新疆萨热克砂砾岩型铜矿区碎裂岩化相特征

摘要

Sereke glutenite-type Cu deposit in Xinjiang is controlled by Mesozoic intracontinental pull-apart basin in Serekebayi.The orebodies are mainly hosted in Upper Jurassic Kuzigongsu Formation alteration and conglomerate.Because of the strong alteration at the later stage,the cataclastic lithofacies has significant controlling on Sereke glutenite-type Cu deposit. The cataclastic lithofacies forms in the process of basin reformation,and has the strong coupling between fissure and basin fluid.Cataclastic lithification-fissure structure is the migration channel and reservoir structure of the superposition mineralization of deep-source thermal fluid.The macroscopic characteristics of cataclastic lithofacies are mainly consequent cracked fissure zone+shear cracked fissure zone+cataclastic lithification+bituminization+net vein copper sulfide.The types of microscopic fissures are mainly the fissure inside gravel,the fissure around gravel and the fissure across gravel;the fissures are filled with chlorite,chalcocite,asphaltenes,quartz and iron carbonate.The densities of fissures increase from the ancient stratum to nowadays.The fissure permeability and gas logging permeability show that the fissure permeabilities of Upper Jurassic Kuzigongsu Formation ore-bearing strata are higher than the others,and the fissures provide migration pathway and storage space for ore-forming fluid in basin.%新疆萨热克砂砾岩型铜矿床受萨热克巴依中生代陆内拉分盆地控制,矿体主要赋存于上侏罗统库孜贡苏组蚀变杂砾岩层中.受后期碎裂岩化相强烈改造,碎裂岩化相对萨热克砂砾岩型铜矿床具有明显控制作用.碎裂岩化相形成于盆地改造过程,并具有裂隙-盆地流体强烈耦合作用.碎裂岩化-裂隙构造是深源热流体叠加成矿的运移通道和储矿构造.碎裂岩化相宏观特征以顺层裂隙破碎带+切层裂隙破碎带+碎裂岩化+沥青化+网脉状铜硫化物为主.微观裂缝类型主要为砾内缝、砾缘缝与穿砾缝,沿裂隙和裂缝充填绿泥石、辉铜矿、沥青质、石英和铁碳酸盐等.地层从老到新,裂缝密度整体呈现由低到高的特征.裂隙渗透率和气测渗透率表明上侏罗统库孜贡苏组含矿层的裂隙渗透率比其他非含矿层更高,裂隙和裂缝为盆地成矿流体提供了运移通道和储矿空间.