【作者】 张海；

【导师】 梅冥相； 方维萱；

【作者基本信息】 中国地质大学（北京） ， 古生物学与地层学， 2010， 博士

【摘要】 云南个旧是一个以锡铜为主的多金属矿区,是环太平洋巨型锡矿带西带的一部分。印支运动中期,个旧及其邻区沉积充填了厚达数千米的碳酸类岩层、碎屑岩和基性-超基性火山岩,并形成了基性火山-沉积型铜多金属矿床。中三叠个旧组以白云岩、灰岩和泥岩为主,属于个旧-那坡弧后裂谷盆地热沉降背景下形成的沉积序列。在个旧组卡房段火山岩中夹有延伸稳定的碳酸盐岩薄层,火山岩与沉积岩交替变更,表现很好的相变关系和岩相序列,是火山岩相研究的良好地区。火山岩相可定义为在一定的环境下一切火山活动产物特征的总称,属于成因相,沉积岩相则采用环境相进行研究,本文是采用成因相和环境相联合方法进行岩相划分。通过对地层、岩性、构造等成矿条件的研究,结合地球化学特征恢复该地区火山岩-沉积岩岩相,总结出岩相、相序、成矿三者之间内在的联系,并取得了如下主要成果:1.中三叠系安尼期个旧组卡房段火山岩原岩为一套碱性基性-超基性岩组合,垂向相序沉积相序表现为爆发相→溢流相→火山沉积相→碳酸盐岩台地相的变化规律,这种相序结构及相组合揭示了火山活动由强到弱,沉积作用不断增强的连续变化过程。垂向相序属于个旧-那坡三叠纪弧后裂谷盆地背景下火山-沉积岩岩相组合类型。2.中三叠安尼期个旧组卡房段火山岩-沉积岩可以划分出3个旋回7个期次,从下部旋回到上部旋回表现出火山活动逐渐减弱的特征。其中下部旋回由3个期次组成,主要岩性以浆屑晶屑角砾凝灰岩为主,岩相主要以爆发相为主。中部旋回由1个期次组成,主要以变余斑状玄武为主,岩相主要以溢流相为主。上部旋回由3个期次组成,主要以金云母角岩和凝灰质大理岩为主,岩相以溢流相和火山沉积相为主。3.盆地流体叠加相、同生构造角砾岩相、夕卡岩相、火山沉积相与溢流相接触带,这四种岩相组合属于本区主要含矿岩相。4、从岩相学角度证明研究区存在印支期海底基性火山沉积成矿作用、印支期海底喷流沉积成矿作用、燕山晚期花岗岩叠加改造多期次成矿作用。更多还原

【Abstract】 Gejiu,Yunnan, tin-copper polymetallic ore deposit is a tin-copper-based multi-metal mining area, which is one of the most tin-rich areas in the western end of West part of Pacific rim giant tin zone. In the middle stage of Indosinian movement, Gejiu and its adjacent areas were back-arc rift basins, filled with thousands of meters thick carbonate rocks, clastic rocks and basic-ultrabasic rocks, and formed the base of volcano-sedimentary copper-polymetallic deposit. Gejiu Formation in Triassic was mainly comprised of dolomite, limestone and mudstone, belonging to the sedimentary sequences of Gejiu-Napo back-arc rift basin under the regime of thermal subsidence. The volcanic rocks of Kafang Member in Gejiu Formation has a carbonate rock thin interbed layer with stable extension, along with meta-volcanic rocks and sedimentary rocks changing in turn, showing a good relation of both phase transition and facies sequence, which is a excellent study case of volcanic facies. Volcanic facies can be defined that it sumsup all the product of volcano movement in certain environment, it is belongs to Causes phase, sedimentary rock should be studyed as per environment, this essay will take reason and environment both tocompartmentalize magma。Via analyzing the mineralization conditions, such as stratigraphy, lithology, structure, etc, combined with geochemical characteristics of volcanic rocks of this area, finally we restore the volcanic-sedimentary facies, and summarize the intrinsically link among lithofacies, phase sequence and mineralization, then we get the main achievements as follows:1. Kafang Member of Gejiu Formation in middle Triassic Anisian, consists of a set of alkaline volcanic protoliths basic - ultrabasic association, and vertical facies sequence shows the variation from the explosive facies to overflow facies, and then carbonate rock platform facies, and this phase sequence and phase composition reveal the increasing deposition process of continuous change of volcanic activity from the strong to weak. Vertical facie sequence belongs to volcanic -sedimentary facies assemblages of Gejiu-Napo back-arc rift basin in Triassic.2. The volcanic - sedimentary rocks of Kafang Member of Gejiu Formaion in middle Triassic Anisian, can be divided into three cycles withseven periods, with the lower cycle back to the top showing a gradual decrease trend of volcanic activity. The lower part of cycle is composed by the three periods, mainly consist of rock crystal chips to pulp chip tuff breccia, and the outbreak facies is the dominated facies; the middle cycle is consist of one period , composed mainly porphyritic basalt,and the overflow facies is the dominated facied; The upper cycle is consist of three periods, mainly composed of phlogopite hornfels and tuffaceous marble, and the overflow facies and with volcanic-sedimentary facies are the dominated facies.3. The contact zones between superimposed basin fluid facies, with the syngenetic structure breccia facies, skarn facies, volcanic sedimentary facies are the main ore-bearing areas.4.From the viewpoint of facieology in this study area, it proves the existence of submarine basic volcanic Indosinian-sedimentary mineralization, mineralization of Indosinian submarine exhalation, and several stages of mineralization superimposed by late Yanshanian granite.更多还原