| 华南东部地区上地幔P波速度结构研究 |
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| 引用本文： | 王晓冉,李秋生,张洪双,郭陈澔.华南东部地区上地幔P波速度结构研究[J].世界地质,2018,37(2):620-626. |
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| 作者姓名： | 王晓冉 李秋生 张洪双 郭陈澔 |
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| 作者单位： | 1. 中国地质科学院 地质研究所, 北京 100037;2. 自然资源部“深地动力学”重点实验室, 北京 10037;3. 中央大学 地球科学学院, 台湾 桃园市 32001 |
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| 基金项目： | 国家深地资源勘查开采重点专项（2016YFC0600302）和国家自然科学基金项目（41574092）及中国地质调查局国土资源调查项目（DD20179354）联合资助. |
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| 摘 要： | 基于华南东部宽频地震流动台阵的观测资料,采用三维有限差分走时成像法(FDtomo),开展了华南东部地区地壳-上地幔三维P波速度结构成像研究,结果显示华南东部地区水平面内速度分布差异较大,约163 km以上的地壳到上地幔下扬子地块存在近EW向的相对低速异常,而华夏地块则为高速异常,约163 km以下的上地幔下扬子地块和华夏板块速度异常发生反转,且两者大致以江山—绍兴断裂带为界呈反对称,对比显著。笔者认为该结构特征反映了晚中生代扬子克拉通岩石圈的拆沉过程。这一成果对理解中国东部中生代以来的构造演化以及壳幔的动力学过程提供了新的证据。
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| 关 键 词： | 有限差分 走时层析成像 华南东部 速度结构 板块俯冲 岩石圈拆沉 |
| 收稿时间： | 2018-03-06 |
| 修稿时间： | 2018-05-28 |
Study of P-wave velocity structure in upper mantle in eastern South China |
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| WANG Xiao-ran,LI Qiu-sheng,ZHANG Hong-shuang,CHEN Hao.Study of P-wave velocity structure in upper mantle in eastern South China[J].World Geology,2018,37(2):620-626. |
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| Authors: | WANG Xiao-ran LI Qiu-sheng ZHANG Hong-shuang CHEN Hao |
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| Institution: | 1. Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;2. Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources, Beijing 100037, China;3. College of Earth Science, National Central University, Taoyuan 32001, Taiwan, China |
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| Abstract: | Based on the observed broadband seismic data from temporary array in the eastern part of South China, the authors utilize the three-dimensional finite difference travel time tomography method to image the three-dimensional P-wave velocity structure of crust-upper mantle in eastern South China. The imaging results show that the velocity distribution varies obviously in the horizontal plane. In the crust-upper mantle above about 163 km, there exist EW-oriented low-velocity anomalies beneath the Lower Yangtze block, while the high-velocity anomalies exist in the Cathaysia block. However, in the upper mantle below 163 km, the velocity anomalies in the lower Yangtze block and the Cathaysia block are reversed. They are reverse symmetric, roughly bounded by the Jiangshan-Shaoxing fault, with significant contrast. The authors believe that these structural features reflect the demolition process of the Yangtze Craton lithosphere in Late Mesozoic. These results provide new evidence to the understanding of the structural evolution and dynamic process of crust-mantle since the Mesozoic in eastern China. |
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| Keywords: | finite difference arrival time tomography eastern South China velocity structure plate subduction lithosphere demolition |
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