青海玉树查涌铜多金属矿床地质特征及矿化富集规律

发布时间：2018-02-27 11:02

  本文关键词： 矿床地质 矿床成因 矿化富集规律 查涌铜多金属矿床　出处：《吉林大学》2017年硕士论文　论文类型：学位论文

【摘要】：查涌铜多金属矿床位于青海省玉树地区,大地构造位置属特提斯—喜马拉雅构造域一部分,位于冈瓦纳大陆与欧亚大陆碰撞挤压地带,属于三江多金属成矿带。矿区出露地层主要为三叠系巴塘群第二岩组。矿区发育不同时期的岩浆岩,出露面积均较小,以侵入岩为主,包括晚印支期花岗闪长岩、燕山期石英闪长岩和喜山期辉长岩(33.1±1.8Ma)。其中脉状铜矿体穿切该辉长岩体,间接限定了成矿时代,并且岩石地球化学研究表明岩体具大陆溢流拉斑玄武岩特征,形成于印度板块与欧亚板块碰撞后伸展环境。目前查涌铜多金属矿区圈定了4个主矿体,包括CuI-1、CuI-3、CuI-4、Cu-Pb-Zn-Ag-MoI-5。主要金属矿物包括黄铜矿、黄铁矿、方铅矿、闪锌矿和少量辉钼矿等。矿石结构主要包括固溶体分离结构和交代结构等,矿石构造以浸染状构造、脉状构造及交错网脉状构造等为主。同时相应围岩蚀变主要有钾化、黑云母化、硅化、绢云岩化和碳酸盐化,呈线性蚀变特征,显示高温-低温的变化特征。利用槽探、钻探工程进行揭露,发现多条脉状、透镜状矿体,受区内北西西向断裂构造控制明显。通过对成矿流体研究,表现为包裹体类型简单,主成矿阶段流体显示中高温(363.7~415.9℃)、低盐度(0.53~6.29wt%)、低密度(0.53~0.59g/cm3)的特点,通过激光拉曼成分分析,成矿流体中富含H2O、CH4、N2和少量CO2,属于H2O-NaCl-CH4-N2±CO2体系。计算求出成矿压力50~60MPa,对应深度5.63~6.22km。硫同位素研究表明成矿流体主要来源于地层还原硫(三叠系地层),并混入部分岩浆硫。铅同位素显示主要来源于上地壳,并混入少量下地壳铅。此次尚未对成矿年龄进行测定,但通过测定辉长岩体成岩年龄限定了成矿年龄,属于喜山期。矿床形成构造背景为印度板块与欧亚板块碰撞后伸展环境。通过上面诸多方面研究,进而确定其成因类型为中高温热液脉型铜多金属矿床。通过对查涌铜多金属矿床矿化富集规律研究发现,构造控矿为该地区铜多金属矿床最为显著特征。具体表现为:走向上矿体相对富集于近东西向断裂带内及近东西向与北西向断裂带交汇处。垂向上矿体相对富集在断裂产状变缓部位,从深部向浅部依次为Mo-Cu-Pb、Zn、Ag,呈现一定的元素分带。横向上矿脉集中分布呈一系列北东向等距相间平行分布。侧伏规律上矿脉总体向NWW方向侧伏,从东向西呈现Mo-Cu-Pb、Zn、Ag分带,其中以西Pb、Zn、Ag品位较高,为进一步找矿方向,以东深部岩芯具良好辉钼矿化信息,指示深部存在隐伏中酸性岩体。
[Abstract]:The Chayong copper polymetallic deposit is located in the Yushu area of Qinghai Province. The geotectonic position is part of the Tethys Himalayan tectonic domain and is located in the collision and compression zone between Gondwana and Eurasia. It belongs to the Sanjiang polymetallic metallogenic belt. The exposed strata of the mining area are mainly the second rock formation of the Triassic Batang group. The magmatic rocks developed in different periods of the mining area are relatively small, with intrusive rocks, including the late Indosinian granodiorite. The Yanshanian quartz diorite and the Himalayan gabbro (33.1 卤1.8 Ma), in which the vein-like copper ore body pierced the gabbro body, indirectly defined the metallogenic age, and the petrogeochemical study indicated that the rock mass has the characteristics of continental spillway tholeiite basalt. Formed in the extensional environment after the collision of the Indian plate and the Eurasian plate. At present, four main orebodies have been delineated in the Chayong copper polymetallic ore area, including CuI-1C CuI-3U CuI-4U Cu-Pb-Zn-Ag-MoI-5. the main metal minerals include chalcopyrite, pyrite, galena, etc. The ore structure mainly consists of solid solution separation structure and metasomatism structure, ore structure is dominated by disseminated structure, vein structure and staggered vein structure, and the corresponding wall rock alteration is mainly potassium, the ore structure is mainly composed of solid solution separation structure and metasomorphic structure, and the ore structure is dominated by disseminated structure, vein structure and staggered vein structure, etc. Biotite, silicification, sericite and carbonization show linear alteration characteristics, showing the characteristics of high-temperature and low-temperature variations. By means of trough exploration and drilling engineering, many veins and lenticular orebodies have been discovered. It is obviously controlled by the NW-trending fault structure in the area. By studying the ore-forming fluids, the fluid inclusions are characterized by simple inclusions. In the main ore-forming stage, the fluid shows the characteristics of moderate high temperature (363.7U 415.9 鈩，

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