江西弋阳铁砂街铜多金属矿床成因探讨
发布时间：2018-12-11 23:23
【摘要】：铁砂街铜多金属矿床地处萍乡—广丰深断裂南侧,为东西向和北东向构造的交接部位,北武夷成矿带的一部分。赋矿层为中元古界铁砂街岩组,是一套海相变细碧角斑岩系,本文以铁砂街铜矿为研究对象,通过系统采取矿石和围岩样品进行岩石学、岩石地球化学、年代学等研究,以识别该区赋矿岩石类型、围岩蚀变与矿化的关系、岩石成因、成岩成矿年龄以及矿床形成的构造环境等。矿床常发育多种蚀变的叠加,蚀变与矿化在空间和时间上关系密切,其中硅化、绿泥石化、阳起石化、碳酸盐化与矿化关系最为密切。成矿过程大致可划分为3个成矿期5个成矿阶段,即①海底火山喷发、成岩成矿期②变质改造—叠加成矿期(分为氧化物阶段、石英—硫化物阶段和碳酸盐阶段)③表生成矿期。矿区赋矿围岩大部分具有碱性火山岩特征。在TAS图解中的投点较为分散,存在酸性火山岩,也存在基性火山岩,体现为火山喷发不同阶段的产物。其他较分散的点可能是由于后期热液蚀变而成。矿床硫同位素组成具有深源硫的特点;氧同位素组成,反映成矿流体具有以海水为主的岩浆水的混合流体性质,铅同位素组成表明,矿石中铅主要来自于海底火山-沉积地层。据资料,矿区细碧岩锆石SHRIMP年龄1153.4±38.4 Ma;绢云母千枚岩SHRIMP年龄902±23 Ma,与矿化关系密切的钾长石Ar-Ar同位素年龄为138.22±0.64 Ma。表明原始的矿源层喷发于中元古代晚期,大规模的区域变质作用发生在新元古代早期,该矿床至少燕山期又存在一次成矿作用。中元古代晚期,前震旦纪克拉通发生裂谷作用,海底火山活动,成矿物质在海盆中沉淀,形成原始的矿化层;后期加里东期的区域变质作用,变质热液使原始矿化层得到改造;印支期,地壳强烈挤压,对矿体有一定的破坏和再富集的双重作用;燕山期岩浆活动,使矿化层中的成矿元素进一步活化富集成矿。铁砂街岩组形成于后造山阶段板内环境,可能由中元古界华夏陆块减薄开裂导致地幔物质上涌而成。燕山成矿期为太平洋板块俯冲作用而成的造山带。
[Abstract]:The Tieshajie copper polymetallic deposit is located on the south side of Pingxiang-Guangfeng deep fault, which is the junction of east-west and NE trending structures and part of the North Wuyi metallogenic belt. The ore-bearing bed is the Middle Proterozoic Teshajie formation, which is a set of marine fine-grained Bijiao porphyry series. This paper takes Tieshajie Copper Mine as the research object, and systematically studies the petrology, geochemistry and geochronology of the ore and surrounding rock samples. In order to identify the types of ore-bearing rocks, the relationship between the alteration of surrounding rock and mineralization, the genesis of rocks, the age of diagenetic mineralization and the tectonic environment of the deposits, etc. There are many kinds of superposition of alteration in ore deposit. Alteration and mineralization are closely related in space and time, among which silicification, green mud petrifaction, actinization, carbonization and mineralization are the most closely related. The metallogenic process can be roughly divided into three metallogenic periods and five metallogenic stages, I. e., 1 submarine volcanic eruption, 2 metamorphic and superimposed metallogenic stage (divided into oxide stage). Quartz-sulphide stage and carbonate stage). Most of the ore-bearing rocks in the mining area are characterized by alkaline volcanic rocks. The input points in the TAS diagram are scattered, there are acidic volcanic rocks and basic volcanic rocks, which are the products of different stages of volcanic eruption. Other more dispersed points may be due to late hydrothermal alteration. The sulfur isotopic composition of the deposit has the characteristics of deep source sulfur, and the oxygen isotope composition reflects that the ore-forming fluid has the mixed fluid property of magmatic water dominated by seawater. The lead isotope composition shows that the lead in the ore mainly comes from submarine volcanic-sedimentary strata. According to the data, the zircon SHRIMP age of 1153.4 卤38.4 Ma; sericite phyllite SHRIMP age of 902 卤23 Ma, and the Ar-Ar isotopic age of potash feldspar are 138.22 卤0.64 Ma.. It is suggested that the primitive source bed erupted in the late Middle Proterozoic period and the large-scale regional metamorphism occurred in the early Neoproterozoic. At least there was another mineralization in the Yanshanian period of the deposit. In the late Middle Proterozoic period, the pre-Sinian cratonic rift occurred, the submarine volcanic activity, the ore-forming material precipitated in the basin, and formed the primitive mineralized layer, while in the late Caledonian regional metamorphism, the metamorphic hydrothermal fluid transformed the original mineralized layer. During the Indosinian period, the crust was strongly squeezed, and the orebody was destroyed and reenriched to a certain extent, and the Yanshanian magmatic activity further activated and enriched the ore-forming elements in the mineralized bed. The Tieshajie formation was formed in the intraplate environment of the post-orogenic stage and may have been formed by the thinning and cracking of the Mesoproterozoic Cathaysian blocks resulting in the upwelling of mantle material. Yanshanian metallogenic period is a orogenic belt formed by subduction of Pacific plate.
【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】：2015
【分类号】：P618.2
本文编号：2373415
[Abstract]:The Tieshajie copper polymetallic deposit is located on the south side of Pingxiang-Guangfeng deep fault, which is the junction of east-west and NE trending structures and part of the North Wuyi metallogenic belt. The ore-bearing bed is the Middle Proterozoic Teshajie formation, which is a set of marine fine-grained Bijiao porphyry series. This paper takes Tieshajie Copper Mine as the research object, and systematically studies the petrology, geochemistry and geochronology of the ore and surrounding rock samples. In order to identify the types of ore-bearing rocks, the relationship between the alteration of surrounding rock and mineralization, the genesis of rocks, the age of diagenetic mineralization and the tectonic environment of the deposits, etc. There are many kinds of superposition of alteration in ore deposit. Alteration and mineralization are closely related in space and time, among which silicification, green mud petrifaction, actinization, carbonization and mineralization are the most closely related. The metallogenic process can be roughly divided into three metallogenic periods and five metallogenic stages, I. e., 1 submarine volcanic eruption, 2 metamorphic and superimposed metallogenic stage (divided into oxide stage). Quartz-sulphide stage and carbonate stage). Most of the ore-bearing rocks in the mining area are characterized by alkaline volcanic rocks. The input points in the TAS diagram are scattered, there are acidic volcanic rocks and basic volcanic rocks, which are the products of different stages of volcanic eruption. Other more dispersed points may be due to late hydrothermal alteration. The sulfur isotopic composition of the deposit has the characteristics of deep source sulfur, and the oxygen isotope composition reflects that the ore-forming fluid has the mixed fluid property of magmatic water dominated by seawater. The lead isotope composition shows that the lead in the ore mainly comes from submarine volcanic-sedimentary strata. According to the data, the zircon SHRIMP age of 1153.4 卤38.4 Ma; sericite phyllite SHRIMP age of 902 卤23 Ma, and the Ar-Ar isotopic age of potash feldspar are 138.22 卤0.64 Ma.. It is suggested that the primitive source bed erupted in the late Middle Proterozoic period and the large-scale regional metamorphism occurred in the early Neoproterozoic. At least there was another mineralization in the Yanshanian period of the deposit. In the late Middle Proterozoic period, the pre-Sinian cratonic rift occurred, the submarine volcanic activity, the ore-forming material precipitated in the basin, and formed the primitive mineralized layer, while in the late Caledonian regional metamorphism, the metamorphic hydrothermal fluid transformed the original mineralized layer. During the Indosinian period, the crust was strongly squeezed, and the orebody was destroyed and reenriched to a certain extent, and the Yanshanian magmatic activity further activated and enriched the ore-forming elements in the mineralized bed. The Tieshajie formation was formed in the intraplate environment of the post-orogenic stage and may have been formed by the thinning and cracking of the Mesoproterozoic Cathaysian blocks resulting in the upwelling of mantle material. Yanshanian metallogenic period is a orogenic belt formed by subduction of Pacific plate.
【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】：2015
【分类号】：P618.2
【引证文献】
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1 王国龙;;江西铁砂街铜多金属矿田成矿规律及找矿方向[A];加强地质工作 促进可持续发展——2006年华东六省一市地学科技论坛论文集[C];2006年
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