朱群, 李之彤. 吉中地区含金火山岩系岩石地球化学特征[J]. 地质与资源, 1998, 7(2): 81-90. DOI: 10.13686/j.cnki.dzyzy.1998.02.001
    引用本文: 朱群, 李之彤. 吉中地区含金火山岩系岩石地球化学特征[J]. 地质与资源, 1998, 7(2): 81-90. DOI: 10.13686/j.cnki.dzyzy.1998.02.001
    Zhu Qun, Li Zhitong. THE GEOCHEMICAL FEATURE OF AURIFEROUS VOLCANIC ROCK SERIES IN CENTRAL JILIN[J]. Geology and Resources, 1998, 7(2): 81-90. DOI: 10.13686/j.cnki.dzyzy.1998.02.001
    Citation: Zhu Qun, Li Zhitong. THE GEOCHEMICAL FEATURE OF AURIFEROUS VOLCANIC ROCK SERIES IN CENTRAL JILIN[J]. Geology and Resources, 1998, 7(2): 81-90. DOI: 10.13686/j.cnki.dzyzy.1998.02.001

    吉中地区含金火山岩系岩石地球化学特征

    THE GEOCHEMICAL FEATURE OF AURIFEROUS VOLCANIC ROCK SERIES IN CENTRAL JILIN

    • 摘要: 吉林中部含金火山岩分早石炭世余富屯期,RbSr年龄301Ma,略偏低;晚三叠世南楼山期RbSr年龄222Ma.余富屯组火山岩系细碧角斑岩组合:细碧岩、细碧玢岩、角斑岩、石英角斑岩;南楼山组岩石组合主要为安山岩、英安岩、流纹岩及玄武安山岩、安粗岩。在岩石化学上二者均属亚碱性系列钙碱性火山岩系。其中,余富屯组属钠质类型,南楼山组属钾质类型。二者的稀土总量中低(111×109~256×109),属轻稀土富集型,分布模式为右倾曲线,略有负铕异常(δEu0.93~0.75)。其Au的含量(平均)分别为28×109和72×109,明显高.锶初始值分别为0.70492和0.70533,较低,反映物质来源较深。研究表明,余富屯期火山岩形成于拉张环境,即吉中晚古生代裂陷槽;而南楼山期火山岩则为自晚三叠世开始的活动大陆边缘产物

       

      Abstract: The auriferous volcanic rocks in central Jilin may be divided into Early Carboniferous Yufutun stage and Late Triassic Nanloushan stage with RbSr ages of 301Ma and 222Ma respectively.Yufutun formation consists of spilite, spilitic porphyrite, keratophyre and quartz keratophyre.Nanloushan formation consists of andesite, dacite, rhyolite, basaltic andesite and latite.They both petrochemically belong to calcitealkaline volcanic rock series of subalkaline system. Yufutun formation is of sodium type;and Nanloushan formation, potassium type.The Σ REE content(111×10-9~256×10-9) is enriched in LREE, with a right sloping distribution pattern and negative Eu anomaly(WEu0.93~0.75).In the above two rock associations, the mean content of Au are 28×10-9 and 72×10-9 respectively, the initial volume of Sr are 0.70492 and 0.70533 respectively.The study shows that Yufutun stage volcanic rock formed in a tensional environment, that is MiddleLate Palaeozoic riftdepression syncline, and Nanloushan stage volcanic rock was the products of active continental margin beginning from Late Triassic.

       

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