滇东北茂租热液型铅锌矿床矿物组合共生分异的热力学Eh—pH相图

发布时间：2018-03-07 12:34

本文选题：热液型铅锌矿床　切入点：成矿流体　出处：《地质论评》2017年05期 　论文类型：期刊论文

【摘要】：滇东北地区广泛分布的热液型铅锌矿床具有普遍的矿物组合分带特征,研究矿床矿物组合的共生分异特征,是了解该类型矿床的成矿流体在演化过程中,成矿元素迁移和沉淀的核心问题之一,通过共生矿物的热力学Eh—pH相图可以有效的诠释成矿流体中成矿元素在迁移、沉淀过程中的物理化学条件。本文以滇东北茂租铅锌矿床为例,对滇东北热液型铅锌矿床的金属矿物共生组合在时间、空间分带特征进行热力学相图分析,选取373K、423K、473K、523K四个温度截面对金属矿物共生组合稳定存在的Eh—pH范围进行计算,相图显示成矿流体中矿物迁移、沉淀机制主要是由于成矿流体的Eh、p H值双重制约:Eh值的变化控制着硫化物沉淀的时间分带,成矿流体从深部向浅部运移,Eh值将会逐渐增大,主要矿物从黄铁矿→方铅矿→闪锌矿依次开始析出;p H值控制硫化物的空间分带,随着p H值的增大,成矿元素从离子的形式转变为硫酸盐矿物进行迁移。研究表明,控制成矿流体中硫化物迁移、沉淀的物理化学条件除了温度、压力、金属离子浓度及流体的氧硫逸度之外,流体的酸碱度及氧化还原电位同样是控制矿物组合共生分异的重要影响因素,此研究对该类型矿床的成矿流体的演化和成矿机制提供了一定的理论依据。
[Abstract]:The widely distributed hydrothermal lead-zinc deposits in northeast Yunnan have the characteristics of general mineral assemblage and zonation. To study the symbiotic differentiation characteristics of mineral assemblages of the deposits is to understand the metallogenic fluids of the deposits in the course of evolution. One of the core problems of the migration and precipitation of metallogenic elements is that the migration of metallogenic elements in the ore-forming fluid can be effectively interpreted by the thermodynamic Eh-pH phase diagram of the symbiotic minerals. Physical and chemical conditions in the process of precipitation. In this paper, a thermodynamic phase diagram analysis of the time and space zonation characteristics of the metal-mineral symbiotic assemblage of the hydrothermal lead-zinc deposit in northeastern Yunnan is carried out, taking the Maussuo Pb-Zn deposit in northeastern Yunnan as an example. The stable Eh-pH range of the metal mineral symbiotic assemblage is calculated with four temperature sections of 373K ~ 423K ~ 473K ~ 523K. The phase diagram shows the mineral migration in the ore-forming fluid. The precipitation mechanism is mainly due to the double restriction of EhPH value of ore-forming fluid, the change of Eh value to control the time zoning of sulfide precipitation, the migration of ore-forming fluid from deep to shallow will gradually increase the Eh value, and the main mineral is pyrite. 鈫扜alena. 鈫扴phalerite began to precipitate in turn to control the spatial zonation of sulphide. With the increase of pH value, the ore-forming elements changed from ion form to sulfate mineral for migration. In addition to temperature, pressure, concentration of metal ions and oxygen sulfur fugacity of fluids, the pH and redox potential of fluids are also important factors controlling the symbiotic differentiation of mineral assemblages. This study provides a theoretical basis for the evolution and metallogenic mechanism of ore-forming fluids in this type of deposit.
【作者单位】：中南大学地球科学与信息物理学院;中南大学有色金属成矿预测教育部重点实验室;中国地震局地质研究所;云南省有色地质局地质地球物理化学勘查院;
【基金】：国家自然科学基金资助项目(批准号:41272096,41462003) 国土资源部公益性行业科研专项课题(编号:200911007) 云南省地质勘查基金资助项目(编号:201000042、20100004)的成果~~
【分类号】：P618.4

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