宁夏海原县西华山成矿地质背景及金矿分析

Metallogenic geological background and gold mine analysis of Xihua Mountain in Haiyuan county of Ningxia

西华山地区出露地层为中元古界长城系园河群、西华山群,缺失南华山群.西华山主体为一向斜及一不完整背斜,轴向近东西.断裂构造发育,南、北被深断裂所截,此外尚有北西西向及北东向断裂.西华山金矿主要分布于马场—黑泉一带及柳沟地区,矿区内分布的闪斜煌斑岩脉、石英脉与金矿化关系密切.与小秦岭金矿对比,其金地球化学异常具明显分散矿化特征,成矿流体偏酸性,温度和压力条件相对较高,CO2质量分数偏低,形成矿化较分散,很难形成大的金矿体.

Outcrops strata are Yuanhe group and west Huashan group, belong to Changcheng system of Mesoproterozoic, except south Huashan group. The main block of the west Huashan group is composed of a syncline and an uncompleted anticline with east-west axial direction. Faults are well developed in the area, and the area is cut by faults from south to north. NWW and NE faults also developed. West Huashan gold ore deposit located in Machang-Heiquan and Liugou area. The gold mineralization is closely related to spessartite veins and quartz veins. Contrast with Xiaoqinling gold mine, gold geochemical parameters are anomaly with significantly dispersed mineralization characteristics, the gold ore-forming fluid in this area is acid with higher pressure and temperature conditions and low CO2 mass fraction. The mineralization characteristics are more decentralized and it is hard to form large ore deposit.