【作者】 冯娟萍；

【导师】 王居里；

【作者基本信息】 西北大学 ， 矿物学、岩石学、矿床学， 2005， 硕士

【摘要】 与陆相火山岩有关的浅成低温热液型金矿床虽然经过近代一百多年的研究,但对其认识仍处于一个不断深化的阶段。特别是20世纪80年代以来,随着一系列本类型金矿床在世界范围内被不断发现,对其特征及成因的研究便越来越深入。迄今为止,对不同成矿域中本类型金矿床的深入研究,在现代成矿学研究中仍占有重要地位。 新疆伊宁县吐拉苏盆地内产有众多与陆相火山岩有关的浅成低温热液型金矿床(点),代表性的有阿希大型、京希和伊尔曼得中—小型金矿床,这些金矿床自发现以来,不少研究者陆续对其进行了研究。就目前存在的主要问题来看,争议的焦点仍在于对成矿流体来源的认识上,对成矿流体来源认识的不同必然导致在成矿作用过程及形成机制的认识上存在分歧。 本研究针对这些长期存在的争议问题,以“十五”国家科技攻关计划“吐拉苏金矿带大型金矿床定位预测”专题为依托,从地质、地球化学及流体包裹体等多角度研究入手,对阿希、京希和伊尔曼得金矿床的特征、成矿流体来源、成矿作用过程及成因类型进行了较为系统的研究,取得了以下新认识: 1.明确了成矿流体、成矿物质的来源。本文结合流体包裹体与地球化学研究对成矿流体、成矿物质的来源进行了探讨。首次采用激光拉曼光谱对单个流体包裹体的成分进行了分析,并采用流体包裹体显微测温方法对成矿流体的温度、压力等物理化学参数进行测定与估算,同时对具有代表性的岩石与矿石进行了常量、微量、稀土元素及同位素分析,认为成矿流体来源于早石炭世岩浆作用所产生的火山—次火山热液,晚期有大气降水参与;成矿物质主要来源于下石炭统大哈拉军山组中、中酸性火山岩及火山碎屑岩。 2.本次研究进一步确定了区内次火山岩体与成矿的密切关系。对这三个金矿区内出露的次火山岩体进行了进一步的研究,确定了其不仅是成矿流体、物质的来源之一,而且更重要的是,它是成矿过程中的热动力来源。 3.确定阿希、京希和伊尔曼得金矿床为相同的矿化类型。通过对岩石、矿石的矿物组成、组构等资料综合分析研究,对阿希、京希与伊尔曼得金矿床赋矿层位及其矿化类型进行了探讨,认为阿希、京希与伊尔曼得金矿床所赋存的下石炭统大哈拉军山组为有利的赋矿地层,金矿的形成与强烈的次生石英岩化关系极为密切,发生了次生石英岩型矿化。 4.首次提出区内金矿床具有三位一体控矿特征的新认识。综合野外及室内研究,提出区内金成矿作用的发生具有层位(下石炭统大哈拉军山组)、蚀变(强烈的次生石英岩化)及构造(破火山口以及构造天山构造与非天山构造的交汇部更多还原

【Abstract】 Although the study on epithermal gold deposits related to volcanic rocks has been continuing for about 100 years, it is still the stage that our cognitions for them have been deepening gradually. Especially from the 1980’s on, with a series of this type gold deposits were discovered, the studies on their characters and the cause of formation have being more and more further. So far, researches of this type gold deposit in the different metallogenic provinces have become one of the key fields in modern ore-forming geology.There are many epithermal gold deposits related to subaerial volcanic rocks in Tulasu basin of Yining county, Xinjiang where have Axi, Jingxi and Yelmend represented large and mid-small gold deposits, respectively, which had been researched by many researchers in succession since they were discovered. At present, as for chief problems, the focus of disputation is yet the origin of metallogenic liquid, which brings on bifurcation necessarily for the process and mechanism of mineralization.This study is supported by the subject that is the tenth five-year national plan of tackling science and technology key problems of orientation and forecast of large gold deposits in Tulasu gold belt, and in allusion to those long-standing disputed issues, the much systemic researches on the characteristics, source of metallogenic liquid, process and style of mineralization have been carried out by means of geology, geochemistry and fluid inclusions. So these points of view are put forward thereinafter.1. Combined studying fluid inclusions with geochemistry, the source of fluid and matter of mineralization are made clear in this research. The homogenization temperatures, salinities, pressures, and etc. were mensurated. Moreover, components of these single fluid inclusions in samples were analyzed with a LRM for the first time. And the oxide, trace, REE elements and isotopes of representative rocks and ores in main gold deposits were analyzed. Based on above data, it is considered that the ore-forming fluid is major volcanic-subvolcanic hydrothermal fluid mixed minor meteoric water later. And the material mineralization derives from the intermediate to intermediate-acid volcanic rocks and pyroclastics of the Lower Carboniferous Dahalajunshan Formation.2. By further studying the subvolcanic rocks in mining area, the closerelationship between metallogenism and volcanism is confirmed, that the ore-forming fluid and material were offered by the volcanism, what’s more, the heat and dynamics were supplied by it.3. It is defined that Axi, Jingxi and Yelmend gold deposits are the same Au-mineralizing style. By comprehensive analysis the data of the minerals, texture and structure of ores and rocks, the host rocks and the style of mineralization in Axi, Jingxi and Yelmend gold deposits are discussed, and it is suggested that the Lower Carboniferous Dahalajunshan Formation hosted the three gold deposits is advantaged ore-bearing strata and the metallization is related to intense silicification, resulted of forming auriferous secondary quartzite which is one of important ore types of them.4. For the first time, the new idea is put forward that the distribution of ores have the trinity character. Synthesizing the data of field and interior, it is thought that the occurring of metallogeniam lies on strata (the Lower Carboniferous Dahalajunshan Formation), alteration (intense silicification) and structures (calderas, Tianshan structures and anti-Tianshan structures), which will play an important role in guiding exploration and prospecting.Furthermore, there is a quantity of organic compounds such as CH4, C2H4, C6H6, C4H6 and so on in those fluid inclusions. So it is inferred these organic compounds be likely to have a part in ore forming, but the advanced researches have not yet carried out because of limitation in the studying conditions.更多还原