| 湖南城步火成岩锆石SHRIMP U-Pb年龄及其对江南造山带新元古代构造演化的约束 |
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| 引用本文： | 柏道远,贾宝华,刘伟,陈必河,刘耀荣,张晓阳.湖南城步火成岩锆石SHRIMP U-Pb年龄及其对江南造山带新元古代构造演化的约束[J].地质学报,2010,84(12):1715-1726. |
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| 作者姓名： | 柏道远 贾宝华 刘伟 陈必河 刘耀荣 张晓阳 |
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| 作者单位： | 1. 湖南省地质调查院,长沙,410011
2. 湖南省地质矿产勘查开发局,长沙,410011 |
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| 基金项目： | 中国地质调查局“湖南1:25万武冈市和永州市幅区调修测”项目、“中国地质构造区划综合研究与区域地质志修编”项目（1212010811032）及地质大调查项目（1212010610711） |
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| 摘 要： | 目前对新元古代中期江南造山带构造演化及钦杭结合带南西段构造性质存在不同认识。本文对湘西南城步地区新元古代火山岩和花岗岩进行了锆石SHRIMPU-Pb年龄测定并厘定其构造环境,从而为区域构造演化提供了约束。城步新元古代花岗岩侵入于云场里组变质火山-沉积地层中。云场里组变质火山岩与花岗岩的锆石SHRIMPU-Pb年龄分别为828±10Ma和805.7±9.2Ma。构造环境的地球化学判别图解表明花岗岩形成于岛弧环境;区域地质背景指示云场里组可能形成于活动陆缘弧前盆地。以城步火山岩和花岗岩研究为基础,结合区域地质资料,提出新元古代中期江南造山带西段构造演化过程:872～835Ma期间为陆缘盆地;835～820Ma期间俯冲造山,江南造山带形成基性—超基性岩和早阶段岛弧花岗闪长岩,东侧的城步地区为弧前盆地;820～810Ma期间江南造山带发生弧-陆碰撞;810～800Ma期间江南造山带进入后碰撞环境并形成晚阶段强过铝(黑云母)花岗岩,东侧城步地区因华南洋洋壳俯冲而形成新的岛弧;800Ma后华南进入伸展裂陷盆地演化阶段。上述认识揭示出扬子陆块东南缘的连续岛弧增生过程,同时为钦杭结合带南西段雪峰期"残留洋盆"属性提供了新证据。
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| 关 键 词： | 锆石SHRIMP U-Pb定年 花岗岩与火山岩 构造演化 新元古代 城步 江南造山带 |
| 收稿时间： | 2010/8/12 0:00:00 |
| 修稿时间： | 2010/8/31 0:00:00 |
Zircon SHRIMP U-Pb dating of the igneous rocks from Chengbu, Hunan, and their constraints on the Neoproterozoic tectonic evolution of Jiangnan orogenic belt |
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| baidaoyuan,Jia Baihu,Liu Wei,Chen Bihe,Liu Yaorong and Zhang Xiaoyang.Zircon SHRIMP U-Pb dating of the igneous rocks from Chengbu, Hunan, and their constraints on the Neoproterozoic tectonic evolution of Jiangnan orogenic belt[J].Acta Geologica Sinica,2010,84(12):1715-1726. |
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| Authors: | baidaoyuan Jia Baihu Liu Wei Chen Bihe Liu Yaorong and Zhang Xiaoyang |
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| Institution: | Hunan Bureau of Geology and Mineral Resources Exploration and development,Hunan Institute of Geology Survey,Hunan Institute of Geology Survey,Hunan Institute of Geology Survey,Hunan Institute of Geology Survey |
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| Abstract: | There exist different recognitions about tectonic evolution of the Jian gnan orogenic belt (JOB) and the tectonic affinity of the southwestern Qinzhou-Hangzhou suture zone in middle Neoproterozoic. Zircon SHRIMP U-Pb dating was pe rformed for the Neoproterozoic volcanic rocks and granites of the Chengbu area,Hunan,and their tectonic settings were discussed,which gives some constraints on regional tectonic evolution. The Chengbu Neoproterozoic granites intruded the metamorphic volcanic-sedimentary sequences ... |
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| Keywords: | zircon SHRIMP U-Pb dating granites and volcanic rocks tectonic evolution Neoproterozoic Chengbu Jiangnan orogenic belt |
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