GEOCHEMICAL CHARACTERISTICS OF GOLD LODES AND ORE-PROSPECTING CRITERIA IN THE XIAOTAZIGOU GOLD DEPOSIT,LIAONING PROVINCE

In the Xiaotazigou gold deposit,Ba,As,Sb, Hg and Pb belong to the frontal halo elements,Mo,Co and Ni to the rear halo elements,and Bi,Ag,Cu and Zn to the main elements.The content of Na_2O in the lode increases with depth while the content of TFeO decreases.The linear equation formulated on the basis of fitting of such relationships can be used to predict the lode depth.In some large and high grade lodes,the temperature of the quartz fluid inclusions changes greatly(160～400 ℃),and so does the salinity of fluids(0～9%).In some relatively small lodes,the ore-forming temperature is higher(280～400 ℃) and the salinity is lower(5%).In the deep part of the ore body,the quantities of the inclusions decrease obviously,the mineralizing temperature gets higher and the salinity of the fluids gets lower.Based on the prospecting criteria,it seems that no more industrial ore bodies are likely to be found below the level 19 in No.1 lode,and that No.2 lode probably has more potential than No.5 and No.6 lodes.The area 1～3 km south of the Beidashan monzonitic granite is the most favorable place in search for new,parallel and high-grade ore bodies.