胶东黄埠岭金矿床红化蚀变与成矿关系探讨

Discussion of the relation between reddenization alteration and mineralization in Huangbuling Gold Deposit,Jiaodong Region

黄埠岭金矿床位于灵北断裂带南西段,主要控矿构造为灵北主断裂上盘次级断裂,直接赋矿围岩主要为黄铁绢英岩。红化蚀变在含矿断裂上、下盘的玲珑型花岗岩中均有发育。岩石化学分析显示,玲珑型花岗岩在红化蚀变中K_2O含量降低,红化蚀变过程中有碳酸盐矿物的聚集,且红化蚀变岩是黄铁绢英岩中铁质的提供者。矿物流体包裹体成分分析显示,包裹体液相成分中富SO_4^(2-),阴离子质量分数SO_4^(2-)>Cl^->F^-。黄埠岭金矿床的形成可以表述为电解成矿机制,红化蚀变岩反映了该体系中阳极附近的水岩反应条件和性质,为金元素的活化区。含金的黄铁绢英岩化蚀变岩反映了该体系中阴极附近的水岩反应条件和性质,为金矿物的聚集区,Au^+的沉淀与电极反应有关。水的电离反应是维系该成矿体系的关键之一。

Huangbuling Gold Deposit is located in the southwestern part of Lingbei fault zone. The ore bodies occur in the subsidiary fractures in the hanging wall of Lingbei main fracture. The direct ore-hosting rock is beresite.Reddenization appears in Linglong granite both of the hanging wall and the foot wall of ore-hosting faults. According to petrochemistry analysis,K_2O content decreases during reddenization of Linglong granite. Carbonate minerals gather in the reddenization rock. And the reddenization rocks is also the provider of iron in beresite. According to the composition analysis of mineral fluid inclusion,SO_4^2-is rich in the liquid phases and the anion mass concentration ranks SO_4^2-Cl^- F^-. The forming of Huangbuling gold deposit can be expressed as an electrolytic metallogenic mechanism. Reddenization reflects the condition and property of water- rock interaction near the positive pole of the system,being the active gold region. Gold-bearing beresitization altered rocks represented the condition and property of water- rock interaction near the negative pole,being the gold-enriching area. The precipitation of Au＋is related to the electrode reaction. The ionization reaction of water is the key to keep the reaction system.