新疆西天山松树沟铜矿床成因矿物学研究.doc

新疆西天山松树沟铜矿床成因矿物学研究 【中文摘要】松树沟铜矿在区域上位于玉希莫洛盖达坂巴腊陶NWSE向构造带,属于阿吾拉勒铁铜成矿带东延部分。该矿区的北北东向断裂是主要控矿构造,与二叠纪花岗斑岩共同控制松树沟铜矿的产出。本文在对矿区地质背景、矿体地质特征、围岩蚀变、矿石类型、矿物共生组合及其分带等特征的研究基础上,对该矿区成矿作用的期次、阶段及矿物天生顺序进行了划分,并运用现代测试技术对矿区内具有标型特征的黄铁矿和黄铜矿的微量元素和稀土元素、绿泥石的化学成分和晶体化学特征、石英中流体包裹体特征等进行了对比分析研究。黄铁矿在该矿床中分布广、从早期到晚期均有形成,根据矿化蚀变期次及矿物共生组合,可将黄铁矿分为三个世代PyⅠ、PyⅡ和PyⅢ,黄铁矿的微量元素的分析结果显示本矿区黄铁矿为热液成因。黄铁矿和黄铜矿中稀土元素分布不均,表现为Eu和Ce亏损。黄铁矿硫同位素测试结果接近于公认的上地幔范围,表明成矿物质中的硫质可能来源于岩浆。绿泥石是该铜矿床中主要的蚀变矿物,分布范围广,根据其产出特征及矿物共生组合关系,可分为交代型和充填脉型两种,其中,交代型绿泥石与矿化相关,其含铁量较低,晶体化学式中铁的原子数为1.504～1.688,充填脉型的绿泥石含铁量较高,晶体化学式中铁的原子数为1.935～2.178,矿区内绿泥石的铁含量的明显差异性可以作为寻找铜矿化的标型特征。计算出绿泥石形成的温度为288～324℃。矿床中的石英所含的流体包裹体有气液两相包裹体和含子矿物的多相包裹体。气液两相包裹体含量较多,其中,气液两相包裹体形态呈圆粒状、米粒状和不规则状等;含子矿物的多相包裹体形态呈浑圆状和不规则状。包裹体的均一温度变化范围较宽,从106～345℃,含盐度NaCl变化于5.41～42.04 wt之间,流体密度值为0.75～1.15 g/m-3,估算成矿压力为30～91Mpa,成矿深度为996-3049M。; 【Abstract】 The Songshugou copper deposit is situated in the tectonic belt of Yuximologaidaban , Balatao NW, SE in area, which belongs to the east postpone part of Iron and copper mineralization belt. Owing to the mining area NNE direction fracture is to control the structure that mineral deposit s mainly, Together with permian granitic porphyry controls the output of Songshugou copper deposit.Based on study on geological background of the copper deposit, geological characteristics of orebody, surrounding rock alteration, ore type, and mineral paragenesis combination, this *** has partitioned the mineralization periods, phases and ing order of mineral, and also done a contrast research on trace element and REE of typomorphic pyrite, chemical composition of chlorite and crystal-chemical characteristics, fluid inclusions feature in quartz through using modern testing s.According to mineralization periods and intergrowth combination relations, pyrite can be divided into three generations. The analysis results of Pyrite’s main trace elements show that the Pyrites in this ore district is attributed to hydrothermal genesis type. The Maldistribution of REE in Pyrite manifests the loss of Eu and Ce. The testing result of sulphur isotope is close to the recognized upper mantle range, and indicates that the sulphur of mineral perhaps is derived from magma.The chlorite, with a wide distribution range, is the main alteration mineral of this copper deposit. According to its producing characteristic and colacobisis combination relation, chlorite can be divided into two types, one is metasomatic type, the other is filling vein type. The chlorite of the metasomatic feldspathic type is relevant to mineralization, with lower content of icon and atomicity of Fe ranging from 1.476 to 1.639 in crystal chemical ula. While the chlorite of veil type bear higher icon content and atomicity of Fe ranging from 1.879 to 2.143. The obvious difference of icon contents in this ore district can be regarded as the typomorphic peculiarity for searching for copper mineralization. The ing temperature of chlorite is calculated to be from 288℃to 324℃.Research on fluid inclusions in quartz of this ore district indicates the two main types, which is gas-liquid inclusions and multiphase inclusions with daughter mineral,the er inclusions shapes look like circle granular, granular and irregular, while the latter look like round and irregular. Homogeneous temperature of the inclusions varies ranging from 106～345℃, salinity NaCl varies from 5.41 to 42.04 wt , fluid density value is from 0.75 to 1.15g/m-3, the range of ore-ing pressure is estimated to be from 30 to 91Mpa, ore-ing depth is 996-3049M.