吉林通化二密铜矿成矿地质过程与成矿模式研究

发布时间：2018-06-24 03:29

本文选题：吉林省 + 通化　；参考：《吉林大学》2015年硕士论文

【摘要】：二密铜矿位于吉林省通化市境内，大地构造位置上位于华北地台北缘东段的三源浦火山盆地内，是一个具有悠久开采历史的老矿山。矿区内出露的地层主要为晚侏罗世-白垩纪陆相火山岩-火山碎屑岩地层，局部有太古宙基底和元古宙地层出露；岩浆活动强烈，早白垩世火山作用主要可以分为三个喷发旋回（果松期、林子头期和三棵榆树期），晚期松顶山岩体沿火山通道侵入；矿区构造主要为三源浦复式火山机构，主要为东西向、南北向、北西向和北东向的断裂。矿体主要分布于松顶山岩体的东南部，以及与火山岩地层的内外接触带中，可分为东区、东南区、南区、四道洋岔、四方顶子区及小横道河子等几个矿区，矿体主要以三种形式产出：（1）脉状矿体主要分布在石英闪长岩和花岗斑岩内外接触带中缓倾斜的张性断裂中，自北东向南西，矿带的倾向也从北东向逐渐变为南西向，是该矿区主要的工业矿体；此外，在南部安山岩地层中发育北西向陡倾斜和东西的缓倾斜的细脉浸染状矿体；（2）浸染状矿体主要分布在花岗斑岩和石英闪长岩体内；（3）在花岗斑岩体顶部的角砾岩内发育块状的富矿体以及水晶矿产；矿石矿物主要为毒砂、磁黄铁矿、黄铜矿和黄铁矿等，其次为辉钼矿、闪锌矿等；脉石矿物主要由石英、绢云母、绿泥石、方解石等组成；围岩蚀变主要为硅化、绢云母化、青磐岩化、碳酸盐化和高岭土化等。二密铜矿的成矿作用与松顶山岩体密切相关，岩体的主体岩性为石英闪长岩、石英二长闪长岩、花岗闪长岩、斑状花岗闪长岩和花岗斑岩等。LA-ICP-MS锆石U-Pb精确测年获得花岗闪长岩、石英闪长岩和斑状花岗闪长岩的结晶年龄分别为94.2±1.7Ma（N=15，MSWD=0.53）、94.3±1.2Ma（N=17，MSWD=0.30）和93.9±1.2Ma（N=19，MSWD=0.22）。元素地球化学特征显示，松顶山岩体为中酸性侵入岩，SiO2=56.76~72.69%， Na2O=3.64~6.44%， K2O=1.88~3.87%， CaO=1.86~6.41%，A/CNK=0.86~0.97，A/NK=1.29~2.05，属于亚碱性高钾钙碱性系列，具有低的Mg#（0.28~0.38）；稀土元素配分图解呈右倾斜模式（LREE/HREE=5.75~9.84;（La/Yb）N=5.27~10.36），δEu=0.71~1.12；微量元素以富集Rb、Ba、Th、U、K和LREE等大离子亲石元素（LILEs）和亏损Nb、Ta、P、Ti和HREE等高场强元素（HFSEs）为特征；（87Sr/86Sr）i比值和εNd（t）值分别为0.70765~0.70829和-13.8~-10.8，Nd模式年龄TDM为1.68~2..05Ga，与该区早白垩世火山岩Sr-Nd同位素比值相似，表明它们的源区由太古宙下地壳和底侵的玄武岩两个端元组成，原始岩浆起源于受板块流体交代的地幔楔。结合前人的研究，本文认为二密铜矿的成岩成矿作用发生在晚白垩世，形成于太平洋俯冲作用背景下的伸展环境下。矿床地质特征、室内矿相学研究表明成矿过程包括石英-黄铁矿阶段、石英-辉钼矿-黄铁矿-黄铜矿阶段、石英-黄铜矿-多金属成矿阶段、灰白色石英-绿泥石化-黄铁矿-块状黄铜矿阶段、石英-碳酸盐阶段五个阶段。流体包裹体研究表明流体包裹体类型主要为富液相包裹体和含子晶三相包裹体，还含有少量富气相包裹体；流体包裹体的均一温度为149.9~450℃，盐度为3.85~52.42wt%，可划分为445~450℃、330.5~419℃、260~328.9℃、204~258.4℃和149.9~180.3℃五个阶段；其中，富液相包裹体均一温度为149.9~450℃，盐度为3.85~12.65，密度为0.584~0.970g/cm3；含子晶三相包裹体均一温度为265~419℃，，盐度为34.72~38.57wt%，密度为1.107~1.110g/cm3；富气相包裹体均一温度为358~362℃，盐度为3.85~9.65wt%，密度为0.63~0.72g/cm3。激光拉曼成分分析显示，富液相体包裹体成分主要为H2O和CH4，含子晶三相包裹体成分主要为H2O，富气相包裹体成分主要为CO2和CH4；流体沸腾和温度降低是二密铜矿重要的成矿机制。
[Abstract]:The two dense copper mine is located in the Tonghua city of Jilin province. The tectonic position is located in the Sanyuan basin volcanic basin in the eastern part of the Taipei edge of North China. It is an old mine with a long history of mining. The exposed strata in the mining area are mainly late Jurassic Cretaceous volcanic clastic rocks in the Cretaceous and volcanic clastic rocks, and some Archean basement and Proterozoic era. The volcanic activity of the early Cretaceous can be divided into three eruptive cycles (fruit pine period, forest head stage and three elm period), and the late pine roof rock mass is intruded along the volcanic passage, and the main structure of the mining area is the Sanyuan PU compound volcano, which is mainly east west, North and south, northwestern and northward.
The ore bodies are mainly distributed in the southeastern part of the pantinshan rock mass and in the inner and outer contact zones of the volcanic rocks, which can be divided into eastern, Southeast, southern, four Dao Yang, Sifang and Xiao Heng River, and the ore bodies are mainly produced in three forms: (1) the veins are mainly distributed inside and outside the quartz diorite and granite porphyry. In the gently inclined tensional fracture of the belt, the tendency of the ore belt from the North East to the South West, and from the North East to the South West, is the main industrial ore body in the mining area. In addition, in the southern andesite, the North West to steeply inclined and gently inclined fine vein disseminated orebodies are developed, and (2) the disseminated orebodies are mainly distributed in granite porphyry and stone. (3) the massive ore bodies and crystal minerals are developed in the breccia at the top of the granitoid rock mass; ore minerals are mainly arsenopyrite, pyrrhotite, chalcopyrite and pyrite, followed by molybdenite, sphalerite, etc.; the gangue minerals are mainly composed of quartz, sericite, chlorite, calcite, etc.; the alteration of the surrounding rock is mainly caused by the alteration of the surrounding rock. Silicification, sericite, dolomitization, carbonation and KAOLINIZATION.
The mineralization of the two dense copper mine is closely related to the pinzidan rock mass. The main lithology of the rock mass is quartz diorite, quartz two diorite, granodiorite, porphyritic granodiorite and granite porphyry to obtain granodiorite, and the crystalline age of quartz diorite and porphyritic diorite is 94.2 + 1, respectively, with.LA-ICP-MS zircon. .7Ma (N=15, MSWD=0.53), 94.3 + 1.2Ma (N=17, MSWD=0.30) and 93.9 + 1.2Ma (N=19, MSWD=0.22). The elemental geochemical characteristics show that the pine roof rock is a medium acid intrusive rock, SiO2=56.76~72.69%, Na2O=3.64~6.44%, K2O=1.88~3.87%, and belongs to the subalkaline high potassium calc alkaline series with low (0) .28~0.38); the distribution of rare earth elements is in the right tilt mode (LREE/HREE=5.75~9.84; (La/Yb) N=5.27~10.36) and delta Eu=0.71~1.12, and the trace elements are characterized by the enrichment of large ionic stone elements such as Rb, Ba, Th, U, K and LREE. The 829 and -13.8~-10.8, Nd mode age TDM is 1.68~2..05Ga, similar to the Sr-Nd isotope ratio of the early Cretaceous volcanic rocks in this area, indicating that their source region is composed of two endpoints of the Archean Lower Crust and the basalt in the bottom, and the original magma originated from the mantle wedge with the metasomatism of the plate fluid. Rock mineralization occurred in the late Cretaceous, and was formed in the extensional environment of Pacific subduction.
The geological characteristics of the deposit and the study of indoor mineralogy indicate that the mineralization process includes quartz - pyrite stage, quartz - molybdenite - pyrite - chalcopyrite stage, quartz - chalcopyrite - polymetallic phase, gray - white quartz - greenstone - pyrite - block chalcopyrite stage and five stages of quartz - carbonate phase. Fluid inclusion studies show that fluid The inclusions are mainly rich liquid inclusions and three phase inclusions containing seed crystals, and contain a small amount of rich gas inclusions. The homogenization temperature of the fluid inclusions is 149.9~450 C, and the salinity is 3.85~52.42wt%, which can be divided into five stages, 445~450, 330.5~419, 260~328.9, 204~258.4 and 149.9~180.3; among them, the rich liquid inclusions are homogeneous. The temperature is 149.9~450 C, the salinity is 3.85~12.65, the density is 0.584~0.970g/cm3, the homogeneous temperature of the three phase inclusions is 265~419 C, the salinity is 34.72~38.57wt%, the density is 1.107~1.110g/cm3, the homogeneous temperature of the rich gas phase inclusions is 358~362 C, the salinity is 3.85~9.65wt%, the density of the 0.63~0.72g/cm3. laser Raman analysis shows that the rich liquid is rich. The main components of the phase inclusions are H2O and CH4, and the composition of the three phase inclusions is mainly H2O, and the composition of the rich gas inclusions is mainly CO2 and CH4, and the fluid boiling and the temperature decrease are the important metallogenic mechanism of the two dense copper deposit.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.41

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