安徽青阳地区钨钼成矿作用研究

发布时间：2018-03-12 22:22

本文选题：皖南　切入点：青阳　出处：《合肥工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：本文依托中国地质调查局项目《长江中下游成矿带中段深部地质调查》,在系统收集和全面了解区域地质背景的基础上,选择区内典型的青阳-九华山复式岩体及其北部的高家X]、百丈岩钨钼矿床为研究对象。通过野外地质调查及室内综合鉴定,结合岩石地球化学分析、锆石U-Pb同位素定年、辉钼矿Re-Os定年、矿物电子探针等方法,探讨青阳-九华山复式岩体的形成过程,解析钨钼矿床的成矿机制。取得如下主要成果：高精度锆石U-Pb同位素定年得出：青阳-九华山复式岩体由四个阶段岩浆侵入形成的,从早到晚花岗闪长岩、二长花岗岩、钾长花岗岩、细粒花岗斑岩形成年龄分别为143.3±1.0Ma、37.6±1.5Ma、331.3±1.2Ma、132.0±2.0Ma。高家X]矿床花岗闪长岩和细粒花岗闪长斑岩的锆石U-Pb同位素年龄分别为144.9±1.2Ma和145±2Ma。高家X]、百丈岩矿床相关的岩浆岩分别对应青阳-九华山复式岩体早期第一阶段和晚期第四阶段,是复式岩体演化过程中的产物。岩石主量元素、微量元素、造岩矿物电子探针分析等研究表明,青阳-九华山复式岩体及钨钼矿相关岩浆岩均为壳幔源,可能来自相同的初始岩浆房,属于高钾钙碱性系列,准铝质-弱过铝质。电子探针分析表明：高家X]矿床矽卡岩中辉石为透辉石-钙铁辉石系列,石榴子石为钙铝榴石-钙铁榴石系列。其成分与百丈岩矿床差异较大,表明矽卡岩钨钼矿床中石榴子石和辉石成分不具有专属性。高家X]矿床石榴子石环带及共生石榴子石-辉石矿物对成分特征表明成矿环境是变化的,在岩浆流体出溶后,体系酸度升高、氧逸度降低,逐渐过渡到相对还原的环境。通过辉钼矿Re-Os定年方法,得到高家X]矿床成矿时代为146.1±4.8Ma。并结合已有资料,将皖南地区燕山期发育的钨钼矿床分为两期,分别为146-136Ma和134-128Ma。分别从矿区地层、构造及岩浆岩与成矿的关系方面探讨了成矿地质条件,并建立矿床的成矿模式,提出了找矿标志。本次工作增强了皖南地区燕山期钨钼矿床成矿规律的认识,并且对皖南地区后续的钨钼多金属矿产勘查具有一定的实际指导意义。
[Abstract]:Based on the project of China Geological Survey, "Deep Geological Survey of the Middle and Lower reaches of the metallogenic Belt of the Yangtze River", this paper systematically collects and comprehensively understands the regional geological background. The typical Qingyang-Jiuhuashan complex and its northern Gaojia X are selected as the research objects. Through field geological investigation and laboratory comprehensive identification, zircon U-Pb isotopic dating is carried out in combination with geochemistry analysis. The formation process of Qingyang-Jiuhuashan complex rock mass is discussed by means of Re-Os dating and mineral electron probe. The main results are as follows: high precision zircon U-Pb isotopic dating shows that the Qingyang-Jiuhuashan complex intruded by four stages of magma, granodiorite from early to late, monzomorphic granodiorite, monzomorphic granodiorite, granodiorite, monzogranite, etc. Potassium feldspar granite, The zircon U-Pb isotopic ages of granodiorite and fine-grained granodiorite are 144.9 卤1.2 Ma and 145 卤2 Ma.The zircon U-Pb isotopic ages of granodiorite and fine-grained granodiorite are 144.9 卤1.2 Ma and 145 卤2 Ma.Gaojia X respectively. The magmatic rocks associated with the Baizhang deposit correspond to Qingyang-Jiujiu, respectively. The first stage of the Huashan complex and the 4th stage of the late stage, The main elements, trace elements, petrogenic minerals, electron probe analysis and so on show that the Qingyang-Jiuhuashan complex rock mass and the related igneous rocks of tungsten and molybdenum ore are both crust-mantle source. Probably from the same initial magma chamber, belonging to the high-potassium calc-alkaline series, quasialuminum-weak peraluminous. Electron probe analysis shows that the pyroxene in skarn of the Gaojia X] deposit is diopside-calcium ferroxene series, The pomegranate is a series of calcium aluminite and calcium iron garnet. The composition of the garnet is quite different from that of the Baizhang rock deposit. The results show that the pomegranate and pyroxene compositions in skarn tungsten molybdenum deposit are not specific. The characteristics of pomegranate ring belt and symbiotic pomegranate pyroxene mineral pair in the Gaojia X deposit indicate that the metallogenic environment is changed, and the ore-forming environment is changed after the magmatic fluid dissolves. The acidity of the system increased, the oxygen fugacity decreased, and gradually transitioned to a relatively reductive environment. By using the molybdenum Re-Os dating method, the metallogenic age of the Gaojia X] deposit was obtained to be 146.1 卤4.8 Ma.The metallogenic age of the Gaojia X] deposit is 146.1 卤4.8 Ma. combined with the available data, The tungsten and molybdenum deposits developed in Yanshanian period in southern Anhui were divided into two periods, 146-136Ma and 134-128Ma. the metallogenic geological conditions were discussed from stratigraphy, structure and the relationship between magmatic rocks and mineralization, respectively, and the metallogenic model of the deposit was established. This work enhances the understanding of the metallogenic regularity of Yanshanian tungsten and molybdenum deposits in southern Anhui, and has certain practical guiding significance for the follow-up exploration of tungsten and molybdenum polymetallic minerals in southern Anhui.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.6

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