陕西凤县八卦庙金矿床地质特征及控矿因素分析

本文通过对八卦庙金矿床成矿地质背景、矿区地质特征、矿体特征、矿石特征和围岩蚀变特征等几个方面的综合研究发现,八卦庙金矿床矿体主要赋存于泥盆系上统星红铺组下段上部岩层铁白云质粉砂质绢云母千枚岩中;成矿作用受北西向一组张扭性断裂构造控制;围岩蚀变特征明显,主要发育有硅化、黄铁矿、磁黄铁矿化、绢云母化、绿泥石化。金矿物赋存状态为自然金,产出状态以粒间金产出为主,其次是裂隙金,包体金较少。构造、蚀变发育地段,金品位相对较高,而结构完整、蚀变程度低的岩石则金品位相对较低。由此笔者认为八卦庙金矿床为由韧性剪切带所控制的蚀变岩型金矿床。

Geological features and ore-controlling factors of Baguamiao gold deposit in Fengxian,Shaanxi Province

In this paper,we comprehensively studied the metallogenic geologic background,the geological features of the mining area and the characteristics of ore body,ore and the alteration of the surrounding rock of the Baguamiao gold deposit. The results show that the ore body of the Baguamiao gold deposit were mainly hosted in iron dolomite silty sericite phyllite of upper part of lower lithologic section of Upper Devonian Xinghongpu Formation. The metallogenesis was controlled by a group of northwestoriented tensile torsional fault structures. The wall rock alteration was obvious,mainly including silicification,pyrite,magnetic pyrite mineralization,sericite,and chlorite. The occurrence of gold ore is natural gold,and the output state was mainly intergranular gold production,followed by fissure gold,and there was a few Inclusion gold. The gold grade is relatively high in the area where the structure and alteration are developed. While the gold grade was lower where the structure of surrounding rock is complete and alteration grade is low. Therefore,the authors believe that the Baguamiao gold deposit is an altered rock type gold deposit controlled by a ductile shear zone.