胡家博, 冯庆来, SenebouttalathVongpaseuth, XayyavongsaVongdavanh. 2023: 老挝西北部班康姆金矿区火山岩地质年龄、地球化学特征及其对金矿勘查的启示. 地质通报, 42(11): 1967-1982. DOI: 10.12097/j.issn.1671-2552.2023.11.013
    引用本文: 胡家博, 冯庆来, SenebouttalathVongpaseuth, XayyavongsaVongdavanh. 2023: 老挝西北部班康姆金矿区火山岩地质年龄、地球化学特征及其对金矿勘查的启示. 地质通报, 42(11): 1967-1982. DOI: 10.12097/j.issn.1671-2552.2023.11.013
    HU Jiabo, FENG Qinglai, SENEBOUTTALATH Vongpaseuth, XAYYAVONGSA Vongdavanh. 2023: Geochronology and geochemistry characteristics of the volcanic rocks in Pangkuam gold deposit area, Northwestern Laos and its implication for gold exploration. Geological Bulletin of China, 42(11): 1967-1982. DOI: 10.12097/j.issn.1671-2552.2023.11.013
    Citation: HU Jiabo, FENG Qinglai, SENEBOUTTALATH Vongpaseuth, XAYYAVONGSA Vongdavanh. 2023: Geochronology and geochemistry characteristics of the volcanic rocks in Pangkuam gold deposit area, Northwestern Laos and its implication for gold exploration. Geological Bulletin of China, 42(11): 1967-1982. DOI: 10.12097/j.issn.1671-2552.2023.11.013

    老挝西北部班康姆金矿区火山岩地质年龄、地球化学特征及其对金矿勘查的启示

    Geochronology and geochemistry characteristics of the volcanic rocks in Pangkuam gold deposit area, Northwestern Laos and its implication for gold exploration

    • 摘要: 班康姆(Pangkuam)金矿是近年来在老挝西北部巴莱(Paklay)地区经过详查的、具有寻找超大矿床潜力的大型金矿床,开展该金矿区及周围地质研究,对老挝西北部金矿形成规律及深部外围找矿具有重要意义。对班康姆金矿矿区及附近火山岩进行了岩石学、年代学和地球化学研究,得到玄武岩、绿泥石化角闪安山岩、绢云母化角闪安山岩的LA-ICP-MS锆石U-Pb年龄分别为304.5±3.9 Ma、309.4±3.1 Ma和314.4±3.6 Ma,属于晚石炭世中晚期岩浆活动的产物。地球化学分析表明火山岩样品TiO2、Ni、Cr等元素含量低,K2O及Al2O3含量高,富集轻稀土元素和大离子亲石元素,亏损高场强元素,为一套钙碱性中基性安山岩-粗安岩-钾玄岩系列,属于大陆边缘弧岩浆岩,可能为黎府洋俯冲闭合后的产物。晚石炭世中基性火山岩层系的存在,暗示老挝西北部地区的金矿形成规律还需要进一步研究,外围找矿需要关注更多的火山岩。

       

      Abstract: Pangkuam gold deposit is a large gold deposit that has been detailedly investigated in northwestern Laos and shows the potential becoming a super-large mineral deposit.It is of great significance to carry out research on this deposit and its surrounding area for understanding the formation and exploration direction of gold deposit in NW Laos.In this study, we investigate the petrological, geochronological and geochemical studies of volcanic rocks in Pangkuam mining area.The results show that the LA-ICP-MS zircon U-Pb ages of the basalt, chlorite hornblende andesite, and sericite hornblende andesite is 304.5 ±3.9 Ma, 309.4 ±3.1 Ma, and 314.4 ±3.6 Ma, respectively, and these ages belong to the middle to late Late Carboniferous.These volcanic rocks show low TiO2, Ni, Cr, and high Al2O3 content.In addition, they are enriched with LREEs and LILEs but depleted in HFSEs.These geochemical characteristics tested by XRF and ICP suggest that these samples are a set of calc-alkaline andesite-shoshonite rocks and exhibit a geochemical affinity to active continental marginal arc volcanic rocks.In summary, these samples may be products of subduction and closure of the Loei ocean.The exist of intermediate-basic volcanic rock series of the Late Carboniferous may indicate that the formation of gold deposit in NW Laos needs further study, and peripheral prospecting may need to focus on more volcanic rocks.

       

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