青海沱沱河地区楚多曲铅锌矿控矿构造特征和矿床成因研究

发布时间：2018-01-13 08:24

本文关键词：青海沱沱河地区楚多曲铅锌矿控矿构造特征和矿床成因研究　出处：《吉林大学》2016年硕士论文　论文类型：学位论文

【摘要】：楚多曲铅锌矿床是近年来在沱沱河地区发现的大型铅锌矿床之一,(333+334)Pb金属量40.25万吨、Zn金属量11.27万吨、Cu金属量0.92万吨,具有巨大的找矿潜力,但是矿床成因类型不确定和控矿构造样式模糊等因素严重制约了找矿突破,因此十分有必要对该矿床进行全面深入的研究,为沱沱河地区找矿突破提供基础参考。本论文在野外调查基础上,充分查明楚多曲铅锌矿区域地质背景、矿区地质特征和矿床地质特征,对矿床进行了流体包裹体、同位素地球化学等方面的研究,查明了成矿流体成分和成矿流体演化过程,明确了矿床成因。楚多曲铅锌矿床的矿体赋存地层主要为夏里组(J2x),其次是索瓦组(J3s),主要赋存于碎裂泥晶粉晶灰岩、碎裂长石石英砂岩中,灰岩中矿化明显好于砂岩,灰岩提供了良好的成矿环境和赋矿空间。矿体产于NWW向断裂破碎带内,矿体主要呈似层状、脉状。沱沱河盆地的NWW向Ⅰ级断裂为区内导矿构造,NWW向Ⅰ级断裂派生的NWW向Ⅱ级张扭性断裂为区内容矿构造。控矿构造形成于古近纪始新世大陆碰撞造山后拉张环境,而非前人认为的成矿受推覆构造控制,成矿与沱沱河地区新生代大规模的钾质-超钾质岩浆活动关系密切,与钾质-超钾质浅成侵入体密切相关。楚多曲铅锌矿床矿石矿物主要有黄铁矿、黄铜矿、方铅矿、闪锌矿、褐铁矿、蓝铜矿、硫砷铜银矿和镜铁矿等;脉石矿物主要为石英、方解石、重晶石、石膏和少量绢云母等。矿石结构主要有自形-半自形粒状结构、他形粒状结构、包含结构、碎裂结构、残留结构和假象结构等。矿石构造主要有块状构造、角砾状构造、脉状-网脉状构造、浸染状构造和条带状构造等。围岩蚀变主要有碳酸盐化、重晶石化、绿帘石化、绢云母化、硅化和伊利石化等。楚多曲铅锌矿区内存在明显的矿化分带:南部为成矿Ⅰ阶段偏高温的石英-镜铁矿组合矿化带;北部为成矿Ⅱ、Ⅲ阶段方解石-方铅矿-闪锌矿-黄铜矿中低温组合矿化带。成矿过程分为3个阶段,以石英-镜铁矿组合(第Ⅰ阶段)、石英-重晶石-多金属硫化物组合(第Ⅱ阶段)和碳酸盐(第Ⅲ阶段)为标志。流体包裹体以气液两相为主,成矿压力(主成矿阶段)范围15.66~29.42 MPa(平均值21.63 MPa),成矿深度(主成矿阶段)1.57~2.94 km(平均值2.16 km),主成矿阶段(Ⅱ阶段)流体具有中低温(182℃~273℃)、中低盐度(4.01%~14.94%)、低密度(0.82g/cm3~0.98g/cm3)的特征,从早到晚温度、压力和盐度逐渐降低。成矿Ⅰ阶段,成矿流体温度较高,在氧化条件下,形成镜铁矿等矿物,晚期开始有黄铁矿、黄铜矿沉淀。成矿Ⅱ阶段,最初大量硫化物的沉淀以及浅部大气水的加入使得流体变得氧化,重晶石、石英等开始大量结晶。随着温度降低,重晶石、石英等结束结晶,成矿流体转变为中性还原流体,黄铁矿、黄铜矿、闪锌矿、方铅矿等矿物开始沉淀。成矿Ⅲ阶段,成矿流体由中性还原流体向氧化流体转变,形成网脉状方解石和针状石膏。碳、氢、氧同位素特征均表明成矿流体主要来自岩浆热液,随着成矿作用进行,成矿晚期流体有大气降水的参与,成矿流体具有混合来源特征,与MVT铅锌矿床成矿流体来源于盆地卤水不同。硫同位素特征指示,成矿物质中的硫主要来自相对单一岩浆源。铅同位素结果表明,楚多曲铅锌矿床铅具有混合铅特征,以壳源铅为主混合少量深源地幔铅,混合由俯冲造山作用导致,主要来源于与岩浆作用关系密切的新生代火山岩,与硫同位素反映的成矿物质来源一致。综合分析认为,楚多曲铅锌矿床属于中温热液脉型铅锌矿床,成矿与沱沱河地区新生代大规模的钾质-超钾质岩浆活动关系密切,受NWW向断裂构造控制,控矿构造形成于古近纪始新世大陆碰撞造山后拉张环境。
[Abstract]:In the Chu lead-zinc deposit is one of the large lead-zinc deposit found in Tuotuohe area in recent years, (333+334) Pb metal volume of 402 thousand and 500 tons, 112 thousand and 700 tons of metal Zn, Cu metal volume of 9 thousand and 200 tons, with great prospecting potential, but the genesis types of uncertain structure and ore sample fuzzy factors have seriously restricted the prospecting breakthrough, so it is very necessary to conduct a comprehensive in-depth study of the deposit, as the Tuotuohe area of prospecting breakthrough. This thesis provides the basis reference on the basis of field investigation, fully Chamingchuduo Qu lead-zinc mine regional geological background, geological features and geological features of the deposit, fluid inclusion, isotope geochemistry so, find out the composition of the ore-forming fluids and ore-forming fluid evolution, the genesis of the deposit. The ore body formation in the Chu lead-zinc deposit is mainly in summer group (J2x), followed by cable Watts group (J3s), occurs mainly in the fractured limestone micrite powder, cataclastic feldspar quartz sandstone, limestone mineralization was significantly better than that of sandstone, limestone provides good metallogenic environment and ore bearing space. The orebodies occur in the NWW fault fracture zone, the ore body mainly stratoid and vein Tootoo. The NWW river basin to grade fault zone ore structure NWW to grade NWW to grade II fracture derived transtensional fault zone for content bearing structures. The ore controlling structure formed in the Eocene continental collision post orogenic extensional environment, rather than forming previously considered by nappe tectonic control the relationship between the new generation system, large-scale ULTRAPOTASSIUM magmatism mineralization and Tuotuohe area closely, closely related with body ULTRAPOTASSIUM shallow intrusive. Chu multiloop lead-zinc deposit, the ore minerals are mainly pyrite, chalcopyrite, galena, sphalerite, limonite, azurite, sulfur and arsenic copper silver mirror Iron ore; gangue minerals are mainly quartz, calcite, barite, gypsum and a small amount of Sericite. Ore textures are mainly euhedral and subhedral granular structure, xenomorphic granular structure, including structure, cataclastic structure, residual structure and false structure. The main ore structures are massive structure, brecciated structure, vein - net vein structure, disseminated structure and banded structure. Wall rock alteration are mainly carbonate, baritization, epidotization, sericitization, silicification and illite etc. in lead-zinc mining area in the memory of Chu obvious mineralization zoning: Southern metallogenic stage of partial high temperature quartz hematite combination the northern ore mineralization belt; II, III stage calcite galena sphalerite chalcopyrite mineralization belt. Low temperature combined mineralization process is divided into 3 stages, with quartz and hematite combination (the first stage), quartz and barite polymetallic sulfide assemblage (II (III) stage and carbonate stage) as a symbol. The gas-liquid two-phase fluid inclusions in the main metallogenic pressure (main metallogenic stage) 15.66~29.42 MPa (average 21.63 MPa), metallogenic depth (main metallogenic stage) 1.57~2.94 km (average 2.16 km), the main mineralization stage (stage II) fluid with low temperature (182 DEG ~273 DEG), low salinity (4.01%~14.94%), low density (0.82g/cm3~0.98g/cm3) characteristics, night temperature, pressure and salinity decreased gradually. Metallogenic phase I, ore-forming fluid with high temperature, under oxidizing conditions, forming minerals such as hematite, pyrite chalcopyrite precipitation started late, metallogenic stage. Initially. A lot of sulfide precipitation and shallow meteoric water makes the fluid become oxidized, barite, quartz etc. began to crystallization. With the decrease of temperature, barite, quartz and other end of crystallization, the ore-forming fluid into neutral reduction fluid, yellow Iron ore, chalcopyrite, sphalerite, galena and other mineral precipitation. Metallogenic stage III, metallogenic fluid from the fluid fluid transition to neutral reduction oxidation, the formation of stockwork calcite and gypsum. Acicular carbon, hydrogen and oxygen isotopic characteristics show that the ore-forming fluid mainly from magmatic hydrothermal, with mineralization, metallogenic fluid has advanced atmospheric precipitation in the ore-forming fluid with mixed source characteristics and source of ore-forming fluid in MVT lead-zinc deposit basin brine. Indicating the characteristics of sulfur isotope, sulfur in the ore-forming material mainly from magma source. The relative single lead isotope results show that: the Chu lead-zinc deposit lead is mixed lead character, the crust derived lead was mainly mixed with a small amount of deep mantle lead mixing caused by subduction orogenesis and magmatism, mainly from the close relationship between the Cenozoic volcano rock, and ore-forming material sources of sulfur isotope reflect. Comprehensive analysis shows that the Chu multiloop lead-zinc deposit belongs to mesothermal vein type lead-zinc deposit, the relationship between the new generation of large-scale ULTRAPOTASSIUM magmatism mineralization and Tuotuohe area closely controlled by NWW faults, ore controlling structures formed in the Eocene continental collision post orogenic extensional environment.

【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P618.4

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