| 青藏高原东部贡觉盆地新生代火山岩的K-Ar稀释法年龄 |
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| 引用本文： | 李忠雄 陈智梁 李修忠 C.Gizbert B.C.Burchfiel.青藏高原东部贡觉盆地新生代火山岩的K-Ar稀释法年龄[J].地球科学,2004,29(3):278-282. |
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| 作者姓名： | 李忠雄 陈智梁 李修忠 C.Gizbert B.C.Burchfiel |
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| 作者单位： | 中国地质大学资源学院,湖北武汉,430074;成都地质矿产研究所,四川成都,610082;成都地质矿产研究所,四川成都,610082;中国地质大学资源学院,湖北武汉,430074;Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA |
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| 基金项目： | 中美合作项目“青藏高原东部地质、地球物理和大地测量研究” |
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| 摘 要： | 通过新生代高钾钙碱性中、酸性火山岩的年代学研究来了解青藏高原的隆升特征，首次报道了藏东贡觉盆地新生代7个火山岩样品的K-Ar定年结果．全岩和黑云母的表面年龄均在40．8～46．2Ma间(平均值为44．2Ma)．样品中放射成因Ar与K构成了一条相关性良好的、几乎通过原点的线性等时线，表明它们有相同的成因和相近的形成时代。而且样品中可能既无过剩Ar，也无放射成因Ar的丢失，代表着真实的成岩年龄(始新世中期)．火山活动发生在印度—欧亚板块碰撞(50 Ma左右)后形成的构造环境中。受陆内水平剪切—走滑断裂带控制．结合前人对藏东地区岩浆活动的年代学研究成果．表明青藏高原东缘新生代岩浆活动具多期性．这种多期性可能反映着青藏高原阶段性隆升的壳—幔相互作用。
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| 关 键 词： | K-Ar稀释法 火山岩 新生代 贡觉盆地 藏东 |
| 文章编号： | 1000-2383(2004)03-0278-05 |
K-Ar Ages of Cenozoic Volcanic Rocks from Gongjue Basin in Eastern Tibet |
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| LI Zhong-xiong.K-Ar Ages of Cenozoic Volcanic Rocks from Gongjue Basin in Eastern Tibet[J].Earth Science-Journal of China University of Geosciences,2004,29(3):278-282. |
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| Authors: | LI Zhong-xiong |
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| Institution: | LI Zhong-xiong~ |
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| Abstract: | Based on the isotopic chronologic results of Cenozoic volcanic rocks from Gongjue basin in eastern Tibet, the uplifting of the Tibetan plateau was studied. The K-Ar diluted ages of seven volcanic rocks from the Gongjue basin in eastern Tibet are firstly reported. Apparent ages of the whole rock and their biotite are 40.8 to 46.2 Ma with an average of 44.2 Ma. Radiogenic Ar and K of the samples compose an isochron line with high correlation coefficient, which almost passes through the origin. The result indicates that there is neither residual Ar nor loss of radiogenic Ar in these samples. Therefore, they give the eruption ages of the volcanic rocks (i.e. middle Eocene). The volcanic activities in the studied region occurred in the post-collision tectonic setting of Indian-Eurasia plate collision (about 50 Ma) and were controlled by intra-continental horizontal shear faults. Evidences including the published data show that the Cenozoic volcanic activities in eastern Tibet vary greatly. The variety can be considered as the product of the crust-mantle interaction due to the multi-stage uplift in the (Tibetan) plateau. |
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| Keywords: | K-Ar dating volcanic rock Cenozoic Gongjue basin eastern Tibet |
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