河南内乡县许窑沟金矿地质特征及成矿过程

Geological Characteristics and Ore-forming Process of Xuyaogou Gold Deposit in Neixiang County,Henan Province

河南许窑沟金矿位于东秦岭造山带朱阳关—夏馆断裂和瓦穴子—乔端断裂共同控制的二郎坪群地层中,矿体主要产于牧虎顶花岗岩岩体与火神庙组接触带中。矿石分为石英脉型和蚀变岩型2类,矿体围岩蚀变发育,蚀变类型较多,主要有硅化、绢云母化、绿泥石化、钾化、碳酸盐化、黄铁矿化、赤铁矿化。含矿石英脉主要包裹体类型包括富气和H2O-NaCl-CO2三相包裹体,成矿期的均一温度主要为310～350℃,盐度一般为2%～7%;成矿晚期均一温度主要为300～340℃,盐度为10%～15%。综合分析认为,许窑沟金矿成矿过程比较复杂,成矿过程中有沸腾作用,同时又存在大气水和岩浆水混合作用,为构造破碎带型的金矿。

Xuyaogou gold deposit is located in Erlangping Group stratum and controlled by ruptures of Zhuyangguan-Xiaguan and Waxuezi-Qiaoduan in east Qinling orogenic belt.The orebody is mainly located in the contact zone of Muhuding granite and Huoshenmiao Formation stratum.Gold ore can be divided into two type including quartz vein and alteration.Wall rock develop many types of alteration,such as silicification,sericitic alteration,chloritic alteration,potassic alteration,carbonatic alteration,pyrite and hematite alteration.The fluid inclusions in ore-bearing quartz vein mainly include gas-rich and H2O-NaCl-CO2;homogenization temperature are from 310 to 350 ℃,and salinity is from 2% to 7% in ore-forming period;homogenization temperature are from 300 to 340 ℃,and salinity is from 10% to 15% in late ore forming period.The ore-forming process of Xuyaogou gold deposit is very complicated,and boiling and mixing of meteoric water and igneous water occures in the ore-forming period.Through comprehensive analysis,Xuyaogou gold deposit is a tectonic fragmentized belt type of gold deposit.