【作者】 武鹏；

【导师】 徐学义； 李向民；

【作者基本信息】 长安大学 ， 矿物学、岩石学、矿床学， 2010， 硕士

【摘要】 北祁连造山带是我国及世界上最重要的块状硫化物矿床成矿省之一,近十几年来,以夏林圻为首的研究群体对北祁连山早古生代沟-弧-盆体系的建立和完善为北祁连山找矿突破提供了理论依据。与海相火山岩有关的VHMS空间展布上成群出现、分段集中等典型特征,成矿作用上具有多期次、多阶段物特征。由于自然条件制约,东沟铜矿研究程度较低,对于它的形成环境与成矿时代存在着不同的认识,影响了该矿床找矿工作的开展。本文在前人研究的基础上,利用已有的资料,对东沟铜矿开展野外调查与室内研究工作,重点对该区火山岩进行系统采样,进行同位素年代学及岩石地球化学研究,查明东沟矿区火山岩的形成时代和环境,研究该矿区的含矿岩石组合、矿床类型、矿床地质特征、控矿因素,建立其成矿模式,并对该地区找矿潜力进行分析。取得的主要认识如下：1、东沟矿区基性火山岩岩石地球化学研究表明,其具大洋中脊玄武岩(N-MORB)的地球化学特征,认为该矿床形成于大洋扩张脊环境。2、东沟矿床的成矿特征在容矿围岩、矿体形态、矿石类型、矿石矿物组成、围岩蚀变等方面均表现为“塞浦路斯型”矿床的特征,赋矿岩体为蛇绿岩上部的基性火山岩中,表明该矿为与蛇绿岩有关的塞浦路斯型矿床。3、锆石U-Pb年代学研究表明：东沟铜矿区含矿基性火山岩成岩年龄是499.8±2.0Ma (MSWD=2.5),形成于晚寒武世；而产于其中的东沟铜矿是该期火山作用引发的海底热液对流循环作用的产物,成矿作用的也发生于晚寒武世。4、流体包裹体研究认为该区成矿期石英中包裹体主要为气液两相包裹体,气液比低；气相成分主要以CO2为主,液相成分主要为H2O；成矿流体温度为150～200℃、盐度13～16%(NaCl)、密度为0.87～0.95g／cm3。更多还原

【Abstract】 North Qilian orogenic belt is most important province of massive sulfide deposit in China and the world. In the last decade, the establishment and improvement of the North Qilian Early Paleozoic trench-arc-basin system by research group led by Lin-Qi Xia provided a theoretical basis with prospecting in north Qilian mountains. The VHMS related to marine volcanic have characteristics spatial distribution of the clusters, the typical sub-focus, mineralization that has many of times, multi-phase material characteristics. Constraints due to natural conditions, Donggou copper have been less studied, and there are different perceptions on its formation environment and metallogenetic epoch affected the deposit prospecting work.In this paper, based on previous studies of the Donggou Copper Mine field we carried out investigation and laboratory research work which focusing on systematic sampling of the volcanic rocks, geochronology and isotope geochemistry of rocks, the formation of volcanic rock mining era and environment to study the mining of ore-bearing rock formation, deposit type, geological features, ore-controlling factors, to establish the metallogenic model, and exploration potential of the region. Main conclusions obtained as follows:1. Basic volcanic rocks of Donggou it has a mid-ocean ridge basalt (N-MORB) geochemical characteristics, that the deposit formed in an oceanic spreading ridge environment.2. Donggou mineralization in the ore-wall rock characteristics, ore bodies, ore type, ore mineral composition, rock alteration and so showed the "Cyprus-type" deposit characteristics, ore rock to ophiolite basic volcanic rocks in the upper part of that mine with the ophiolite the Cyprus-type deposits.3. U-Pb zircon geochronology indicates:the age of Donggou Copper ore volcanic rocks diagenetic is 499.8±2.0 Ma (MSWD=2.5), formed in the Late Cambrian; and copper produced in one of the Donggou is the role of volcanic seafloor hydrothermal convection caused by the role of the product cycle, mineralization also occurred in the late Cambrian. 4. Fluid inclusions showed that ore formation of inclusions in quartz are mainly gas-liquid two-phase inclusions, gas-liquid ratio is low; gas composition mainly CO2-based, liquid ingredients mainly H2O; forming fluid temperature 150～200℃, salinity 13～16%(NaCl), density of 0.87～0.95g/cm3.更多还原