摘要
凡河元古宙拗拉谷属地幔活化型中的克拉通拗拉谷。从长石石英砂岩—碳酸盐岩—细碧岩组合到石英砂岩—碳酸盐岩—页岩组合序列,表明它是一个夭折的裂谷。关门山铅锌矿床矿物组成简单,多次沉淀,有溶蚀、交代及分带现象。矿石包裹体成分及氢氧同位素组成表明成矿流体属大气降水混合的Na—Ca—Cl型盆地地层水,成矿温度为150—300℃。铅同位素表明成矿物质来自上地幔或下地壳,大约在1900Ma从源区分离出来进入太古宙结晶基底。硫同位素表明硫源相当海水硫酸盐,保存在成岩时由晶间水、孔隙水、软泥水集中起来的层间水里。矿床特征及稳定同位素表明成矿组分的迁移有早期的动静结合的混合模式与晚期的还原硫模式二种,沉淀也有早期的贱金属流体与H,S流体混合机制与晚期的pH值改变、温度降低,溶液稀释机制二种。成矿与基底隆起、基底断裂、盖层断裂、层位、岩性、古水文条件等有着密切的关系。矿床类型属密西西比河谷型后生矿床。
The Proterozoic aulacogen at Fanhe area, belonging to mantle activation-type craton aulacogen, came to premature end shown by the sequence from feldspathic quartz sandstone-carbonatite-spilite to quartz sandstone-carbonatite-shale.In Guanmenshan Pb-Zn deposits, mineral composition is simple, deposition has happened many times and there are resorption, replacement and zoning appearance. The inclusion composition and the isotope of hydrogen and oxygen show that ore-forming fluid is Na-Ca-Cl basin strata water of atmospheric precipitation' and mineralization temperature is 150-300℃. Pb isotopic data indicate that ore-forming material came from upper mantle or lower crust and went into Archaeozoic crystalline basement 1900Ma ago. S isotopic evidence suggests that sulphur originated from marine sulfate and stored in the interlayer water, consisted of intercrystalline water, void water and muckle water. The characteristics of the deposit and stable isotope show that the migrating models of ore-forming composition are early mixed One in active and static state and late reducing sulphur cne; the precipitating mechenisms are early mixed one of base metal fluid and HaS fluid,and late one of various pH value, lower temperature and dilute liquid. The forming of thc deposit has close relationship with basement upwarping, basement faulting, overlying strata faulting and the other factors such as position, lithological characters and palaeo-hydrologic conditions. The Pb-Zn deposits are Of Mississippi valley-type ore deposits.
出处
《辽宁地质》
1991年第3期193-218,共26页
关键词
铅锌矿
矿床
成因
元古庙
凡河
Fanhe Proterozbic Guanmenshan Pb—Zn deposit Mississippi valley—type
