论滇中砂岩铜矿浅、紫交互带赋矿及其金属硫化物分带之成因与成矿作用演化

A Discussion on the Genesis of Sandstone-hosted Copper Deposits Occuring in the Contact Zone between Purple and Gray Sandstone,Metallic Sulphide Zoning and the Evolution of Metallization in Central Yunnan

康滇古大陆裂谷的发生和演化造就了楚雄盆地,沉积出煤、铜、盐旋回与含矿建造和矿床组合。铜矿的生成(特别是改造富集)与煤(有机质)、盐(热卤水)密切相关。大姚—牟定式砂岩铜矿以其规模最大而具代表性。它的成矿作用的演化是从风化沉积作用到成岩作用、后生作用再到改造作用。作用的结果是分别产生含铜有机质沉积体、成岩矿层、后生矿层和改造富矿体。层状矿体赋存于砂岩浅紫交互带是氧化性流体与还原性流体相汇于斯而发生氧化—还原反应沉积成岩的结果。其金属硫化物的生成顺序与分带是遵循S、O、Fe、Cu热液体系中矿物共生组合规律的,随介质条件、四元素浓度的差异而变化。

The occurrence and evolution of paleo-continental rift in the Kangdian region brought up a Chuxiong basin, deposited cycles of ore-bearing formations of coal, copper and evaporate, and formed the associated coal, copper and saline deposits. The ore forming especially being rich in reworked period is closely related to salt （brine） and coal （organic material）. Dayao-Muding type sandstone-hosted copper deposits are the largest one and have the best representative characteristics in central Yunnan. Their evolution of metallization is from weathering- sedimentogenesis to diagenesis, anadiagenesis and reworking. The products of these metallization respectively are copper-organic sediments, diagenetic copper beds, anagenetic copper beds and reworked ore shoots. The stratiform ore-body occurred in the contact zone between purple sandstone and gray one, and is mineralized product by oxidation-reduction caused by join of oxidated fluid and reducing one. The generation sequence and zoning of the metallic sulphides accord with law of mineral association of O, S, Fe, Cu ions in thermal water system, and vary with medium condition and density of above four elements.