辽宁小塔子沟金矿床矿脉地球化学特征及找矿标志

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

在小塔子沟金矿,Ba、As、Sb、Hg、Pb为前缘元素,Mo、Co、Ni为尾晕元素,Bi、Ag、Cu、Zn为主要伴生元素。随着矿脉深度的加深,Na2O逐渐变大,TFeO逐渐变小,利用根据这种关系拟合成的线性方程可预测矿脉的深度。在有规模的矿脉中,石英流体包裹体的均一温度变化区间比较宽(160-400℃),流体的盐度变化范围大(0-9%);而在规模较小的矿脉中,温度比较高(280-400℃),盐度比较低(<5%)。在矿脉的深部,成矿流体的温度比较高,盐度比较低,包裹体数量明显减少。根据上述找矿标志,1号脉19中段以下的深部出现有规模工业矿体的可能性不太大;2号脉的成矿前景可能好于5、6号脉;距北大山二长花岗岩南1-3 km范围是寻找新的平行富矿体的最有利地段。

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 Na2O 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.