南海西北海盆的构造特征及南海新生代的海底扩张
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摘要
分析了南海西北海盆及其邻区的地形地貌、重磁场异常和地壳结构特征，并对穿过西北海盆和中央海盆的地震剖面进行精细解释。结果发现，西北海盆的地球物理场异常、地质构造和地壳厚度均呈ＮＥ走向展布，而中央海盆则表现为ＥＷ向特征；西北海盆中的新生代沉积比中央海盆多一套地层（Ｔ４－Ｔｇ），说明西北海盆的年龄比中央海盆老。联系到南海西南海盆和西北海盆在区域构造、地球物理场异常和地形地貌特征等方面的相似，以及西南海盆和中央海盆由磁异常条带对比得出的年龄差异，我们认为，西北海盆和西南海盆是在第一次海底扩张时（４２－３５ＭａＢ．Ｐ．）形成的，中央海盆是在第二次海底扩张时形成的。
By analyzing the topography, landform, gravity anomalies, geomagneticanomalies and crustal structure, and interpreting the seismic profile across theNorthwest Subbasin and the Central Basin, it is found that the trends of geophysicalanomalies, geological structure and crustal isopach are to the northeast in theNorthwest Subbasin. and to the east in the Central Basin. The Northwest Subbasin hasone more set of strata (T4-Tg) than the Central Basin, which means that the age ofthe Northwest Subbasin is older than the Central Basin. According to the similaritiesin the regional structure, geophysical anomalies, topography and landform, and the agedifference between the Southwest Subbasin and the Central Basin acquired byinterpreting magnetic anomaly lineations, it is believed that the Northwest Subbasinand the Southwest Subbasin formed during the firet seafloor spreading between the lateEocene and the early Oligocene (42-35 million yrs. B. P.), and the Central Basinformed during the second seafloor spreading between the late Oligocene and the earlyMiocene (32-17 million yrs. B. P.).
By analyzing the topography, landform, gravity anomalies, geomagneticanomalies and crustal structure, and interpreting the seismic profile across theNorthwest Subbasin and the Central Basin, it is found that the trends of geophysicalanomalies, geological structure and crustal isopach are to the northeast in theNorthwest Subbasin. and to the east in the Central Basin. The Northwest Subbasin hasone more set of strata (T4-Tg) than the Central Basin, which means that the age ofthe Northwest Subbasin is older than the Central Basin. According to the similaritiesin the regional structure, geophysical anomalies, topography and landform, and the agedifference between the Southwest Subbasin and the Central Basin acquired byinterpreting magnetic anomaly lineations, it is believed that the Northwest Subbasinand the Southwest Subbasin formed during the firet seafloor spreading between the lateEocene and the early Oligocene (42-35 million yrs. B. P.), and the Central Basinformed during the second seafloor spreading between the late Oligocene and the earlyMiocene (32-17 million yrs. B. P.).
引文
1 Ludwig W J, Kumar N, Houtz R E. Profiler-sonobuoy measurement in the South China Sea Basin. J. G.K, 1979. 84: 3 505-3518
2 Yao Bochu , Wang Guangyu. Crustal structure of the South China Sea Basin. Scientia Sinica. 1983, 26(6) 6480-661
3鲍才旺。南海地形图。见:南海地质地球物理图集。广州:广东地图出版社, 1987
4薛万俊。南海地貌图。见:南海地质地球物理图集。广州:广东地图出版社, 1987
5 Taylor B, Hayes D E. Origin and history of the South China Sea Basin. In:Tectonic and geologic evolutionof southeast Asian seas and islands, part 2. American Geophysical Union Geophysical Monograph, 1980, 27:23-56
6 Briais A, Patriat P, Tapponier P. Updated interpretation of magnetic anomalies and seafloor spreading stagesin the South China Sea Implication for the Tertiary tectonics of Southeast Asia. J. G K, 1993, 98 6 299-6 328
7何廉声。南海大地构造图,见:南海地质地球物理图集。广州:广东地图出版社, 1987
8陈圣源,南海磁力异常图。见:南海地质地球物理图集。广州:广东地图出版社,1987
9吕文正。南海中央海盆条带磁异常特征及构造演化。海洋学报, 1987,9(1): 69-78
10姚伯初,曾维军。中美联合调研南海地质专报。武汉:中国地质大学出版社, 1994-1-204
11梁德华,李扬。南海宪北海山玄武岩中超铁镁岩包体。见:南海地质研究(第四期).武汉:中国地质大学出版 社,1991.122-133
12金庆焕主编。南海地质与油气资源。北京:地质出版社, 1989.1-417
13鲍才旺,薛万俊。南海的海槽与海沟。见:南海地质研究,第3期。武汉:中国地质大学出版社, 1991. 118-125
14李唐根。南海重力异常图。见:南海地质地球物理图集。广州:广东地图出版社, 1987
15姚伯初,何廉声。南海北部大陆边缘上的声呐浮标测量(一).海洋地质研究, 1982,2(3): 11-23
16 Houtz R. Ewing J. Upper crustal structure as a function of plate age, J. G. K, 1976, 81:2490-2498
17 Le Pichon, Bonin J. Plate Tectonics. Elsevier Scientific Publishing Company, 1973. 173-207
18姚伯初。中南-礼乐断裂的特征及其构造意义。见:南海地质研究(第7期).武汉:中国地质大学出版社, 1995 1-14
19姚伯初。南海海盆新生代的构造演化史。海洋地质与第四纪地质, 1996, 16(2):1-14
20 Wessmann G, Kudrass H, Hinz K Continuing rifting on the South China Margin. Geowissenschaften, 1996,14: 310-312
2 Yao Bochu , Wang Guangyu. Crustal structure of the South China Sea Basin. Scientia Sinica. 1983, 26(6) 6480-661
3鲍才旺。南海地形图。见:南海地质地球物理图集。广州:广东地图出版社, 1987
4薛万俊。南海地貌图。见:南海地质地球物理图集。广州:广东地图出版社, 1987
5 Taylor B, Hayes D E. Origin and history of the South China Sea Basin. In:Tectonic and geologic evolutionof southeast Asian seas and islands, part 2. American Geophysical Union Geophysical Monograph, 1980, 27:23-56
6 Briais A, Patriat P, Tapponier P. Updated interpretation of magnetic anomalies and seafloor spreading stagesin the South China Sea Implication for the Tertiary tectonics of Southeast Asia. J. G K, 1993, 98 6 299-6 328
7何廉声。南海大地构造图,见:南海地质地球物理图集。广州:广东地图出版社, 1987
8陈圣源,南海磁力异常图。见:南海地质地球物理图集。广州:广东地图出版社,1987
9吕文正。南海中央海盆条带磁异常特征及构造演化。海洋学报, 1987,9(1): 69-78
10姚伯初,曾维军。中美联合调研南海地质专报。武汉:中国地质大学出版社, 1994-1-204
11梁德华,李扬。南海宪北海山玄武岩中超铁镁岩包体。见:南海地质研究(第四期).武汉:中国地质大学出版 社,1991.122-133
12金庆焕主编。南海地质与油气资源。北京:地质出版社, 1989.1-417
13鲍才旺,薛万俊。南海的海槽与海沟。见:南海地质研究,第3期。武汉:中国地质大学出版社, 1991. 118-125
14李唐根。南海重力异常图。见:南海地质地球物理图集。广州:广东地图出版社, 1987
15姚伯初,何廉声。南海北部大陆边缘上的声呐浮标测量(一).海洋地质研究, 1982,2(3): 11-23
16 Houtz R. Ewing J. Upper crustal structure as a function of plate age, J. G. K, 1976, 81:2490-2498
17 Le Pichon, Bonin J. Plate Tectonics. Elsevier Scientific Publishing Company, 1973. 173-207
18姚伯初。中南-礼乐断裂的特征及其构造意义。见:南海地质研究(第7期).武汉:中国地质大学出版社, 1995 1-14
19姚伯初。南海海盆新生代的构造演化史。海洋地质与第四纪地质, 1996, 16(2):1-14
20 Wessmann G, Kudrass H, Hinz K Continuing rifting on the South China Margin. Geowissenschaften, 1996,14: 310-312
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