寄主岩浆硫化物和氧化物矿床的镁铁质-超镁铁质岩体对比分析与成矿过程评述  

Comparison of host magmatic sulphide and oxide deposits of mafic-ultramafic intrusions and review the mineralizing process

作　　者：姜常义[1,2] 夏昭德[1] 凌锦兰[1] 夏明哲[1,2] 卢荣辉[1] 郭芳放[1] 

机构地区：[1]长安大学地球科学与资源学院,西安710054 [2]西部矿产资源与地质工程教育部重点实验室,西安710054

出　　处：《岩石学报》2011年第10期3005-3020,共16页Acta Petrologica Sinica

基　　金：国家自然科学基金面上项目(40872070);国家自然基金重点项目(40534020);长安大学中央高校基本科研业务费专项资金资助项目(CHD2010ZY008)联合资助

摘　　要：镁铁质-超镁铁质岩体是世界上岩浆硫化物(Ni-Cu-PGE)和氧化物(Fe-Ti-V-P)矿床的主要载体。全球主要岩浆硫化物和氧化物矿床均可以产于大火成岩省、克拉通区的裂谷带或伸展环境、褶皱带内的后碰撞伸展环境。寄主岩浆硫化物矿床的岩体规模相差甚大(从6×104km2到<0.1km2),既有超镁铁质岩石组合也有镁铁质岩石组合,但其原生岩浆主要为拉斑玄武质岩浆。含镍铜的铂族元素矿床主要赋存于规模很大的层状岩体中,而镍铜硫化物矿床主要赋存于小岩体中。寄主钒钛磁铁矿或磁铁矿矿床的岩体主要是以辉长岩为主的层状杂岩体。寄主钛铁矿-磷灰石矿床的岩体均为层状的斜长岩-纹长二长岩-紫苏花岗岩岩体。尽管其岩石组合相差很大,但其原生岩浆均属拉斑玄武质。寄主硫化物矿床的岩体相对富Si、Mg、Cr、Ni,而寄主氧化物矿床的岩体相对富Fe-Ti-P-V,造岩矿物晶体化学也反映了这种差异。对全球主要含矿岩体的对比分析表明,导致这种反差的主要控制因素应该是岩浆生成时的压力状态,源区性质和熔融程度的差异可能只在局部范围内起作用。对岩浆硫化物矿床成矿过程的认识集中体现在金川模式和岩浆通道模式上,对岩浆氧化物矿床成矿过程的认识体现在氧化物和磷灰石是堆晶相还是从不混溶的矿浆中结晶的。对比分析表明,成矿过程具有多样性,试图用一种模式概括所有同类矿床成矿过程的想法未必可取。毫无疑问,适宜的氧化还原环境是形成岩浆矿床的必要条件,伴随岩浆演化及成矿过程的氧逸度变化及其诱因问题尚待进一步探索。Mafic-ultramafic intrusion is a main vector of magmatic sulfide（Ni-Cu-PGE） deposits and oxide（Fe-Ti-V-P） deposits in the world.The world＇s major magmatic sulfide deposits and magmatic oxide deposits can occur in large igneous provinces,cratonic rift zone areas or extension setting,stretching post-collisional environment of the folded belt.The scale of host rock of magmatic sulphide deposits varies greatly（from 6×104km2 to 0.1km2）,the rock associations have ultramafic rocks and mafic rocks,but their primary magma are mainly tholeiitic magma.The PGE deposits bearing Ni-Cu host mainly in large-scale stratified intrusions,while the Ni-Cu sulfide deposit occurs in small intrusions.Vanadium-titanium magnetite or magnetite deposits host mainly in layered gabbro complex and ilmenite-apatite deposits are host in layered intrusions with anorthosite-mangerite-charnockite associations.Although the rock composition varies greatly,but its primary magma belongs to tholeiitic.Host rock of sulphide deposit is relatively rich in Si,Mg,Cr,Ni,while host rock of oxide deposits is relatively rich in Fe-Ti-P-V,rock-forming mineral crystal chemistry also reflects the difference.The critical factor of the contrast is the pressure of magma generation,whereas the difference in the magma source and the extent of melting may only play a role in the local area.The view for the ore forming processes of magmatic sulfide deposits are represented by the Jinchuan model and magma conduit model,and that of oxide deposit by whether oxide and apatite are cumulates or crystals from immiscible oxide liquid.Comparative analysis shows that the mineralizing process is complex,and it may not be preferable that trying to use a model to interpret the process of all the similar deposits.There is no doubt that an appropriate redox environment is the necessary conditions for the formation of magmatic deposits.Accompanied by crystallization of magma and mineralizing process of change in oxygen fugacity and incentive problems remain to be explored f

关 键 词：岩浆矿床 岩体类型 岩石组合 地球化学 原生岩浆 成矿过程 氧逸度 

分 类 号：P588.125[天文地球—岩石学] P611.11[天文地球—地质学]