| 南海西南次海盆与南沙地块的OBS探测和地壳结构 |
| |
| 引用本文： | 丘学林,赵明辉,敖威,吕川川,郝天珧,游庆瑜,阮爱国,李家彪.南海西南次海盆与南沙地块的OBS探测和地壳结构[J].地球物理学报,2011,54(12):3117-3128. |
| |
| 作者姓名： | 丘学林 赵明辉 敖威 吕川川 郝天珧 游庆瑜 阮爱国 李家彪 |
| |
| 作者单位： | 1. 中国科学院边缘海地质重点实验室,中国科学院南海海洋研究所, 广州 510301;
2. 中国科学院油气资源研究重点实验室,中国科学院地质与地球物理研究所, 北京 100029;
3. 国家海洋局海底科学重点实验室,国家海洋局第二海洋研究所,杭州 310012 |
| |
| 基金项目： | 国家重点基础研究发展计划(973计划)，中国科学院创新项目，国家自然科学基金，中国地质调查局项目 |
| |
| 摘 要： | 跨越南海西南次海盆南部陆缘和南沙地块中部的OBS973-1测线是南海南部首次采集的海底地震仪(OBS)广角反射与折射深地震测线,本文通过震相分析和走时正演拟合,获得了沿测线的二维纵波速度结构模型.模拟结果显示表层沉积物速度2.5～4.5 km/s,厚度1000～3000m,局部基底面起伏较大.结晶基底的速度从顶部的4....
|
| 关 键 词： | 西南次海盆 南沙地块 海底地震仪 地壳结构 共轭陆缘 |
| 收稿时间： | 2011-07-19 |
OBS survey and crustal structure of the Southwest Sub-basin and Nansha Block, South China Sea |
| |
| QIU Xue-Lin
,
ZHAO Ming-Hui
,
AO Wei
,
LU Chuan-Chuan
,
HAO Tian-Yao
,
YOU Qing-Yu
,
RUAN Ai-Guo
,
LI Jia-Biao.OBS survey and crustal structure of the Southwest Sub-basin and Nansha Block, South China Sea[J].Chinese Journal of Geophysics,2011,54(12):3117-3128. |
| |
| Authors: | QIU Xue-Lin ZHAO Ming-Hui AO Wei LU Chuan-Chuan HAO Tian-Yao YOU Qing-Yu RUAN Ai-Guo LI Jia-Biao |
| |
| Institution: | 1. Key Laboratory of Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China;
2. Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;
3. Key Laboratory of Submarine Geoscience, The Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China |
| |
| Abstract: | OBS973-1 is a wide angle reflection and refraction deep seismic line using Ocean Bottom Seismometers (OBS), deployed for the first time in the southern part of South China Sea. The line crosses the southern margin of the Southwest Sub-basin and the middle part of Nansha Block. By seismic phase analysis and travel time fitting, a 2D P-wave velocity model along the line is constructed. The modeling results show that the surface sedimentary layer has a velocity of 2.5~4.5 km/s and a thickness of 1000~3000m, with locally rough basement interface. The crystalline basement has a velocity of 4.5~5.5 km/s on the top, increasing to 6.8~6.9 km/s near the bottom of the crust. In the middle crust there is a small velocity discontinuity (0.1~0.2 km/s), while the Moho at the bottom of crust has a large velocity contrast (1.2 km/s). On the top mantle the velocity is 8.0~8.1 km/s. The Moho depth and the crustal thickness have much difference between the northern and southern segments along the line. The northern segment is in the deep sea basin, where the Moho is 11 km deep and the crystalline crust is only 5~6 km thick, which are typical characteristics of oceanic crust. In contrast, the southern segment is on the continental block, where the Moho has a maximum depth of 24 km and the crust has a corresponding thickness of 20 km, which are representative characteristics of thinned continental crust. From the deep sea basin to the continental block, the Moho depth and the crustal thickness increase rapidly. In the continental area, the upper crust and lower crust have similar thickness and variation. No High Velocity Layer (HVL) is seen in the lower crust. These may imply that pure-shear extension and uniform thinning are dominating inside the crust, and magma underplating is not developed in the lower crust. Comparing with the structure models of OBS973-2 and OBS973-3, it is inferred that the middle and eastern parts of Nansha Block have similar tectonic characters, and the two sides of Southwest Sub-basin are a pair of non-volcanic asymmetric conjugate continental margins. |
| |
| Keywords: | Southwest Sub-basin Nansha Block Ocean Bottom Seismometer (OBS) Crustal structure Conjugate continental margins |
| 本文献已被 万方数据 等数据库收录！ |
| 点击此处可从《地球物理学报》浏览原始摘要信息 |
| 点击此处可从《地球物理学报》下载免费的PDF全文 |
|
