新疆库鲁克塔格大金沟金矿地质特征及成矿机制研究

发布时间：2018-06-30 08:22

本文选题：造山型金矿 + 流体包裹体　；参考：《南京大学》2015年硕士论文

【摘要】：库鲁克塔格位于塔里木东北缘,是塔里木克拉通前寒武系出露最为广泛的地区。前人对该古老陆块之内金矿床的类型及与前寒武纪地质作用的关系十分关注,然而由于该区自然条件恶劣,交通极为不便,导致该区的地质研究程度较低,矿床的地质特征及成因类型也不明确,更无针对成矿流体的专题研究。大金沟金矿是塔北缘库鲁克塔格前寒武纪地块上较为重要的金矿床。该矿床所有矿体均赋存于红柳构群小金沟组条带状(石榴)混合片麻岩中,受构造破碎带控制。通过对该矿床不同期次(成矿前、主成矿期和成矿期后)石英脉中流体包裹体岩相学观察和显微测温工作,发现该矿床整个流体演化过程中温度略呈逐渐降低趋势,属典型的中低盐度流体体系(2.6～15.5% wt%NaCl),与造山过程相关的变质流体类似(3～10% wt%NaCl)。该矿床含金石英脉的氢氧同位素分析结果表明大金沟成矿流体主体为来自深部变质岩的变质水与少量天水的混合,而成矿期后石英脉中热液锆石的U-Pb年龄(795±20Ma)与矿体内云英岩中绢云母的Ar-Ar年龄(等时线年龄833.3±7.9,坪年龄为829.4±4.8Ma)均指示成矿时间与新元古代中晚期塔里木北缘广泛发育的聚合事件时间相一致。综合大金沟金矿的矿床地质特征、流体包裹体、氢氧同位素及成矿年代学结果,初步认为大金沟金矿是新元古代中期(-830Ma),库鲁克塔格在超大陆聚合背景之下形成的造山型金矿床。
[Abstract]:Kuruktag, located on the northeast edge of Tarim, is the most widely exposed area of the Precambrian in the Tarim craton. The former people paid great attention to the type of gold deposit in the ancient continental block and its relationship with the Precambrian geological process. However, due to the poor natural conditions and the extremely inconvenient transportation in the area, the degree of geological research in the area is relatively low. The geological characteristics and genetic types of ore deposits are also unclear, and there is no special study on ore-forming fluids. The Daginggou gold deposit is an important gold deposit in the Precambrian block of Kuluktagh, northern Tata. All orebodies of the deposit are located in the zonal (pomegranate) mixed gneiss of the Xiaojingou formation of the Hongliuku Group, which is controlled by the structural fracture zone. Based on the petrographic observation and microthermometry of fluid inclusions in quartz veins before, during and after mineralization, it is found that the temperature of fluid inclusions in the deposit decreases slightly during the whole fluid evolution process of the deposit. It is a typical medium and low salinity fluid system (2.6U 15.5wt% WTI NaCl), and the metamorphic fluid associated with orogenic process is similar (310wt% WTI NaCl). The results of hydrogen and oxygen isotopic analysis of gold bearing quartz veins in the deposit indicate that the ore-forming fluid in Daginggou is mainly composed of metamorphic water from deep metamorphic rocks and a small amount of Tianshui. The U-Pb age of hydrothermal zircon in quartz vein after mineralization (795 卤20Ma) and the Ar-Ar age of sericite (833.3 卤7.9 Ma, plateau age 829.4 卤4.8 Ma) in the magnetite indicate that the metallogenic age is related to the extensive development of the northern margin of Tarim in the middle and late Neoproterozoic. The time of the aggregation event is the same. Based on the ore deposit geological characteristics, fluid inclusions, hydrogen and oxygen isotopes and metallogenic geochronology of the Daginggou gold deposit, it is preliminarily considered that the Daginggou gold deposit is an orogenic gold deposit formed in the middle Neoproterozoic period (-830Ma) and in the supercontinental aggregation setting.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.51

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