| 中亚造山带东段浅表构造速度结构——深地震反射剖面初至波层析成像的揭露 |
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| 引用本文： | 谢樊,王海燕,侯贺晟,高锐.中亚造山带东段浅表构造速度结构——深地震反射剖面初至波层析成像的揭露[J].吉林大学学报(地球科学版),2021,51(2):584-596. |
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| 作者姓名： | 谢樊 王海燕 侯贺晟 高锐 |
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| 作者单位： | 1. 中山大学地球科学与工程学院, 广州 510275;2. 中国地质科学院地质研究所, 北京 100037;3. 中国地质科学院, 北京 100037;4. 吉林大学地球探测科学与技术学院, 长春 130026 |
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| 基金项目： | 国家自然科学基金项目(41430213,41590863);国家重点研发计划项目(2107YFC0601301,2107YFC0601300);中国地质调查局项目(DD20160207,DD20190010)。 |
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| 摘 要： | 为揭示中亚造山带浅表结构，对地壳演化与深部过程提供浅部精准约束，利用横过中亚造山带东段（奈曼旗—东乌珠穆沁旗）长达400 km的深地震反射剖面共2 186炮的初至波走时数据，运用初至波层析成像方法获得了自地表向下约3 km厚度的浅表速度结构精细模型。通过模型计算了沉积厚度变化与基岩起伏特征，并在贺根山和西拉木伦缝合带附近获得了呈低速特征的弧前沉积盆地规模与沉积厚度变化特征；在此基础上，综合速度模型与深地震反射剖面的强振幅反射信息，建立了符合剖面南北两侧的古亚洲洋双向俯冲并与中部的残存微陆块发生拼合的构造模型。结果表明：研究区的沉积厚度在0.3~3.0 km范围内变化，区内存在多期岩浆活动及活动构造，林西地区隐伏连续分布的高速结构多为造山花岗岩所导致；古亚洲洋消亡过程在经数亿年演变后仍能在大陆边缘的浅表构造中有迹可循。
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| 关 键 词： | 中亚造山带 浅表速度结构 深地震反射剖面 初至波走时层析成像 |
| 收稿时间： | 2020-01-01 |
Near-Surface Fine Velocity Structure in Eastern Segment of Central Asian Orogenic Belt:Revealed by First-Arrival Wave Tomography from Deep Seismic Reflection Profile |
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| Xie Fan,Wang Haiyan,Hou Hesheng,Gao Rui.Near-Surface Fine Velocity Structure in Eastern Segment of Central Asian Orogenic Belt:Revealed by First-Arrival Wave Tomography from Deep Seismic Reflection Profile[J].Journal of Jilin Unviersity:Earth Science Edition,2021,51(2):584-596. |
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| Authors: | Xie Fan Wang Haiyan Hou Hesheng Gao Rui |
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| Institution: | 1. School of Earth Science and Geological Engineering, Sun Yat-Sen University, Guangzhou 510275, China;2. Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;3. Chinese Academy of Geological Sciences, Beijing 100037, China;4. College of GeoExploration Science and Technology, Jilin University, Changchun 130026, China |
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| Abstract: | To reveal the superficial structure of the Central Asian orogenic belt, provide precise constraints on the evolution and deep processes of the crust, a fine model of near-surface velocity structure with a thickness about 3 000 m was obtained through the first-arrive wave tomography based on a total of 2 186 shots across a 400 km long deep seismic reflection profile in the eastern section of the Central Asian orogenic belt(Naiman Banner-East Wuzhumuqin Banner). This model calculated the variation of sedimentary thickness and the bedrock undulation, and the scale and thickness of the forearc basin with low-velocity characteristics were obtained near the Hegen Mountain suture zone and Xar Moron suture zone. Based on the near-surface velocity structure and the strong amplitude reflection information of the deep seismic reflection profile, a structure model was inferred that coincides with the bidirectional subduction of the paleo-Asian Ocean on the north and south sides of the profile and merges with the residual microcontinent block in the middle. The results showed the deposition thickness varies from 0.3 to 3.0 km, there were multi-periodic magmatic and tectonic activities in the study area, and the buried and continuous high velocity structures in Linxi area are mostly caused by orogenic granites. Through our work, the subduction process of the paleo-Asian Ocean can still be traced in the near-surface velocity structure of the continental margin after hundreds of millions of years of evolution. |
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| Keywords: | Central Asian orogenic belt near-surface velocity structure deep seismic reflection profile first arrival travel-time tomography |
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