耿庄金矿床金矿物特征及其矿床成因意义

Characteristics of Gold Mineral in Gengzhuang Gold Deposit and Its Significance to Metallogeny

为深入研究耿庄金矿床成因,开展金矿物特征系统观察研究.用电子探针测定了金矿物成分,计算金的成色.发现金矿物种类主要以银金矿为主,有少量自然金;金矿物成色508～896,平均673.观测金矿物的形状和大小发现,耿庄金矿物以角粒状等不规则形状为主,中粒金、细粒金较多.主要赋存在闪锌矿、黄铁矿、方铅矿等金属硫化物裂隙、晶隙中.结合产出特点和成矿地质条件,分析讨论了耿庄金矿物的形成条件及矿床成因意义.认为耿庄金矿矿床成矿期长,成矿阶段多,经历了中温-中低温成矿阶段,但以低温为主;形成作用为浅成-超浅低温热液成矿.

Based on earlier works,the genesis of gold deposits in Gengzhuang was studied in depth via systematical observations on the characteristics of the gold mineral. An assay was made for the composition of the mineral with an electron probe to determine the fineness of gold. It was found that in the minerals the electrum is the major part with small amount of natural gold and the fineness of gold mineral is 508～896 with an average assay 673. Observations on the shape and the size of the minerals indicated that the gold minerals are mainly in irregular brecciform and most of them are medium-grained or fine-grained,which are found mainly in the cracks and intracrystallines of sphalerite,pyrite,galena and other metallic sulphides. Combining the occurrence characteristics with ore-forming geological conditions,the forming conditions and ore genesis of Gengzhuang gold deposit are discussed,and it is revealed that the gold deposit experienced long-term metallogenic epoch and many genetic stages,i.e.,the mesothermal-hypothermal ore-forming stages of which the hypothermal stage was dominant. The deposit is of hypabyssal or ultra-hypabyssal epithermal genesis.