| 长江中下游成矿带三维S波速度结构及对深部过程的约束 |
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| 引用本文： | 徐峣,吕庆田,张贵宾,江国明,张昌榕,单希鹏,吴强.长江中下游成矿带三维S波速度结构及对深部过程的约束[J].地球物理学报,2015,58(12):4373-4387. |
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| 作者姓名： | 徐峣 吕庆田 张贵宾 江国明 张昌榕 单希鹏 吴强 |
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| 作者单位： | 1. 中国地质大学(北京)地球物理与信息技术学院, 北京 100083;2. 中国地质科学院矿产资源研究所, 国土资源部成矿作用与资源评价重点实验室, 北京 100037;3. 中国地质科学院地球深部探测中心, 北京 100037;4. 安徽省勘查技术院, 合肥 230031 |
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| 基金项目： | 地质调查工作项目(1212011220243,1212011220244),国家深部探测专项第3项(SinoProbe-03),"十二五"国家科技支撑计划课题(2011BAB04B01)联合资助. |
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| 摘 要： | 利用73个固定台站记录的163个远震事件数据,采用多道互相关技术挑选了5524条S波到时数据,并对S波到时数据进行地壳校正,在此基础上采用天然地震层析成像方法和远震S波到时信息,获得了长江中下游成矿带上地幔的三维S波速度结构模型.研究结果表明:(1)研究区域上地幔存在着明显的低速异常,且走向与成矿带相同,可能为上涌的软流圈热物质;(2)研究区域地幔过渡带和上地幔底部存在着明显的高速异常,可能为俯冲的古太平洋板块和拆沉的岩石圈;(3)成矿带上地幔的低速异常呈现由南向北逐渐变浅的空间分布特征,该特征表明软流圈热物质由南向北上涌.综合分析认为,成矿带中生代大规模岩浆活动和成矿作用的深部过程主要与岩石圈的拆沉密切相关.
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| 关 键 词： | 长江中下游成矿带 天然地震层析成像 深部动力学 软流圈上涌 岩石圈拆沉 古太平洋板块俯冲 |
| 收稿时间： | 2015-06-03 |
S-wave velocity structure beneath the Middle-Lower Yangtze River Metallogenic Belt and the constraints on the deep dynamic processes |
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| XU Yao,LV Qing-Tian,ZHANG Gui-Bin,JIANG Guo-Ming,ZHANG Chang-Rong,SHAN Xi-Peng,WU Qiang.S-wave velocity structure beneath the Middle-Lower Yangtze River Metallogenic Belt and the constraints on the deep dynamic processes[J].Chinese Journal of Geophysics,2015,58(12):4373-4387. |
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| Authors: | XU Yao LV Qing-Tian ZHANG Gui-Bin JIANG Guo-Ming ZHANG Chang-Rong SHAN Xi-Peng WU Qiang |
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| Institution: | 1. School of Geophysics and Information Technology, China University of Geosciences, Beijing 100083, China;2. MLR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China;3. China Deep Exploration Center-SinoProbe Center, Chinese Academy of Geological Sciences, Beijing 100037, China;4. Geological Exploration Technologies Institute of Anhui Province, Hefei 230031, China |
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| Abstract: | The Middle-Lower Yangtze River Metallogenic Belt (MLYRMB) is one of the most important metallogenic belts in China and plenty of researches have done in this belt. In this paper, we determined a 3-D S-wave velocity structure of the mantle down to 600 km depth beneath the MLYRMB by using 5524 S-wave relative travel times collected from 163 teleseismic events recorded by 73 static seismic stations located within this belt and its adjacent areas. The tomography method used in our study is the TOMOG3D, which has been widely used in a lot of tomography studies and gained a lot of achievements. In the data processing, we chose the data with high signal to noise ratio according to 3 criteria and used an automatic method called MMCC to pick up the relative travel times precisely. Besides that, we have also applied the crust correction method to reduce the effect caused by the crustal inhomogeneity, in order to make the final result more accurate. Our result shows:(1)there exist a low velocity anomaly in the upper mantle and the trend of the anomaly is consist with MLYRMB, which maybe the upwelling of asthenosphere;(2)there exist a high velocity anomaly in the mantle transition zone and the bottom of upper mantle which maybe the subduction of paleo-Pacific plate and the delaminated lithosphere; (3) the low velocity anomaly beneath the belt has a trend that is gradually shallower from the south to the north, which means the up welling of asthenosphere start from south to north.#br#Combining a lot of studies about geophysics, geochemistry, geology and so on, we assumed that the formation of the MLYRMB in Mesozoic was mainly caused by the delamination of lithosphere. |
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| Keywords: | The Middle-Lower Yangtze River Metallogenic Belt Seismic tomography Deep dynamic processes Upwelling of asthenosphere Delamination of lithosphere Subduction of paleo-Pacific plate |
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