陕西省金堆城斑岩型钼矿床矿物学及地球化学特征

发布时间：2018-04-14 00:10

本文选题：东秦岭 + 花岗斑岩　；参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：金堆城斑岩型钼矿床位于陕西省华县境内,作为超大型钼矿床,引起了国内外许多学者的关注。但是对于金堆城花岗斑岩的成因及形成环境,迄今为止还存在争议;对矿床的矿物学研究还有些不足。本文利用偏光显微、镜电子探针、锆石年代学、LA-ICP-MS等分析方法,对其岩石学、矿物学及岩石地球化学方面进行了详细研究,取得了相关成果,并据此建立了矿床的成岩成矿模式。研究结果如下:1.金堆城花岗斑岩呈肉红色,具斑状结构,斑晶主要为石英、钾长石,粒度在2.5mm~5mm之间;主要造岩矿物为石英、钾长石、钠长石、斜长石、白云母、黑云母;副矿物以磷灰石、磁铁矿、钛铁矿、方解石、锆石、榍石、独居石、磷钇矿等。2.金堆城花岗斑岩具有高硅、高钾、偏铝的特点,属于硅过饱和的超酸性钙碱系列的花岗岩;稀土元素分配曲线为右倾型,具有富集轻稀土、亏损重稀土的特点,其中Eu略微亏损;微量元素具有高场强元素如Th、U、Pb富集的特点,金堆城花岗斑岩的锆石U-Pb年龄为139.44±1.2Ma,表明形成于燕山期。3.本矿床具有蚀变分带的特点,从斑岩体-接触带-围岩依次分为:钾长石化-绢英岩化-硅化-青磐岩化;主要的蚀变矿物包括:钾长石、黑云母、白云母、石英、绿泥石、绿帘石、方解石。4.金堆城斑岩型钼矿床成矿期可分为三期:气成成矿期,热液成矿期,表生成矿期;其中,热液成矿期又分三个阶段:第一阶段发育钾长石-硫化物,第二阶段发育石英-硫化物脉,第三阶段发育石英脉、石英-方解石脉。5.金堆城钼矿床的金属矿物主要包括:磁铁矿、黄铁矿、黄铜矿、辉钼矿、闪锌矿、方铅矿、碲银矿、针硫铋铅矿、含硫铋铅银矿、含铋、银-方铅矿等。6.金堆城花岗斑岩的物质来源主要来自地壳,形成于南北挤压应力向东西拉张应力转化过渡的构造环境。7.金堆城斑岩型钼矿床的成矿温度为中温,成矿物质来源为下地壳并混有少部分的幔源物质。
[Abstract]:Jinduicheng porphyry type molybdenum deposit is located in Huaxian county of Shaanxi Province. As a super large molybdenum deposit, it has attracted the attention of many scholars at home and abroad.However, the origin and formation environment of Jinduicheng granitic porphyry are still controversial up to now, and the mineralogical study of the deposit is still insufficient.In this paper, the petrology, mineralogy and geochemistry of the deposit are studied in detail by means of polarizing microscopy, microprobe, zircon chronology and LA-ICP-MS, and the related results are obtained, and the diagenetic and metallogenic model of the deposit is established accordingly.The results are as follows: 1.Jinduicheng granitic porphyry is flesh-red, porphyry is mainly quartz, potassium feldspar, granularity is between 2.5mm~5mm, the main rock-forming minerals are quartz, potash feldspar, albite, plagioclase, Muscovite, biotite, apatite.Magnetite, ilmenite, calcite, zircon, sphene, monazite, yttrium phosphate, etc.The Jinduicheng granitic porphyry has the characteristics of high silicon, high potassium and partial aluminum, and belongs to the supersaturated supersaturated supersaturated super-acid calcium alkali granite. The distribution curve of rare earth elements is right-tilted, with the characteristics of enrichment of light rare earth elements and depletion of heavy rare earths.The trace elements are characterized by enrichment of high field strength elements such as Thu UZO Pb, and the zircon U-Pb age of the Jinduicheng granitic porphyry is 139.44 卤1.2 Ma, indicating that it was formed in Yanshanian period.The ore deposit has the characteristics of altered zonation, which can be divided into potash feldspar, biotite, biotite, Muscovite, quartz and chlorite from porphyry, contact zone and surrounding rock in turn: potassium feldspar, sericite, sillitization and qiniranlitization, the main altered minerals include: potash feldspar, biotite, Muscovite, quartz, chlorite, etc.Green curtain stone, calcite. 4.The metallogenic period of Jinduicheng porphyry type molybdenum deposit can be divided into three periods: gas metallogenic period, hydrothermal metallogenic stage and epigenetic stage, in which the hydrothermal metallogenic period is divided into three stages: the first stage is potassium feldspar sulfide,Quartz-sulfide veins are developed in the second stage, quartz veins in the third stage, quartz-calcite veins. 5.The metallic minerals of the Jinduicheng molybdenum deposit mainly include magnetite, pyrite, chalcopyrite, molybdenum, sphalerite, galena, tellurite, goeth-bismuth lead ore, sulphobismuth lead silver ore, bismuth containing bismuth, silver-galena, etc.The material source of the Jinduicheng granitic porphyry is mainly from the crust, which is formed in the tectonic environment of the transition from the North to the South compressive stress to the east-west tensile stress.The ore-forming temperature of the Jinduicheng porphyry type molybdenum deposit is medium temperature, and the ore-forming material comes from the lower crust with a small amount of mantle-derived materials.
【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】：P618.65

【相似文献】