甘肃西秦岭金矿资源特征及赋矿规律研究

发布时间：2018-09-07 14:08

【摘要】：西秦岭在大地构造位置上是指以宝成铁路为界的秦岭造山带西段,主要分布于甘肃南部境内。甘肃西秦岭地区成矿地质条件优越,金矿资源丰富。自上世纪90年代,区内相继发现了大水、拉尔玛、大桥、李坝、鹿儿坝、李子园、阳山、寨上、早子沟、马泉、加甘滩等一批大型金矿床,其矿床地质特征在我国具有代表性和典型性。本文基于前人关于甘肃西秦岭地区金矿床研究,以矿床学、矿田构造学、矿产资源勘查学、岩石学、地球化学等专业理论为指导,系统统计了研究区190余个金矿床地质特征,通过对早子沟、李坝矿区野外地质调查,综合西秦岭金矿多种成矿信息,对区内金矿资源特征和赋矿规律进行了研究,取得主要认识如下:1、对甘肃西秦岭190余个金矿床地质特征系统总结,发现其空间分布上表现出明显的成带性和集中性,依次可划分为玛曲-碌曲、夏河-合作、迭部-舟曲、礼县-岷县、天水-两当、文县-碧口六个金矿资源集中区。2、结合前人研究及矿床地质特征的总结,按赋矿岩石、矿石特征将区内金矿床划分为构造蚀变岩型、石英脉型、硅质岩型、矽卡岩型、斑岩型、叠加复合型。3、研究区内金矿赋矿岩性是以碎屑岩为主,赋矿地层时代主要集中在泥盆系、三叠系及下古生界等。地层含金性的研究指示,区内金源主要来自于地层而非中酸性岩脉。区内硫源属于壳源沉积硫,δ32S平均值变化大,不均一;大水等金矿C-O同位素特征同样也指示了流体的壳源特征;Pb源在西秦岭金矿成矿系统中基本一致,来自于造山带与下地壳。4、根据在早子沟金矿、李坝金矿区各矿段对矿体的实际详细观察,认为次级小构造、构造裂隙在成矿中起到重要且明显控矿作用。5、通过对甘肃西秦岭地区金矿成矿与构造、地层、岩体之间关系的梳理,归纳了构造、地层、中酸性岩体群等重要控矿因素,提出了西秦岭成矿模式。
[Abstract]:The western Qinling orogenic belt is the western segment of Qinling orogenic belt bounded by Baocheng railway, which is mainly distributed in the southern part of Gansu province. The West Qinling area of Gansu Province has superior metallogenic geological conditions and abundant gold resources. Since the 1990s, a number of large gold deposits have been discovered in the region, such as Dashui, Larma, Bridge, Liba, Luerba, Liziyuan, Yangshan, Zhai Shang, Zaozigou, Ma Quan, Jiagantan, and so on. The geological characteristics of the deposit are representative and typical in China. Based on the previous studies of gold deposits in the West Qinling area of Gansu Province and guided by the theories of ore deposit science, ore field tectonics, mineral resources exploration, petrology and geochemistry, the geological characteristics of more than 190 gold deposits in the study area are systematically counted. Based on the field geological investigation of the Zaizigou and Liba mining areas and synthesizing various metallogenic information of the West Qinling gold deposit, this paper studies the characteristics and the ore-bearing regularity of gold resources in the area. The main conclusions are as follows: 1. The geological characteristics of more than 190 gold deposits in the West Qinling Mountains of Gansu Province have been systematically summarized. It is found that their spatial distribution shows obvious zonation and centrality, which can be divided into Maqu Luqu, Xihe Cooperation and Diego Zhouqu in turn. Lixian-Minxian, Tianshui-Lidang, Wenxian-Bikou six gold resources concentration areas. 2. Combined with previous studies and summary of geological characteristics of ore deposits, gold deposits in this area are divided into structural altered rock type and quartz vein type according to ore-bearing rocks and ore characteristics. Siliceous rock type, skarn type, porphyry type, superimposed compound type. The ore-bearing rocks of gold deposits in the study area are mainly clastic rocks, and the ore-bearing strata are mainly concentrated in Devonian, Triassic and Lower Paleozoic. The study of gold bearing in formation indicates that the gold source in this area mainly comes from strata, not from intermediate-acid veins. Sulfur sources in the area belong to crust-source sedimentary sulfur, 未 32s mean values vary greatly and inhomogeneously, and the C-O isotopic characteristics of gold deposits such as Dashui also indicate that the crust source characteristics of the fluid are basically consistent in the metallogenic system of the West Qinling gold deposit. From the orogenic belt and the lower crust. 4. According to the actual detailed observation of ore bodies in the Zaizigou gold deposit and the Liba gold deposit, it is considered that the secondary small structure, Structural fissures play an important and obvious ore-controlling role in mineralization. By combing the relationship between mineralization and structure, strata and rock mass of gold deposits in West Qinling area, Gansu Province, important ore-controlling factors such as structure, strata, intermediate-acid rock mass group and so on are summarized. The metallogenic model of the West Qinling Mountains is proposed.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P618.51

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