四川省九龙县打枪沟锂铍矿床地质特征及找矿潜力研究

发布时间：2018-04-17 08:22

本文选题：伟晶岩型锂铍矿 + 矿床地质特征　；参考：《成都理工大学》2017年硕士论文

【摘要】：前人对川西伟晶岩型稀有金属矿的研究主要集中于可尔因、甲基卡等地,近年来,随着九龙县打枪沟矿区地质勘查工作的不断投入,取得了良好的找矿效果,但综合研究资料极为匮乏。因此我们有必要对其矿床地质特征、成矿来源和成矿作用进行系统的研究,探讨矿床成因模式,为指导矿床深部和区域稀有金属找矿提供基础理论依据。本文通过大量搜集文献资料,并开展详细的野外地质观察和室内的矿床学、矿物学以及地球化学、流体包裹体等方面的研究,首次较为系统的分析了打枪沟矿床地质特征,初步建立了该矿床伟晶岩型稀有金属矿成矿模式,评价矿床与地区伟晶岩找矿潜力,得出以下几点认识:1)矿区内伟晶岩脉围岩为石英闪长岩和石英片岩,岩脉的产出形态和密集程度显著受控于九龙向斜,并充填于其轴部的一系列裂隙节理中;从区域上看,伟晶岩类型有微斜长石伟晶岩、微斜长石-钠长石伟晶岩、钠长石伟晶岩及钠长石-锂辉石伟晶岩,并呈现以二云母岩体为中心典型带状空间分布的特点,矿区处在以钠长石-锂辉石伟晶岩为主的C带。2)矿区锂矿体主要赋存于钠长石-锂辉石伟晶岩脉中,伴生铍、铌、钽、铷、锡,以Ⅰ-1矿体最为典型,基本全脉矿化,与伟晶岩脉产状一致;矿石矿物以锂辉石、锂云母、绿柱石、铌钽铁矿、锡石为主,结构以粒状、交代结构为主,构造主要为块状、浸染状为主;矿(脉)体自交代作用强烈,常见电气石化、白(锂)云母化、钠长石化、云英岩化等,并体现了K-Na-Li的交代系列。3)通过对比研究区内岩体与伟晶岩的主、微量、稀土等地球化学特征表明:自正长岩-石英闪长岩-二云母花岗岩体-二云母花岗岩脉-伟晶岩脉,岩浆愈向富硅、富碱(钠代替钾)、富稀有元素、富挥发分,而贫稀土总量、钙、铁、镁(铁代替镁)的方向演化,稀土元素球粒陨石标准化分布曲线都为轻稀土富集右倾型,且变化趋势基本一致等特点,都相互验证和体现了同源岩浆分异,逐步演化程度变高的结晶分异过程。4)打枪沟矿区含矿伟晶岩的流体包裹体具有中低温、低压、中低盐度、形成深度较浅的特点,而流体成分富含挥发分和Na+,打枪沟矿床包裹体特征属于热液阶段包裹体特征,与伟晶岩熔融体的热液交代作用密切相关。5)矿床成矿物质来源于二云母花岗岩,为松潘-甘孜造山带两期构造运动引起的岩浆活动多期次结晶分异的产物,其残余熔浆富挥发分、碱质和稀有元素,向外迁移以结晶分异作用为主导,并在残余熔浆的自交代作用下在远离岩体的褶皱轴部围岩中发生稀有金属矿化。因此,打枪沟矿床的成因模式为岩浆结晶分异和热液交代成因。6)伟晶岩与岩体(脉)、构造的关系,其交代蚀变、地球物理、地球化学、特征矿物等特征可作为找矿标志。矿区中部、南部的找矿潜力大;九龙地区西部、打枪沟矿区西侧的花岗岩体内外接触带以及兰尼巴岩体以北的区域具有找矿前景。
[Abstract]:Previous studies of pegmatite rare metal deposits in western Sichuan are mainly focused on Kerin, methylka and other places. In recent years, with the continuous investment of geological exploration work in Taijianggou mining area of Jiulong County, good prospecting results have been achieved.However, comprehensive research data is extremely scarce.Therefore, it is necessary for us to make a systematic study on the geological characteristics, metallogenic sources and metallogenic processes of the ore deposits, and to discuss the genetic model of the deposits, so as to provide a basic theoretical basis for guiding the prospecting of the deep and regional rare metals of the deposits.In this paper, the geological characteristics of the Daganggou deposit are analyzed systematically for the first time by collecting a large amount of literature, and carrying out detailed field geological observation and laboratory studies of ore deposit, mineralogy, geochemistry, fluid inclusion, and so on.The ore-forming model of pegmatite type rare metal ore is established, and the prospecting potential of pegmatite in ore deposit and area is evaluated. It is concluded that the surrounding rock of pegmatite vein in the deposit is quartz diorite and quartz schist.The formation and density of the veins are significantly controlled by the Jiulong syncline and filled in a series of fracture joints at its axis. Regionally, pegmatite types include microplagioclase pegmatite, microplagioclase albite pegmatite,Albite pegmatite and albite spodumene pegmatite show typical zonal spatial distribution in the center of dimicite.The ore area is located in the C zone mainly composed of albite and spodumene pegmatite. 2) the Lithium orebody in the ore area mainly occurs in the albite spodumene pegmatite vein, accompanied by beryllium, niobium, tantalum, rubidium, tin, and I 1 orebody.The ore minerals are spodumene, spodumite, Beryl, niobium-tantalite, cassiterite, granular structure, metasomatic structure, block structure and disseminated structure.Common electrical petrifaction, white (lithium) mica, albite, quartz, etc., and reflect K-Na-Li 's metasomatism series. 3) through comparative study of the main and trace of rock mass and pegmatite in the area,The geochemical characteristics of rare earth elements indicate that since syenite, quartz diorite, dimite granite body, bimica granite vein and pegmatite vein, magma is rich in silicon, alkali (sodium instead of potassium, rich in rare elements, rich in volatile matter), and poor in total rare earth,The evolution of calcium, iron and magnesium (instead of magnesium), the normalized distribution curve of chondrites of rare earth elements are all light rare earth enriched right-dip type, and the variation trend is basically the same, all of them verify and embody the homologous magmatic differentiation.The fluid inclusions of pegmatite in Daganggou mining area have the characteristics of medium and low temperature, low pressure, low salinity and shallow formation depth, while the fluid composition is rich in volatilization and Na, while the fluid composition is rich in volatiles and Na, while the fluid inclusions are characterized by low temperature, low pressure and low salinity, and the fluid composition is rich in volatiles and Na.The characteristics of inclusions in Daganggou deposit belong to the characteristics of inclusions in hydrothermal stage, which are closely related to the hydrothermal metasomatism of pegmatite melts. 5) the ore-forming materials of the deposit are derived from dimicite granites.It is the product of multi-stage crystallization differentiation of magmatic activity caused by the two-stage tectonic movement of Songpan-Ganzi orogenic belt. The residual melts are rich in volatile, alkali and rare elements, and their outward migration is dominated by crystallization differentiation.The rare metal mineralization occurs in the surrounding rock of the fold axis far away from the rock mass under the self-metasomatism of the residual slurry.Therefore, the genetic model of the Daganggou deposit is magmatic crystallization differentiation and hydrothermal metasomatism. 6) the relationship between pegmatite and rock mass (vein, structure, metasomatic alteration, geophysics, geochemistry, characteristic minerals, etc.) can be used as a prospecting marker.The prospecting potential is great in the middle and south of the mining area, and in the west of Jiulong area, the inner and outer contact zone of granite in the west of Taganggou mining area and the area north of Laniba rock body.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.7

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