楚雄盆地砂岩型铜矿床构造-流体耦合成矿模型  

Coupling Tectonic-Fluid Metallogenic Model of the Sandstone-Type Copper Deposit in the Chuxiong Basin,China

作　　者：韩润生[1,2] 邹海俊[1,2] 吴鹏[1,2] 方维萱[3] 胡煜昭[1,2] 

机构地区：[1]昆明理工大学国土资源工程学院 [2]有色金属矿产地质调查中心西南地质调查所,昆明650093 [3]有色金属矿产地质调查中心,北京100012

出　　处：《地质学报》2010年第10期1438-1447,共10页Acta Geologica Sinica

基　　金：国家危机矿山接替资源勘查项目(编号200453001);国土资源部危机矿山专项(编号20089943);昆明理工大学创新团队项目(2009)资助成果

摘　　要：砂岩型铜矿床是楚雄陆相红层盆地的典型矿床类型。在构造-流体-成矿体系的动力学演化中,该类矿床的形成经历了沉积-成岩成矿作用、改造成矿作用及后期断裂作用的演化过程:燕山中晚期形成煤-铜-盐"三色建造"和盆地流体;喜马拉雅早期构造-热演化形成褶皱圈闭盆地流体,来自基底的富铜流体沿同生断裂(隐伏断裂)上升将一些亲铜元素从深部带入煤层而被吸附,形成富铜的还原性流体(H2O-SO2-CO2-CH4(C3H8-C2H6)-HSO4-HCO3-型),还原性流体沿次级断裂、隐伏断裂和层间断裂及轴面变形带上升,与大气降水深循环淋滤膏盐层形成高盐度的氧化性流体(H2O-SO2-CO2-N2-CO-HSO4-型)在砂(页)岩相遇时发生水-岩相互作用,并封闭于高孔渗的砂(页)岩储层,在褶皱翼部或核部的中细粒砂岩和层间断裂带中形成层状、似层状矿体;喜马拉雅中期由于构造改造,在更次级断裂带中形成脉状矿(化)体。所以,该类矿床是褶皱构造圈闭盆地流体-含矿岩相和构造裂隙封闭成矿流体定位成矿的产物,是铜矿源、构造与流体三者耦合作用的结果,更好地解释了矿床既沿褶皱分布又沿含矿层定位及矿物、元素分带的主要原因。故建立了该类矿床的构造-流体耦合成矿模型。Sandstone-type copper deposit is a typical species of ore deposits occuring in the continental facies red-bed basin of Chuxiong,China. During the dynamic evolution of tectonic-fluid-mineralization system,the deposits of this kind experienced three evolution stages：sedimentation-diagenesis metallization,reformation metallization,and late faulting process. Coal-copper-salt three-color sedimentary formation and basin fluid were formed during the Middle and Late Yanshan Period. Early Himalayan tectonic-thermal evolution of gave birth to basin fluid of folding traps. Chalcophile elements were carried from deep crust to and Absorbed by coal seam when Cu-bearing fluids of basin basement ascended along the contemporaneous faults,thus forming Cu-bearing reductive fluid [H2O-SO2-CO2-CH4（C3H8-C2H6）-HSO4^--HCO3^-]. The reductive fluid ascended along secondary faults,buried faults,interlayer faults and deformation band of axial plane,and reacted with oxidative fluid （H2O-SO2-CO2-N2-CO-HSO4^-） of high salinity within sandstone and shale,which resulted from deep cycling of meteoric water and leaching of gypsum bed,and trapped within sandstone reservoirs with high porosity and permeability. Stratiform and stratoid ore bodies formed within medium-and fine-grained sandstone in the flanks and core of folds and interlayered faults. The tectonic reconstruction resulted in the mineralization of vein-type ore bodies in the secondary faulting zone in the Middle Himalayan Period. Therefore,the deposit of this kind is not only the result of emplacement of the basin fluid and enclosed metallogenic fluid but also the coupling product of ore source,controlling tectonic and fluid. Our study can better explain the reason for the distribution of the deposit within folding and ore-bearing strata,and zonation of mineral and elements. A coupling model of tectonic-fluid metallogenesis for sandstone-type copper deposit in the Chuxiong Basin has been established.

关 键 词：矿床模型 构造-流体耦合成矿 砂岩型铜矿床 楚雄盆地 

分 类 号：P618.41[天文地球—矿床学]