四川康定偏岩子金矿床成矿流体特征研究
发布时间：2018-08-13 19:47
【摘要】：偏岩子金矿床是康定金矿田的主要矿床之一,康定金矿田为丹巴-康定金矿带重要的组成部分。震旦系上统灯影组中段一亚段第二层中部为矿体的产出层位,块层状的富藻白云岩为赋矿岩石。含金矿脉呈近南北向成带状分布。氟镁石为主要的载金矿物之一,尤其是粒状氟镁石。金属矿物主要有黄铁矿、方铅矿、砷硫锑铅矿、车轮矿、黝铜矿等;非金属矿物主要为石英、氟镁石、白云石、绢云母、萤石、方解石等。矿石的结构主要有结晶结构、交代结构等。矿石构造主要有浸染状构造、脉状构造、晶簇状构造、晶洞状构造、梳状构造等。蚀变类型主要为黄铁矿化、硅化、绢云母化、碳酸盐化、钠长石化、绿泥石化。成矿过程分为金-黄铁矿-石英阶段(I);金-氟镁石阶段(Ⅱ);金-硫化物-氟镁石-石英阶段(Ⅲ);黄铁矿-白云石-石英阶段(Ⅳ),其中Ⅱ、Ⅲ阶段为主成矿阶段。通过对包裹体岩相学特征观察、温度测定、成分分析、热力学计算等,研究成矿流体特征。本矿床流体包裹体类型主要为H_2O溶液包裹体、CO_2包裹体、CO_2-H_2O包裹体,含石盐包裹体,流体包裹体组合显示了流体不混溶的特征。含石盐包裹体仅在第I阶段分布,第Ⅱ、Ⅲ阶段几乎全为CO_2-H_2O包裹体、CO_2包裹体。流体包裹体的均一温度范围为147.0~400℃,盐度范围为0.43~36.4wt%NaCl。从Ⅰ到Ⅳ阶段,包裹体的均一温度、盐度、压力、pH值由高到低的趋势演化,而氧化性有所增强。富CO_2相CO_2-H_2O包裹体的均一温度、完全均一压力范围分别为218.6~342.3℃、98.6~132.6MPa;富H_2O相CO_2-H_2O包裹体的均一温度、完全均一压力范围分别为216.4~315.8℃、107.6~214.7MPa,两种类型CO_2-H_2O包裹体的温压基本一致,说明它们是同时期捕获的CO_2-H_2O不混溶流体包裹体组合。地幔流体沿着郭达山断裂和偏岩子断裂等导矿断裂向上运移,当它进入次级断裂、层间破碎带等容矿构造时,由于压力的骤然降低,致使CO_2在成矿溶液中的溶解度降低,流体发生不混溶作用。流体不混溶作用导致CO_2逸度降低、pH升高,致使金的硫氢络合物溶解度降低在成矿流体中快速沉淀成矿。
[Abstract]:Metamorphic gold deposit is one of the main deposits in Kangding gold ore field, and Kangding gold ore field is an important part of Danba-Kangding gold deposit belt. The middle part of the second layer of the first submember of the Dengying formation of the Upper Upper Series of Sinian is the producing horizon of the orebody, and the algae-rich dolomite of the block layer is the ore-bearing rock. The gold-bearing veins are distributed in the near-north-south direction. Fluorite is one of the main gold-bearing minerals, especially granular magnesium fluoride. Metallic minerals are mainly pyrite galena arsenic antimony lead wheel ore tetrahedrite etc. Non-metallic minerals are mainly quartz fluorite dolomite sericite fluorite calcite and so on. The structure of ore mainly includes crystal structure, metasomatic structure and so on. Ore structure mainly includes disseminated structure, vein structure, cluster structure, crystal cavity structure, comb structure and so on. The alteration types are mainly pyrite silicification sericite carbonization albite and green-mud fossilization. The ore-forming process can be divided into (I); gold-fluoromagnesite stage (鈪，
本文编号：2181997
[Abstract]:Metamorphic gold deposit is one of the main deposits in Kangding gold ore field, and Kangding gold ore field is an important part of Danba-Kangding gold deposit belt. The middle part of the second layer of the first submember of the Dengying formation of the Upper Upper Series of Sinian is the producing horizon of the orebody, and the algae-rich dolomite of the block layer is the ore-bearing rock. The gold-bearing veins are distributed in the near-north-south direction. Fluorite is one of the main gold-bearing minerals, especially granular magnesium fluoride. Metallic minerals are mainly pyrite galena arsenic antimony lead wheel ore tetrahedrite etc. Non-metallic minerals are mainly quartz fluorite dolomite sericite fluorite calcite and so on. The structure of ore mainly includes crystal structure, metasomatic structure and so on. Ore structure mainly includes disseminated structure, vein structure, cluster structure, crystal cavity structure, comb structure and so on. The alteration types are mainly pyrite silicification sericite carbonization albite and green-mud fossilization. The ore-forming process can be divided into (I); gold-fluoromagnesite stage (鈪，
本文编号：2181997
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