胶东西北部望儿山金矿床黄铁矿标型特征及找矿意义

Typomorphic characteristics of pyrite in the Wang’ershan gold deposit,northwest Jiaodong,and its prospecting significance

对胶东西北部望儿山金矿床中的黄铁矿进行了系统的采样和热电系数、热电导型、晶胞参数、化学成分等特征的分析,在此基础上探讨了黄铁矿的找矿意义。研究表明,望儿山金矿床中的黄铁矿化学成分亏S,特征元素为Au、Ag、Cu、Pb、Zn、As、Co、Ni、Se;黄铁矿热电导型P型的出现率为29.4%,热电性各项参数的变化在时间和空间上都与矿石金品位有明显的相关性;黄铁矿热电系数-温度标尺显示成矿温度集中在130.3~339.8℃之间;黄铁矿晶胞参数a0、v0值及X射线衍射峰半高宽都偏低,具有深部黄铁矿特征。黄铁矿δFe-δS图和晶胞参数a0图均显示望儿山金矿床为中低温热液成因,矿体的剥蚀程度较深,向下可能转化为蚀变岩型。

The Wang’ershan gold deposit is located in southern Wang’ershan fault belonging to the Jiaojia gold orefield and lies in the western part of Zhaoyuan-Laizhou gold ore belt of Shandong Province.As a large-scale gold deposit,it combines the characteristics of both altered rock type and quartz vein type.Systematic sampling was conducted.The typomorphic characteristics of pyrite and its prospecting significance were discussed.The chemical composition of pyrite is characterized by sulfur depletion and relative enrichment of Au,Ag,Cu,Pb,Zn,As,Co,Ni and Se as trace elements.The occurrence ratio of P-type pyrite is 29.4%in the Wang’ershan deposit.The parameters of thermoelectricity and thermal resistance of pyrites are closely related to gold grade in time and space.The metallogenic temperatures are concentrated in 130.3~339.8℃according to the thermoelectric coefficienttemperature scale.Cell parameters(a0 and v0)and half-peak bandwidth of X-ray diffraction in pyrites are low,with the feature of deep-derived source.δFe-δS plots and lattice parameter a0 show that the Wang’ershan gold deposit might be a mid-low temperature hydrothermal deposit with relatively serious denudation.It may grade into altered rock type in the deep part.