湖南黄沙坪钨钼多金属矿床地质特征及成矿过程探讨

发布时间：2018-03-19 17:03

本文选题：矽卡岩矿物　切入点：花岗斑岩　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：黄沙坪多金属矿床位于湖南省桂阳县境内,是南岭成矿带上重要的矽卡岩型钨钼多金属矿床。本文对其区域地质、矿床地质、花岗斑岩岩石学特征、岩石地球化学以及矿物学特征等方面进行了系统地研究,并在此基础上进行了成矿过程探讨。研究表明:1.黄沙坪花岗斑岩属于亚碱性花岗岩系列。岩石中轻稀土略富集,Eu负异常明显,轻重稀土分异明显,为右倾型稀土配分模式;微量元素富集U、Pb、Th等高场强元素,岩浆岩属于壳源、A型花岗岩,是板内非造山环境局部伸展-减薄导致地壳重熔的产物。花岗斑岩锆石U-Pb同位素年龄为160.7±1.1Ma,指示黄沙坪花岗斑岩体成岩时代为晚侏罗世,与前人获得的辉钼矿Re-Os等时线年龄153.8±4.8 Ma等成矿年龄对比分析后认为:矽卡岩W、Mo成矿作用与黄沙坪花岗斑岩体成岩作用近同时发生。2.依据矽卡岩产出状态、矿物共生组合和矿石的岩相学特征、金属硫化物种类和成分,将黄沙坪多金属矿床成矿分为矽卡岩期和石英-硫化物期,矽卡岩期又分为早期矽卡岩阶段和退化蚀变阶段,石英-硫化物期又分为早期硫化物阶段和晚期硫化物阶段。3.矽卡岩矿物主要包括石榴石、辉石、符山石、角闪石、绿帘石、绿泥石等,石榴石属于钙铁榴石-钙铝榴石系列,并且由钙铝榴石向钙铁榴石演化;钙铁榴石的震荡环带记录了热液系统中物理化学条件的变化;两类石榴石中普遍含Sn,但钙铁榴石中Sn的含量要明显高于钙铝榴石。辉石为透辉石-钙铁辉石系列,由内接触带向外接触带,辉石中Fe和Mn的含量逐渐升高;角闪石为铁浅闪石和铁韭闪石;矿石矿物主要包括白钨矿、磁铁矿、辉钼矿、辉铋矿、锡石、闪锌矿、方铅矿等;4.矽卡岩矿物组合特征表明,成矿流体至少经历了两次氧化还原性质的转变;辉石中的Mn/Fe值反映了黄沙坪多金属矿床W(Sn)-Mo-Bi→Fe→Zn-Pb的矿化分带及多金属成矿的特点。
[Abstract]:The Huangshaping polymetallic deposit, located in Guiyang County, Hunan Province, is an important skarn type tungsten and molybdenum polymetallic deposit in the Nanling metallogenic belt. Rock geochemistry and mineralogical characteristics have been systematically studied. The ore-forming process of Huangshaping granitic porphyry belongs to the subalkaline granite series. The results show that the ore-forming process of Huangshaping granitic porphyry belongs to the subalkaline granite series. The magmatic rocks belong to the crust-source A-type granite. The zircon U-Pb isotopic age of granitic porphyry is 160.7 卤1.1 Ma, indicating that the Huangshaping granitic porphyry was late Jurassic. Comparing and analyzing the Re-Os isochron age of molybdenum ore obtained by predecessors (153.8 卤4.8 Ma), it is concluded that the mineralization of skarn Wimo and Huangshaping granitic porphyry occurred at the same time. 2. According to the occurrence state of skarn, the metallogenic process of skarn and the diagenesis of Huangshaping granitic porphyry occur at the same time. Mineral symbiotic assemblage and lithofacies characteristics of ores, types and composition of metallic sulphide, the metallogeny of Huangshaping polymetallic deposit is divided into skarn period and quartz-sulfide stage, skarn stage is divided into early skarn stage and degenerative alteration stage. Quartz-sulphide stage is divided into early sulphide stage and late sulphide stage .3.skarn minerals mainly include garnet, pyroxene, amurenite, hornblende, green curtain, chlorite, etc. The change of physical and chemical conditions in the hydrothermal system is recorded in the oscillatory zone of the calcareous garnet, and the change of the physical and chemical conditions in the hydrothermal system is recorded. The contents of Sn in the two kinds of garnet are generally higher than those in the calcium aluminite. The content of Fe and mn in the pyroxene is increased gradually from the inner contact zone to the external contact zone, which is a series of diopside and calciferopyroxene. Hornblende consists of amphibole and leeblende, and ore minerals mainly include scheelite, magnetite, molybdenum, bismuth, cassiterite, sphalerite, galena and so on. The ore-forming fluid underwent at least two redox changes, and the Mn/Fe value in the pyroxene reflected the wnn Sn-Mo-Bi of the Huangshaping polymetallic deposit. 鈫扚e. 鈫扵he characteristics of mineralization zoning and polymetallic mineralization in Zn-Pb.
【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】：2017
【分类号】：P618.2

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