青海祁漫塔格地区它温查汉西铁多金属矿床地质特征及成因探讨

发布时间：2018-06-13 14:23

本文选题：矿床成因 + 它温查汉西　；参考：《长安大学》2015年硕士论文

【摘要】：它温查汉西铁多金属矿床位于青海祁漫塔格山东南部,距离格尔木市西北(300°方位)约200km,是近年来继沙丘、长山、牛苦头后在该地区发现的又一中型铁多金属矿床,铁矿石探明资源量超过4000万吨,其矿体与成矿岩体均隐伏于第四系风积砂覆盖层下。矿区的大地构造位置位于东昆北祁漫塔格早古生代岩浆弧带,在那陵格勒河断裂的北侧。地理坐标为:东经92°31′-92°52′,北纬36°55′-37°00′之间,总面积约100km2。本论文通过研究它温查汉西铁多金属矿床的地质特征、蚀变分带性以及成矿岩体的地球化学特征,以期查明该矿床地质成因、成矿期次、控矿要素和找矿模式,并与其他矿床进行对比,确立区域上的主攻矿床类型和总结成矿规律,从而有效指导矿产勘查实践。最终,关于祁漫塔格地区构造-岩浆-成矿的关系,以及它温查汉西铁多金属矿床的地质特征及成因,取得了如下研究成果:(1)梳理出东昆仑西段(祁漫塔格地区)在中三叠世早期约(242~239Ma)正处于洋壳俯冲结束向碰撞开始的转换阶段,而从237~204Ma区内转入后碰撞伸展阶段。期间发生过大规模的幔源岩浆底侵和壳幔混合作用,尤以中-晚三叠世(210~237Ma)的花岗岩最为发育,与成矿关系最为密切。(2)测得矿区钻孔ZK25408中的花岗闪长岩的LA-ICP-MS锆石U-Pb年龄为(236.1±1.2)Ma,属于中三叠世(T2),代表了岩浆的结晶年龄,与前人对磁铁矿中白云母利用40Ar-39Ar法获得(230.7±2.0Ma)的坪年龄和(229.9±3.5Ma)的等时线年龄一致,印证了岩浆作用对成矿的贡献。(3)查明矿区花岗闪长斑岩属于弱过铝质、高钾钙碱性花岗岩,其成因类型为I型花岗岩,具有LILE(如Ba、Sr等)相对亏损和HFSE(如Th、U、Zr、Hf等)相对富集的特征;稀土元素配分曲线呈右倾型,斜率较大,具有相对富LREE、贫HREE以及负Eu异常的特征。(4)三叠纪中-晚期对应区内最后一个构造-岩浆-成矿旋回,是祁漫塔格地区后期的主要成矿期。NWW向区域性深大断裂控制了主要侵入岩体和矿集区的分布,次级断裂蚀变带赋存有重要矿床(体)。它温查汉西多金属矿床是典型的受断层和岩浆作用共同控制的与岩浆-热液系统有关的铁矿类型,兼具矽卡岩型矿床和热液脉型矿床的特征。(5)它温查汉西铁多金属矿床的形成经历了矽卡岩期和石英-硫化物期。其中,矽卡岩期又细分为早(干)矽卡岩阶段、晚(湿)矽卡岩阶段以及退化蚀变阶段;石英-硫化物期又细分为早硫化物阶段(铁-铜硫化物阶段)和晚硫化物阶段(铅-锌硫化物阶段)。(6)矿石结构构造、矿物组合以及围岩蚀变的特征,显示矿床成矿温度和元素具有分带性:在接触带附近按距离侵入体中心由近到远SiO2和Fe2O3、Al2O3含量由高逐渐降低,CaO含量则由低逐渐升高;在内接触带主要由较高温矿物组成;在外接触带主要由高-中温矿物组成。(7)归纳推测它温查汉西铁多金属矿床矿石中稀土元素配分与成矿花岗闪长斑岩应该具有相同的特征,二者系同一岩浆作用在不同阶段的产物;硫、铅的主要来源为幔源岩浆,伴有不同程度的壳源物质的混入。
[Abstract]:It is located in the southern part of Shandong of qiminutan, Qinghai, located in the northwest of Golmud city (300 degrees). It is another medium-sized iron polymetallic deposit found in this area in recent years after the bitter head of the sand dunes, Changshan and cattle. The ore exploration resources are more than 40 million tons, and the ore body and the ore-forming rock are hidden in the Quaternary wind. Under the sand cover layer, the geotectonic position of the mining area is located in the early Paleozoic magmatic arc zone of the East Kunlun Qun TGGE, and on the north side of the fault of the mausoleum river. The geographical coordinates are: the East Jing 92 degree 31 '-92 degree 52', the northern latitude 36 degrees 55 '-37 degree 00', the total area about 100km2.. The variation zone and the geochemical characteristics of the ore-forming rock masses are expected to find out the geological genesis of the ore deposit, the metallogenic epoch, the ore controlling elements and the ore prospecting model, and compare with the other ore deposits, establish the main types of ore deposits in the region and summarize the metallogenic regularity, and thus effectively guide the mineral exploration practice. The relationship of mineralization and the geological characteristics and causes of its west iron polymetallic deposit have been obtained as follows: (1) combing the western part of the East Kunlun (Qun Tai Ge region) in the early middle three fold period (242~239Ma) is in the transition phase of the end of the oceanic subduction to the beginning of the collision, and from the 237~204Ma region to the post collision extension stage. Large scale mantle derived magma undertransgression and crust mantle mixing occurred during the period, especially in the middle late three fold (210~237Ma) granites, which were most closely related to mineralization. (2) the LA-ICP-MS zircon U-Pb age of granodiorite in the drilling ZK25408 of the mining area was (236.1 + 1.2) Ma, belonging to the middle three world (T2), representing the year of crystallization of the magma. Age, consistent with the age of 40Ar-39Ar (230.7 + 2.0Ma) and (229.9 + 3.5Ma) isochronous age of (229.9 + 3.5Ma) of the Muscovite in magnetite, the contribution of magmatism to mineralization is confirmed. (3) it is found that the granite diorite porphyry in the mining area belongs to the weak peralalic and high potassium calc alkaline granite, and its genetic type is I type granite, which has LILE (such as Ba, Sr). Relative enrichment characteristics of relative loss and HFSE (such as Th, U, Zr, Hf, etc.); the distribution curves of rare earth elements are right-shaped, with a larger slope, relatively rich in LREE, poor HREE and negative Eu anomalies. (4) the last tectonic magma mineralization cycle in the middle and Late Triassic period is the.NWW direction region of the main metallogenic period in the late qunantag region. The sexual deep fault control the distribution of the main intrusive rock mass and ore area, the secondary fracture alteration zone has an important deposit (body). It is a typical type of iron ore related to the magmatic hydrothermal system controlled by faults and magmatism, and has the characteristics of the skarn deposit and hydrothermal vein type deposit. (5) it The formation of the west iron polymetallic deposit experienced skarn and quartz sulfide periods, among which the skarn period was subdivided into early (dry) skarn phase, late (wet) skarn phase and degenerate alteration stage, and quartz sulfide phase was subdivided into early sulfide phase (iron copper sulfide phase) and late sulfide phase (lead zinc sulfide). (6) (6) the characteristics of ore structure, mineral assemblage and wall rock alteration show that the metallogenic temperature and elements of the ore deposit are Zoning: near to the center of the contact zone, the content of Al2O3 is gradually reduced from high to Fe2O3, the content of Al2O3 is gradually reduced, and the content of CaO is gradually rising from low to high; The contact zone is mainly composed of high medium temperature minerals. (7) it is concluded that the distribution of rare earth elements in the ore of the west iron polymetallic deposit should have the same characteristics as the metallogenic granite diorite porphyry, and the two is the product of the same magmatism at different stages; the main source of sulfur and lead is the mantle derived magma, accompanied by different degrees of shell source. Mix in.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.2

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