【作者】 郑明泓；

【导师】 邵拥军；

【作者基本信息】 中南大学 ， 矿产普查与勘探， 2011， 硕士

【摘要】 龙门山铜矿床位于扬子地块北缘下扬子台坳沿江断褶带中段的月山岩体内以及岩体与围岩的接触带中,是长江中下游铜铁成矿带的重要矿床之一。在对区域地质背景、矿床地质特征、矿床地球化学特征、成矿流体分析的基础上,开展了月山地区控矿因素、成岩机制、矿床成因等方面的研究。论文的研究成果与创新主要有以下几点：1、通过对区域地质背景的分析,研究了矿床地质特征,在此基础上,根据矿物共生组合关系,将龙门山铜矿床的成矿作用分为矽卡岩期和硫化物期；矽卡岩期分为早期矽卡岩阶段、晚期矽卡岩阶段、氧化物阶段；硫化物期分为石英硫化物阶段、铜铁硫化物阶段和碳酸盐阶段。2、对月山岩体的岩石化学特征、稀土元素和微量元素地球化学特征进行研究,表明月山岩体具富钠、钾的特征,同时富钙的特征也比较明显,属于中酸性、钙碱性岩体。岩体轻、重稀土分馏明显,轻稀土强烈富集,铈、铀异常不明显,且δEu与Si02含量呈负相关而与CaO呈正相关。3、月山岩体是龙门山矿床的成矿岩体,在分析其岩浆来源、构造环境及成岩过程的基础上,探讨了其成岩机制,指出月山岩体起源于深部的碱性玄武岩浆,在成岩过程中受到了硅质围岩和钙质围岩的同化混染,属于典型的AFC混合机制。4、对龙门山铜矿床岩体、蚀变岩、矿石及围岩稀土元素特征进行研究,得出矿体中的矽卡岩的配分曲线与较纯的岩体的基本趋势相同,表明本区矿体与岩体具有相同的岩浆来源和一致的岩浆演化途径。由岩体、蚀变岩、矽卡岩、矿石、围岩中Cu、Fe、Mn、Zn、Pb等元素含量分布规律可以看出靠近岩体的内接触带相对来说更有利于成矿,地壳的混染作用对成矿也有一定的影响。5、对龙门山铜矿床流体包裹体进行了较系统研究,得出该区流体包裹体均一温度主要介于191.3-441.3℃之间,大致可分为中、高两个温度范围,盐度变化范围大致也可分为高、中低两群,流体密度范围是：0.61-1.004g/cm3,属于中等密度流体。流体包裹体成分分析表明,成矿流体以水为主,液相成分中,阳离子主要有：Ca2+、Na+、K+,阴离子有：Cl-、SO42-、F-,气相成分主要是CO2,含有一定量的CH4和少量其他有机气体。成矿溶液属于H2O－Na+(Ca2+、K+)-Cl-(SO42-、F-)-C02体系。6、通过对矿床地质特征、地球化学特征、流体包裹体特征分析、控矿因素以及成岩机制的分析,龙门山铜矿床是与富硅富碱中酸性侵入岩有关的接触交代作用形成的矽卡岩型铜矿床。更多还原

【Abstract】 Longmenshan copper deposit is located in Yueshan rock mass which belongs to the middle of broken fold belt in northern margin of Yangtze block and contact zone between rock body and surrounding rock. This deposit is one of the most important deposits in the middle and lower Yangtze River copper metallogenic belt. Based on the analysis of the characteristics of geological background, geological of ore deposit, geochemical of deposit, metallogenic geologic condition and ore-forming fluids, then do the researches on the ore-controlling factors, rock-forming mechanism, the genesis of deposit and etc. The main achievements are made as follows:1. Though the researching the characteristics of geological background, and the geological characteristics of deposit, and then divides the mineralization of Longmenshan copper deposit into skarn stage and sulfide stage two periods by the relation of mineral paragenetic association. And skarn stage can be divided into three phase, namely: early skarn phase, terminal skarn phase, oxide phase; sulfide stage can be divided into three phase, namely:quartz sulfidic phase, sulfidic stage and carbonate phase.2. According to petrochemical characteristics of magmatic rocks, trace elements, REE geochemiscal characteristics and diagnostic fluid inclusions characteristics of Yueshan rock mass, we draw the conclusion that the Yueshan rock body has the character of rich kalium and natrium, as well as the character of rich calcium is obvious. Yueshan rock mass is belong to intermediate-felsic and calc-alkaline rock mass. Its light-heavy rare earth elements’ Fractionation is obvious; it is strongly enriched in light rare earth elements. Ce、Eu anomaly is not obvious. The relationship between content ofδEu and SiO2 is negative correlation, and the relationship between content ofδEu and CaO is positive correlation.3. Yueshan rock body is the ore-forming rock body of Longmenshan copper deposit. On the basis of the analysis on the magma sources、tectonic environment and rock-forming process, combined with achievements of ore-forming mechanism, we draw the conclusion that Yueshan rock body roots in the deep-seated alkaline basaltic magma. The rock—forming process has undertaken two diferent degrees of assimilation and contamination. The rock-forming model belongs to the typical AFC mechanism.4. Though the researching of the REE geochemiscal characteristics and diagnostic fluid inclusions characteristics of rock mass, alter-rocks, ore and surrounding rock, we draw the conclusion that distribution patterns trend of ore and fresh rock mass of this area is the same. It shows that ore and fresh rock mass of this area have the same magma sources and magmatic evolution approach. The content distribution law of Cu, Fe, Mn, Zn, Pb in the rock mass, alter-rocks, ore and surrounding rock shows that the inner contact zone Close to the rock is more benefited for ore-forming, as well as the contamination of the crust has certain influence on ore-forming.5. By systemic researching the diagnostic fluid inclusions of the Longmenshan copper ore, we find that homogenization temperature is between 191.3～441.3℃, it can be divided into high and intermediate Temperature, the salinity can be also divided into two groups-high and medium-low. The density range in 0.61-1.004g/cm3, belongs to the medium-low-density fluid. The gas phase is mainly composed of H2O and CO2, with minor organic gas; the main anions in the liquid composition are Cl-, NO3- and SO42-, and the cations are Ca2+, Na+ and K+. The ore-forming solutions belong to the H2O-Na+(Ca2+, K+)-Cl-(SO42-,F-)-CO2 type.6. By analysing the ore deposit geologic characteristic, geochemical characteristic, diagnostic fluid inclusions characteristic, ore-controlling factors and rock-forming mechanism, we draw the conclusion that Longmenshan copper deposit is a contact metasomatic copper deposit which relates with silicon-rich and alkaline-rich intermediate-acid diorite.更多还原