黄铁绢英岩化阶段到石英碳酸盐阶段,黄铁矿热电导型组合从N%(P%渐变为N%(P%;空间上从上到下,从1 190 m中段到830 m中段,N型黄铁矿热电系数均值的绝对值|αN|和N%增大,P型热电系数均值αP和P%减小,具正向分带的变化规律。通过上述参数获得矿床的形成温度为143.3~323.3℃,为一中低温热液矿床。热电系数在0^-200μV/℃之间的黄铁矿是富金矿段的标志。按照经验公式计算结果,现开采中段属矿体的中下部位置,但相对埋深部位稳定。综合分析认为,该矿床830 m以下仍有良好的找矿潜力。

The gold deposit in Yixingzhai area, Fanshi County of Shanxi Province, is a large scaled quartz vein type deposit. In order to obtain more information about the zoning of the gold veins, totally 4,158 pyrite grains from 35 ore samples were analysed using a BHTE -6 type of thermoelectric instrument. The result reveals that the thermoelectric conductive type of the pyrite is mainly of N type, and the percent of the N type pyrite grains （ N% ） amounts to 75.1% of the total, with a mean thermoelectric coefficient of the N type pyrite （^-αN） being -155.3 μN/℃. The assembledge of the thermoelectric conductive types of the pyrite changes successively from N% 〉 P% of the early gold-poor pyrite-sericite-silicifieation stage to N% 〈 P% of the later silicate-carbonatification stage. Spatially, the absolute mean value of ^-αN （ ｜ ^-αN ｜ ） and N% increase downward from the 1,190 m level to the 830 m level with decreasing of the value of ^-αP and P%, indicating a normal vertical zoning sequence. A low-medium temperature of 143.3 - 323.3 ℃ is derived by calculation of pyrite thermoelectric co- efficient. The thermoelectric coefficient of the pyrite in the rich ore segment is confined within the range of 0 - -200 μV/℃. A calculation with empirical formula implies that the lower to middle parts of the orebody have been exhumed until now, whereas the buried ore is spatially quite stable. Furthermore, the authors suggest that good exploring prospect would be expectable below 830 m level.