云浮硫铁矿是位于钦杭结合带南段的超大型硫铁矿床,长期以来对其成因类型及成矿构造背景存在争议.基于矿床地质和岩相矿相学观察,应用最新的扫描电镜能谱技术(SEM-EDS)对其进行了细致研究.研究表明,云浮硫铁矿床黄铁矿矿石结构可分为条带状、浸染状、块状和脉状4种类型.手标本及镜下观察发现,条带状矿石存在揉皱构造,块状矿石中存在两种不同粒度的黄铁矿,黄铁矿细脉普遍存在于各种矿石中.扫描电镜观察和能谱分析显示,条带状矿石中黄铁矿主要呈立方体自形晶,立方体表面生长层发育平整,边缘平直,晶体按照多个层位同时堆积的方式生长,方铅矿等伴生矿物晶形也较好;浸染状矿石中黄铁矿粒度要大于条带状矿石中黄铁矿,但生长层不如后者平整;块状矿石中黄铁矿紧密接触,黄铁矿表面呈贝壳状断口,晶体边缘较难分辨,但样品表面也常见到近八面体晶形的晶体;脉状矿石中黄铁矿粒度较大,伴生有方铅矿等金属矿物,但由于生长空间的限制,晶形为半自形-他形.认为云浮硫铁矿具有2期叠加成矿的特点,为改造加富的热水喷流沉积矿床.喷流沉积阶段形成条带状和浸染状黄铁矿,其成矿温度较低,成矿环境相对平静.后期热液叠加富集阶段形成块状和脉状黄铁矿,其成矿温度较高.%Yunfu pyrite deposit is a large-scaled deposit,located in the southern section of Qinzhou-Hangzhou Metallogenetic Belt.Ore textures in the Yunfu pyrite deposit can be classified into four types,including the banded,disseminated,massive and veiny.The specimens and microscopic observation show that banded ores suffered the subsequent crumpled structures,the massive ores are composed of two different particle sizes of pyrite,and the pyrite vein cut across all above-mentioned ores.The SEM (Scanning Electron Microscope) coupled with EDS (EnergyDisperseSpectroscopy) measurements are carried out to yield the micro-fabric characteristics of all four types of pyrite.The pyrite grains in the banded ores present as cube euhedral crystal with the growth layer developed,implying that the crystal grows accompanying with multiple layer accumulation.The granularity of pyrite in the disseminated ores is commonly bigger than in banded ores,but the growth layer is inferior to the latter.The pyrite grains in the massive ores contact closely with conchoidal fracture developed on the surface,and therefore their crystal edges are difficult to be distinguished.The particle size of pyrite in the veiny ores is the largest among the four types of ores.The crystal shape presents as hypidiomorphic-xenomorphic implicating the limited growth space.It is conclude that the Yunfu pyrite deposit was developed with two main stages of mineralization,including an earlier exhalative sedimentary mineralization overprinted by subsequence metamorphism and deformation.The exhalative sedimentary stage is presented by the formation of banded and disseminated pyrites,whereas the later stage of hydrothermal superposition formatting is characterized by massive and veiny pyrites.
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