【摘要】 金川岩浆铜镍硫化物矿床是世界第三大岩浆型镍矿床。近年来，关于金川矿床成因机制的讨论一直存在争议，目前流行的成矿模型主要有以下两种:(1)岩浆通道堆积模型;(2)深部熔离-多次贯入模型。为探讨金川岩浆铜镍硫化物矿床成因，通过岩相学、主微量元素分析以及Fe同位素分析等方法，对矿石中镍黄铁矿的结构状态、共生组合与成分特征进行研究，探讨了矿物成因及成矿过程。金川矿床中存在两类镍黄铁矿，早阶段镍黄铁矿(Pn-Ⅰ)放射状裂隙比较发育，一般呈自形-他形粒状，粒度为0.2～2.5mm，与磁黄铁矿紧密连生，属于典型的硫化物矿浆结晶阶段形成的镍黄铁矿;晚阶段镍黄铁矿(Pn-Ⅱ)与磷灰石、云母和方解石等流体晶矿物共生，接触边缘平直，较自形，呈颗粒状、团块状，粒径在0.05～0.2mm之间，具相对高的Ni、Co、P等元素含量，为挥发分流体和硫化物矿浆相互作用阶段形成的镍黄铁矿。早期形成的Pn-Ⅰ裂隙比较发育，表明其经历了流体超压作用，Pn-Ⅱ与流体晶矿物共生，接触边缘平直，这些特征说明有流体参与了成矿过程。深源流体的加入是Ni、Co等关键金属元素迁移与富集的重要因素，可能存在富Cl的深源流体注入岩浆房，对硫化物矿浆向上运移并形成经济矿体起到关键驱动作用。更多还原

【Abstract】 The Jinchuan magmatic Cu-Ni sulfide deposit is the world’s third-largest magmatic nickel deposit. In recent years,discussions on the genetic mechanism of the Jinchuan deposit have been controversial. Currently,two prevailing metallogenic models exist:( 1) Magmatic conduit accumulation metallogenic model and( 2) deep segregation-injection metallogenenic model. To investigate the genesis of the Jinchuan magmatic Cu-Ni sulfide deposit,petrography and major-trace element analysis and Fe isotope analysis were employed to study the textural state,paragenetic association,and compositional characteristics of pentlandite in the ores,thereby elucidating the mineral genesis and metallogenic processes. The Jinchuan deposit contains two types of pentlandite: Early-stage pentlandite( Pn-Ⅰ) exhibits well-developed radial fractures,generally occurring as euhedral to anhedral granular crystals( 0. 2 ～2. 5 mm),and is intimately intergrown with pyrrhotite. It belongs to pentlandite formed during the crystallization stage of a typical sulfide magma. Late-stage pentlandite( Pn-Ⅱ) coexists with fluid-crystallized minerals such as apatite,mica,and calcite. It displays straight contact boundaries,is relatively euhedral,and occurs as granular aggregates or nodules( 0. 05 ～ 0. 2 mm). Pn-Ⅱ shows relatively high concentrations of Ni,Co,and P,representing pentlandite formed during the interaction stage between volatile-rich fluids and sulfide magma. The well-developed fractures in early-formed Pn-I indicate its experience of fluid overpressure. The coexistence of Pn-Ⅱ with fluid-crystallized minerals and its straight contact boundaries collectively demonstrate fluid involvement in the metallogenic process. The addition of deep-source fluid is an important factor in the migration and enrichment of key metal elements such as Ni and Co. There may be deep-source fluid rich in Cl injected into the magma chamber,which plays a key driving role in the upward migration of sulfide magma and the formation of economic ore bodies.更多还原