CAJ | 학술논문

会泽型铅锌矿床是川-滇-黔接壤区广泛分布的直接受冲断褶皱构造控制的铅锌矿床，其突出特点之一是矿体中矿物组合具有明显的分带性，其形成机理研究是探究构造驱动成矿流体演化过程的关键科学问题之一。本文通过精细解剖典型的云南昭通铅锌矿床，以岩矿鉴定和矿物流体包裹体研究为基础，建立了相关热液体系中多组分平衡关系，构建了铅、锌、铁及其氧化物和硫化物的logfo2-logfs2相图。根据计算结果和相图讨论了形成不同矿物及其组合的流体迁移、沉淀的氧硫逸度条件和金属矿物分带机理。以473 K相图为例，解析了16种矿物及其组合稳定存在的logfo2、logfs2范围及特征，揭示了氧-硫逸度是铅锌元素共生分异的主要原因，并直接控制了矿物组合分带。研究表明，随着成矿流体的演化，温度下降，矿物沉淀所需的fo2、fs2随之减小，氧化还原作用趋弱。理论计算和相图与宏观、微观地质事实相符。
회택형연자광상시천-전-검접양구엄범분포적직접수충단습추구조공제적연자광상，기돌출특점지일시광체중광물조합구유명현적분대성，기형성궤리연구시탐구구조구동성광류체연화과정적관건과학문제지일。본문통과정세해부전형적운남소통연자광상，이암광감정화광물류체포과체연구위기출，건립료상관열액체계중다조분평형관계，구건료연、자、철급기양화물화류화물적logfo2-logfs2상도。근거계산결과화상도토론료형성불동광물급기조합적류체천이、침정적양류일도조건화금속광물분대궤리。이473 K상도위례，해석료16충광물급기조합은정존재적logfo2、logfs2범위급특정，게시료양-류일도시연자원소공생분이적주요원인，병직접공제료광물조합분대。연구표명，수착성광류체적연화，온도하강，광물침정소수적fo2、fs2수지감소，양화환원작용추약。이론계산화상도여굉관、미관지질사실상부。
The Huize-type Pb-Zn deposits in Northeast Yunnan, located in the north side of the Sichuan- Yunnan-Guizhou lead-zinc polymetallic mineralization domain and tectonically on the southwestern margin of the Yangtze block, are controlled by thrust-fold structures directly. The Zhaotong large-size Pb-Zn deposit is one of the representatives of these deposits. The major minerals of the Huize-type lead-zinc deposits are commonly characterized by zonation, i.e., coarse-grained pyrite+a little puce sphalerite→brown sphalerite+galena+ferrodolomite→galena+sandy beige and faint yellow sphalerite+quartz+calcite→ fine-grained pyrite+dolomite+calcite from the floor to the roof of the ore bodies. The ore-forming mechanism of the pattern is one of the key scientific issues in the study of the evolution process of the ore-forming fluid driven by structure. This paper, demonstrating the Zhaotong Pb-Zn deposit as a case study, has studied the controlling mechanism of oxygen-sulfur fugacity for the main metal sulfide assemblages and mineral zoning. It will contribute to understand the forming mechanism of paragenesis and separation of lead and zinc. logfo2-logfs2 phase diagrams for the lead, zinc, iron sulfides and oxides under equilibrium in the relevant hydrothermal system have been re-constructed on the basis of the test results of fluid inclusions and the results of rock and ore appraisal. The calculated results and the phase diagrams indicated that thefo2andfs2 conditions of the transport and precipitation in which the various kinds of minerals and their assemblages formed, and the processes and mechanism of the metallic mineral zoning have been discussed. Taking the 473 K phase diagram as example, the stable logfo2-logfs2 ranges of the 16 kinds of minerals and their assemblages and the block distribution are analyzed. It is shown that metallic mineral zoning and the lead-zinc paragenesis and separation of the deposit was resulted from the variation of fo2andfs2. With the decrease of the temperature, the values offo2andfs2required for mineral precipitation also decreased. The results of the theoretic calculation and the phase diagrams are consistent with both macro-geological and micro-geological characteristics of the lead-zinc mineralization.