| 中国海-西太平洋地区典型剖面的重-磁-震联合反演研究 |
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| 引用本文： | 张正一,范建柯,白永良,董冬冬.中国海-西太平洋地区典型剖面的重-磁-震联合反演研究[J].地球物理学报,2018,61(7):2871-2891. |
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| 作者姓名： | 张正一 范建柯 白永良 董冬冬 |
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| 作者单位： | 1. 中国科学院海洋研究所, 中国科学院海洋地质与环境重点实验室, 青岛 266071;2. 青岛海洋科学与技术国家实验室海洋地质过程与环境功能实验室, 青岛 266061;3. 中国科学院大学, 北京 100049;4. 中国石油大学(华东), 青岛 266580 |
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| 基金项目： | 全球变化与海气相互作用专项（GASI-GEOGE-02），国家自然科学基金（41506059），中国海陆地质地球物理系列图项目（GZH200900504）和中国科学院战略性先导科技专项（XDA11030102）联合资助. |
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| 摘 要： | 重-磁-震联合反演是获取地壳结构的重要方法.此次研究，我们主要基于全球最新的水深、重磁异常、沉积物厚度等数据，结合实测地震数据和前人研究成果，分析了中国海-西太平洋地区的莫霍面展布特征，并利用重磁震联合反演方法获得了跨越中国海-西太平洋典型剖面的地壳结构和异常体分布，揭示了陆壳到洋壳的典型变化规律.结果表明，从浙江地区到马里亚纳俯冲带，地壳结构大致呈现由厚到薄、由老到新、由复杂到简单的特征.浙江地区（扬子块体和华夏块体）地壳结构复杂，三层结构明显，地壳内断裂带发育，并伴有广泛的岩浆侵入；东海地区莫霍面起伏剧烈，地壳厚度变化较大，冲绳海槽地壳明显减薄，是其过渡壳性质的体现；西菲律宾海盆、九州-帕劳海脊、帕里西维拉海盆、马里亚纳俯冲带等构造单元地壳结构相对简单，二层结构明显.其中，西菲律宾海盆和帕里西维拉海盆地壳内部磁异常变化较为剧烈，海盆扩张过程中形成的磁异常体分布广泛，地壳厚度（5~8 km）明显小于陆壳；九州-帕劳海脊地壳厚度可达~20 km，缺失中地壳，表现为岛弧地壳结构；同源的西马里亚纳岛弧和东马里亚纳火山弧地壳结构相似，浅层磁异常体分布广泛，西马里亚纳岛弧地壳厚度（~17 km）略小于东马里亚纳火山弧（~20 km），体现了裂离的不对称性；马里亚纳海槽具有正常的洋壳结构（~7 km），但扩张中心未发生明显破裂.对比各构造单元地壳结构的异同点，我们进一步认识到，陆壳与洋壳之间不是孤立的，陆壳可能会演化出洋壳的结构或组分，板块的演化总是处于动态循环过程中.此研究加深了我们对中国海-西太平洋深部构造特征的整体理解，促进了我们对大陆边缘演化与板块相互作用的认识，深化了我国管辖海域及邻近地区的基础地质调查.
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| 关 键 词： | 中国海-西太平洋 重-磁-震联合反演 地壳结构 |
| 收稿时间： | 2017-05-13 |
Joint inversion of gravity-magnetic-seismic data of a typical profile in the China Sea-Western Pacific area |
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| ZHANG ZhengYi,FAN JianKe,BAI YongLiang,DONG DongDong.Joint inversion of gravity-magnetic-seismic data of a typical profile in the China Sea-Western Pacific area[J].Chinese Journal of Geophysics,2018,61(7):2871-2891. |
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| Authors: | ZHANG ZhengYi FAN JianKe BAI YongLiang DONG DongDong |
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| Institution: | 1. CAS Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China;2. Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061, China;3. University of Chinese Academy of Sciences, Beijing 100049, China;4. China University of Petroleum, Qingdao 266580, China |
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| Abstract: | The joint inversion of gravity-magnetic-seismic data is an important method to acquire the crustal structure. In this study, we analyse the Moho depth, the crustal structure and abnormal bodies distribution of a typical profile in the China Sea-Western Pacific area based on the latest bathymetric, gravity and magnetic anomaly, sediment thickness, measured seismic data and previous works. It reveals that the crust becomes thinner, younger and simpler from Zhejiang to the Mariana subduction zone. In Zhejiang area (including the Yangtze and the Cathaysia blocks), the crustal structure is complex and three-layered, in which, extensive magmatic intrusion bodies are distributed along the fault zones. In the East China Sea, the Moho depth and the crustal thickness change violently. Especially the Okinawa Trough, features the thinner and transitional crust. In the West Philippine Basin, the Kyushu-Palau Ridge, the Parece Vela Basin and the Mariana subduction zone, the crustal structure is simple and two-layered, and the magnetic anomalies change severely due to the wide distribution of abnormal bodies which were formed during the spreading period. The crustal thickness of the West Philippine Basin and the Parece Vela Basin (~5~8 km) are thinner than that of the typical continent, whereas the crust of the Kyushu-Palau Ridge has a thickness of~20 km and shows the nature of the arc, which is absent of the middle crust. In the Kyushu-Palau Ridge, the magnetic abnormal bodies formed during the spreading of the West Philippine Basin and the Parece Vela Basin. The West Mariana Arc and the East Mariana Volcanic Arc have similar crustal structure, in which the magnetic abnormal bodies distribute widely at the shallow depth. It indicates that they originated from the same arc. The crustal thickness of the West Mariana Arc (~17 km) is thinner than that of the East Mariana volcanic Arc (~20 km), suggesting the asymmetric splitting or spreading of the arc. The Mariana Trough has a normal oceanic structure (~7 km) and there is no obvious rupture in the spreading center. According to our research, we suggest that the continental crust is not isolated from the oceanic crust, and could transform into the oceanic crust. The plate evolution is always in the process of dynamic cycle. This study strengthens our understanding about the deep tectonic features of the China Sea-Western Pacific, the continental margin evolution and the plate interaction profoundly. |
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| Keywords: | China Sea-Western Pacific Joint inversion of gravity-magnetic-seismic data Crustal structure |
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