Abstract:

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 μV/℃. The assembledge of the thermoelectric conductive types of the pyrite changes successively from N%﹥P% of the early goldpoor pyrite-sericite-silicification 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 coefficient. 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.

Key words: gold deposit, pyrite, thermoelectric coefficient, thermoelectric conductive type, Yixingzhai, Shanxi