河北省小石门银金矿床地质特征及成因探讨

Geological Characteristics and Genesis of the Xiaoshimen Silver-gold Deposit,Hebei Province

小石门银金矿位于小寺沟铜钼矿外围,是小寺沟铜钼矿成矿系列的组成部分。矿区内有三条长逾千米的金银矿化带,共17个矿体。矿体赋存于硅质白云岩中,受北北东向断裂及顺层滑脱断层构造控制明显,在空间上和切层或顺层产出的闪长玢岩及二长斑岩关系密切。矿体形态为不规则脉状、透镜状、囊状,矿石成分为富金属硫化物矿石及贫金属硫化物矿石,围岩蚀变主要表现为褐铁矿化、黄铁矿化、硅化、碳酸盐化。从硫同位素特征、稀土元素特征、成矿温度、包体成分特征等矿床地球化学特征综合研究,认为该矿床硫元素和成矿物质来源于与小寺沟杂岩体同源异相岩浆岩,矿床的成矿温度属中低温,矿物组合为中低温矿物组合,成矿热液为岩浆热液。矿床成因为与小寺沟杂岩体及二长斑岩有关的中低温热液充填型矿床。

Xiaoshimen silver-gold deposit is located in outer-ring of Xiaoshigon copper-molydenum deposit and belongs to a part of the Cu-Mo ore-forming system. There are 3-over-1 000 m-long Au-Ag mineralization zones in the area. And they contain 17 ore bodies. The ore bodies are in the siliceous dolomite, controlled by NNE direction fault and bedding decollement fault and have close relationship with phophyritic diorite and monzonite. The ore bodies are non-regular veins, lenses and bursaes. The wall-rock alteration minerals are limonite, pyriteIt, silicate and carbonate. The study on the sulfur isotope, REE, ore-forming temperature and inclusions suggest that the ore deposit is possiblely a mid-lower temperature hydrothermal filling deposit.