内蒙古维拉斯托锡多金属矿床地质特征及成因探讨

发布时间：2018-06-06 00:38

  本文选题：维拉斯托 + 锡多金属矿　； 参考：《中国地质大学(北京)》2016年硕士论文

【摘要】：大兴安岭西坡是我国重要的银铜铅锌多金属成矿带。2014年在维拉斯托银铜铅锌多金属矿床外围与深部发现锡矿化,目前已探明锡金属资源量8.37万吨(332+333),规模达大型,取得了大兴安岭西坡寻找锡矿的重大找矿突破。本文选取维拉斯托锡多金属矿床为研究对象,在加强矿区地质、矿体特征分析的基础上,综合应用岩石学、矿相学、岩矿地球化学、同位素年代学、流体包裹体等测试分析技术,开展了维拉斯托锡多金属矿床地质地球化学特征与矿床成因研究。论文取得的主要成果和认识如下:1、在对维拉斯托锡多金属矿床矿体特征、矿石类型、矿物穿插关系等进行详细的野外观察基础上,结合室内岩石学、矿相学及显微电子探针观测,将维拉斯托锡多金属矿床划分为3个成矿期次、6个成矿阶段。2、维拉斯托锡多金属矿床的岩石地球化学特征表明,与成矿有关的石英斑岩具有富硅、富碱、高钾、贫钙、过铝质,高分异的特征,演化程度高,属于高钾钙碱性系列,具碱长花岗岩的典型特征;岩石中强烈亏损Ba、Sr、Ti、P,富集Rb与La、Ce、Pr、Nd、Sm及Th、U;稀土元素分布型式呈 V‖型,强烈的Eu负异常。其中,与成矿有关的天河石化石英斑岩LA-ICP-MS锆石U-Pb加权平均年龄为136.25±0.68Ma;矿石中辉钼矿的Re-Os同位素等时线年龄为116.6±1.8Ma。矿床的成岩成矿时代为早白垩世。3、维拉斯托锡多金属矿床中的流体包裹体主要以气液两相包裹体为主,主成矿期完全均一温度为220~321℃。初始成矿流体为高温、中-低盐度、富挥发分的H2O-NaCl体系,成矿早、中阶段为中-高温、中-低盐度的H2O-NaCl体系,成矿晚阶段则为低温、中低盐度的H2O-NaCl体系。初步确定维拉斯托锡多金属矿床为中—高温岩浆热液矿床。
[Abstract]:The west slope of the Daxinganling Mountains is an important silver-copper-lead-zinc polymetallic metallogenic belt in China. Tin mineralization was discovered in the periphery and deep of the Silver-Cu-Pb-Zn polymetallic deposit in Virasto in 2014. At present, 83700 tons of tin metal resources have been discovered, with a large scale. A great breakthrough has been made in the exploration of tin ore on the west slope of Daxing'anling Mountains. In this paper, based on the analysis of geological and orebody characteristics, petrology, mineralogy, geochemistry and isotopic chronology are comprehensively applied. The geological and geochemical characteristics and genesis of the Villastosi _ polymetallic deposit were studied by fluid inclusion test and analysis techniques. The main achievements and understandings in this paper are as follows: 1. On the basis of detailed field observation of orebody characteristics, ore types, mineral intercalation relationships and so on, the paper combines indoor petrology. According to the metallographic and microelectronic probe observations, the Vila Stosid metal deposit is divided into 3 metallogenic stages and 6 metallogenic stages. The petrogeochemical characteristics of the Villastosi polymetallic deposit indicate that the ore-forming quartz porphyry is silicon-rich, and the ore-forming quartz-porphyry is rich in silicon. Rich in alkali, high potassium, poor calcium, peraluminous, high grade, high degree of evolution, belonging to high potassium calc-alkaline series, with typical characteristics of alkali feldspar granite; strongly depleted Bazrsrsrhinophosphate in rocks, enriched RB and Laxie PrNdSm and Thu U; REE distribution pattern is V type. Strong negative EU anomalies. Among them, the U-Pb weighted mean zircon U-Pb age of the quartz porphyry LA-ICP-MS is 136.25 卤0.68 Ma, and the Re-Os isochron age of molybdenum in the ore is 116.6 卤1.8 Ma. The diagenetic and metallogenic epoch of the deposit is early Cretaceous. 3. The fluid inclusions are mainly gas-liquid two-phase inclusions, and the homogenization temperature of the main metallogenic period is 220 ~ 321 鈩，

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