西藏林周地区帕那组火山岩时代及构造背景
发布时间：2019-04-19 14:12
【摘要】：林子宗火山岩在冈底斯带上广泛发育,其中帕那组火山岩的形成时代、构造背景和成因都存在一定争议。对林周地区帕那组火山岩进行了年代学和岩石地球化学研究,结果表明,研究区火山岩以流纹岩和英安岩为主,w(SiO2)极高,表现由高钾钙碱性系列向钾玄岩系列过渡的特征。帕那组火山岩微量元素地球化学特征显示LREE、LILE富集,HFSE亏损,Eu负异常,与岛弧火山岩地球化学特征相似。此外,帕那组流纹岩LA-ICP-MS锆石U-Pb年龄为(51.3±0.7)Ma,是目前为止冈底斯带中东段中的最老年龄。帕那组火山岩形成于后碰撞背景之下,其岩浆为地壳源区的部分熔融作用所形成。
[Abstract]:Linzizong volcanic rocks are widely developed in the Gangdise belt, in which the formation age, tectonic setting and genesis of the Pana formation volcanic rocks are controversial. The volcanic rocks of Pana formation in Linzhou area are studied by chronology and petrogeochemistry. The results show that the volcanic rocks in the study area are mainly rhyolite and andesite-dominated, w (SiO2. The characteristics of transition from high-K calc-alkaline series to K-basaltic series. The geochemical characteristics of trace elements in the volcanic rocks of Pana formation show that LREE,LILE is rich, HFSE is deficient and Eu is negative anomaly, which is similar to the geochemical characteristics of island arc volcanic rocks. In addition, the LA-ICP-MS zircon U-Pb age of the Pana formation rhyolite is (51.3 卤0.7) Ma, which is the oldest age in the Middle East segment of the Gangdise belt so far. The volcanic rocks of the Pana formation were formed under the background of post-collision, and the magma was formed by partial melting in the crust source region.
【作者单位】： 中国地质大学(武汉)地球科学学院;新疆地质调查院;中国地质大学(武汉)地质调查院;西安地质矿产勘查开发院;
【基金】：中国地质调查局项目(1212011221066;1212011121224)
【分类号】：P588.14
本文编号：2461013
[Abstract]:Linzizong volcanic rocks are widely developed in the Gangdise belt, in which the formation age, tectonic setting and genesis of the Pana formation volcanic rocks are controversial. The volcanic rocks of Pana formation in Linzhou area are studied by chronology and petrogeochemistry. The results show that the volcanic rocks in the study area are mainly rhyolite and andesite-dominated, w (SiO2. The characteristics of transition from high-K calc-alkaline series to K-basaltic series. The geochemical characteristics of trace elements in the volcanic rocks of Pana formation show that LREE,LILE is rich, HFSE is deficient and Eu is negative anomaly, which is similar to the geochemical characteristics of island arc volcanic rocks. In addition, the LA-ICP-MS zircon U-Pb age of the Pana formation rhyolite is (51.3 卤0.7) Ma, which is the oldest age in the Middle East segment of the Gangdise belt so far. The volcanic rocks of the Pana formation were formed under the background of post-collision, and the magma was formed by partial melting in the crust source region.
【作者单位】： 中国地质大学(武汉)地球科学学院;新疆地质调查院;中国地质大学(武汉)地质调查院;西安地质矿产勘查开发院;
【基金】：中国地质调查局项目(1212011221066;1212011121224)
【分类号】：P588.14
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