K-Ar Geochronology of the Caledonian Event in the Xuefeng Uplift
K-Ar Geochronology of the Caledonian Event in the Xuefeng Uplift
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发表时间：
2010
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通讯作者：
Zhang Li
中科院分区：
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作者：
Zhang Li
详细的构造变形分析表明，雪峰隆起经历了加里东期、印支期、晚侏罗世末至早白垩世早期和早白垩世末至晚白垩世早期四期构造热事件，晚期三期褶皱走向为NWW、NE—NNE和近NS，加里东走向 雪峰隆起北部板岩伊利石K-Ar年代学显示，隆起确实发生过加里东构造—热事件，早在419Ma，( 最早的晚志留世）。419～389Ma（晚志留世至中泥盆世）的冷却年龄揭示了加里东的揭顶和隆起的隆起时间。华南加里东变形事件直接影响雪峰隆起本身，影响的西边界可能大致到张家界—花园—凯里断裂带。
Detailed structural deformation analysis indicate that the Xuefeng Uplift underwent four phases tectono—thermal events,Caledonian,Indosinian,the end of Late Jurassic to the earliest of Early Cretaceous and the end of Early Cretaceous to the earliest of Late Cretaceous,the orientations of the late three phases folds are NWW,NE—NNE and nearly NS,the orientation of Caledonian deformation can not be identified accurately due to the influence of the late deformation overprinting.XRD analysis of the Banxi Group slate in the northern Xuefeng Uplift suggest a lower green-schist facies metamorphism.Caledonian tectono—thermal event indeed taken place in the uplift showed by the K-Ar geochronology of slate illite of the Banxi Group and it happened as earlier as 419Ma,( the earliest of Late Silurian ).The cooling ages of 419～389Ma (Late Silurian to Middle Devonian) demonstrate the Caledonian unroofing and the uplifting time of the uplift.Caledonian deformation event of the South China influenced directly the Xuefeng Uplift itself,and the western boundary of the influence possibly to the Zhangjiajie—Huayuan—Kaili fault zone approximately.