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四川会东小街金矿床为川西产于元古宙绿片岩地层中的菱铁矿型金矿床的典型代表。金矿体呈脉状产于中元古界会理群青龙山组碳质板岩、流纹质凝灰岩、变粗面岩和花岗斑岩的内外接触带中 ,受 EW向基底断裂的次级断裂和层间破碎带的严格控制。矿石矿物组合为黄铁矿、毒砂、黄铜矿、黝铜矿族、 Au- Ag系列矿物、石英和菱铁矿。其成矿元素组合为 Au- Cu- Ag- Pb- Sb- As- Fe。围岩蚀变以硅化、粘土化和碳酸盐化 (菱铁矿化、方解石化 )为主。由稀土元素、同位素和流体包裹体特征可以推定 ,矿石中矿质主要来自青龙山组板岩、千枚岩等 ,流体可能主要属岩浆热液。含金硫化物石英脉体可能主要形成于澄江期。矿床是在浅成条件下由低密度、中等盐度的弱碱性 -碱性流体在还原环境中生成的火山喷流沉积 -区域变质预富集 -岩浆热液改造型矿床。
The gold deposit of Huidong Small Street in Sichuan Province is a typical representative of Siderite greenstone gold deposits in western Sichuan. The gold ore bodies are vein-shaped in the inner and outer contact zones of carbonaceous slate, rhyolitic tuff, varicosity rock and granite porphyry in the Qinglongshan Formation of the Paleoproterozoic Huili Group, Strict control of the fracture and the layer of broken belt. The ore minerals are pyrite, arsenopyrite, chalcopyrite, tetrahedrite, Au-Ag series minerals, quartz and siderite. The metallogenic element combination is Au-Cu-Ag-Pb-Sb-As-Fe. Wall rock alteration to silicification, clay and carbonation (siderite mineralization, calcite) based. Based on the characteristics of rare earth elements, isotopes and fluid inclusions, it is presumed that the minerals in the ore mainly come from the slate and phyllite of Qinglongshan Formation, and the fluids may be mainly magmatic hydrothermal fluids. Gold-bearing sulfide veins may form mainly in Chengjiang period. The deposit is a volcanic jet deposition-regional metamorphic preconcentration-magmatic hydrothermal mineralization deposit formed under the shallow conditions from low-density, moderate-salinity weak alkaline-alkaline fluids in a reducing environment.