东海南海交接带重磁场特征及新生代盆地成因  

GEOPHYSICAL FEATURES AND CENOZOIC TECTONICS OF THE CONNECT ZONE BETWEEN THE EAST CHINA SEA AND SOUTH CHINA SEA

作　　者：吴时国[1] 郭军华[1] 刘展[2] 

机构地区：[1]中国科学院海洋研究所,青岛266071 [2]石油大学,东营257000

出　　处：《海洋地质与第四纪地质》2004年第3期49-55,共7页Marine Geology & Quaternary Geology

基　　金：中国科学院创新重要方向性项目(KZCX3 SW 219);国家自然科学基金项目(40276022);国家科学技术部重大基础研究项目(2000064704)

摘　　要：东海南海构造交接带及其邻近海区(简称交接带)位于中国东部大陆边缘,东邻俯冲板块边界。台湾以北是琉球海沟俯冲带,台湾以南为马尼拉海沟俯冲构造带。区域重磁资料分析结果表明,该东海陆架区存在3条重力高和2条重力低,重力高分别对应于闽浙隆起带、渔山低凸起和陆架外缘隆起,最大值高达50×10-5m·s-2;重力低对应于沉积盆地,最低值在台西南盆地,约为-20×10-5m·s-2。重磁特征表明东海盆地外缘台湾 钓鱼岛构造带具有明显的自由空间异常,磁场为平缓负异常,由古近系、白垩系或更老的变质岩及中新世的侵入岩组成,向南延伸至澎湖隆起。因为澎湖隆起具有高重力异常,放射性年龄表明这些碱性玄武岩形成于17 8～8MaBP,其特征同现在的琉球岛弧一样,可能是残留的古琉球岛弧。台西南盆地南侧(上陆坡)的凸起具有类似的幅度异常,呈ENE—WSW向,并消失在台西南盆地南段。新生代以来,盆地张裂活动具有不同时性,并向陆架边缘变得年轻。东海大陆边缘盆地属弧后残留盆地成因,多因岛弧的迁移而新生,但珠江口盆地则是被动大陆边缘裂陷作用所致。The connect zone between the East China Sea and South China Sea is located at East China Continental Margin. It is close to the convergent plate boundary, which is Ryukyu Trench in the north and Manila Trench in the south. There are three positive gravity anomalies and two negative zones. They reflect the uplift and basin. The maximum value is 50×10^(-5 )m·s^(-2), while the minimum is -20×10^(-5 )(m·s^(-2)). Since the Cenozoic the rifting occurred with different stages and becomes younger from the continental shelf to the continental slope. The geophysical field indicated the outer rise extended to the southwest of Taiwan and vanished there. The origin of the basin in the East China Sea should be the relict sedimentary basin formed by the southwest migration of the subduction zone, while the Pearl River basin formed by the rifting in the passive margin.

关 键 词：东海 南海 重磁场 新生代 张裂作用 

分 类 号：P738[天文地球—海洋地质] P722.6[天文地球—海洋科学]