内蒙古核桃坝地区流纹斑岩的地球化学特征及与铀富集的关系

发布时间：2018-07-04 22:39

  本文选题：核桃坝 + 流纹斑岩　； 参考：《现代地质》2017年02期

【摘要】：内蒙古核桃坝地区流纹斑岩体与该区铀成矿有着密切关系,为了寻求找矿突破,通过地球化学和岩浆与构造演化等方法,着重讨论流纹斑岩和构造与铀富集的关系。该流纹斑岩体位于多伦火山盆地榛子山破火山口南部,岩石富硅(w(SiO_2)=70.15%~78.58%),富碱(w(Na_2O+K_2O)=7.49%~10.82%),属钾质(w(K_2O)=5.28%~9.30%);A/CNK的值在0.84~1.28之间,在火山岩TAS分类图解中全部样品均落入亚碱性流纹岩范围内,属于亚碱性系列流纹岩类;稀土总量高(∑REE=254.47×10~(-6)~499.99×10~(-6)),其中轻稀土元素富集,重稀土元素亏损,轻重稀土分馏程度强;亲石元素Rb、Th相对富集,特别是U含量(6.66×10~(-6)~966.00×10~(-6))异常富集,部分数据极高,而Sr和Eu明显亏损。岩石岩浆物质来源于下地壳的部分熔融,侵位于后碰撞构造环境,属于A2型花岗岩类型。伸展构造背景下的富铀流纹斑岩侵位、后期促进铀运移富集的成矿构造及富铀热液随构造上移并进一步萃取等多种事件共同作用,最终促成了核桃坝铀矿床的形成。
[Abstract]:The fluid porphyry body in Juuba area, Inner Mongolia is closely related to uranium mineralization in this area. In order to seek a breakthrough in prospecting, the relationship between flow porphyry and tectonics and uranium enrichment is discussed through geochemical and magmatic and tectonic evolution methods. It is located in the south of hazelzishan crater in Dolon volcanic basin. The rock is rich in (w (SiO2) 70.15% (78.58%), alkali-rich (w (Na2O K2O) 7.490.82%), belongs to potassium (w (K2O) 5.280.30%). In the taxonomic map of volcanic rocks, all the samples fall into the range of subalkaline rhyolite. It belongs to the subalkaline series rhyolite, the total amount of rare earth (鈭，

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