南海大陆边缘动力学:科学实验与研究进展
|
摘要
国家重点基础研究发展计划(973)项目(2007CB411700)首次在南海南部大陆边缘及西南次海盆开展长排列大震源多道地震、海底地震仪(OBS)折射/反射地震等的综合地球物理探测,结合地质构造、地球化学、动力模拟等的综合研究,形成如下重要认识:南海海盆新生代发生了早、晚两期海底扩张.早期扩张发生于33.5～25 Ma,经过1.5 Ma的调整,晚期扩张发生于23.5～15.5 Ma.早晚两期扩张均为由东向西传播的渐进式扩张,构造上具有南北分块、东西分带的特点.南海新生代南、北陆缘沉积盆地从断陷到坳陷的构造转型时间存在差异,并分别与海盆晚期扩张和早期扩张的结束时间相对应.南海新生代陆缘张裂变形具有随深度变化的特点,海盆的洋壳深部和上地幔顶部存在磁化现象,地幔没有明显的速度异常.南北大陆边缘均属非火山型大陆边缘,虽然北部陆缘东段存在下地壳高速层,但没有发现向海反射层,而共轭对比应沿NW-SE向进行.南海新生代南北陆缘沉积盆地形成演化存在系统差异,总体上"外油内气"呈环带分布,南部陆缘盆地具有更优的油气成藏地质条件.南海中生代南北陆缘均为华南块体的一个部分,受到古特提斯和古太平洋构造域的联合控制.
Comprehensive geophysical survey,including the multi-channel seismic survey with long streamer and large air-gun source and the wide-angle refraction/reflection seismic survey of OBS,has been deployed in the southern margin and Southwest Sub-basin of the South China Sea for the first time.Based on the interpretation of these geophysical data,combined with studies on tectonic structure,geochemistry,and dynamic simulation,etc,our project worked out the dynamics of the continental margin in South China Sea.Major conclusions are as follows:Two sea-floor spreading events occurred in Cenozoic.The first episode happened between 33.5～25 Ma,and after a 1.5 Ma tectonic adjustment,started the second episode of sea-floor spreading between 23.5～15.5 Ma.In both episodes the South China Sea experienced propagation rifting and spreading from east to west,resulting in a structural framework featured with blocks in north-south direction and segments in east-west direction;Cenozoic marginal basins in the northern and southern continental margins show different rift-terminated time,which correspond with the two episodic sea-floor spreading respectively.The continental crust of the South China Sea might have experienced depth-dependent stretching.The lower crust and top of upper mantle have been magnetized and no obvious velocity anomalies of the mantle have been found in oceanic basin.South China Sea margins are a kind of magma-poor rifting,although lower crustal bodies of high-velocity occur in the east of the northern margin,but without SDR.The origin and evolution of sediment basins on northern and southern continental margins are very distinct,and the hydrocarbon accumulations are distributed in a cirque with oil outside and gas inside.We believe that the hydrocarbon-bearing perspectives in southern continental marginal basins are superior to these northern continental marginal basins.In Mesozoic the northern and southern margin of the South China Sea were parts of the South China Continental Block,which was controlled by the Tethays and Pacific tectonic domains.
Comprehensive geophysical survey,including the multi-channel seismic survey with long streamer and large air-gun source and the wide-angle refraction/reflection seismic survey of OBS,has been deployed in the southern margin and Southwest Sub-basin of the South China Sea for the first time.Based on the interpretation of these geophysical data,combined with studies on tectonic structure,geochemistry,and dynamic simulation,etc,our project worked out the dynamics of the continental margin in South China Sea.Major conclusions are as follows:Two sea-floor spreading events occurred in Cenozoic.The first episode happened between 33.5～25 Ma,and after a 1.5 Ma tectonic adjustment,started the second episode of sea-floor spreading between 23.5～15.5 Ma.In both episodes the South China Sea experienced propagation rifting and spreading from east to west,resulting in a structural framework featured with blocks in north-south direction and segments in east-west direction;Cenozoic marginal basins in the northern and southern continental margins show different rift-terminated time,which correspond with the two episodic sea-floor spreading respectively.The continental crust of the South China Sea might have experienced depth-dependent stretching.The lower crust and top of upper mantle have been magnetized and no obvious velocity anomalies of the mantle have been found in oceanic basin.South China Sea margins are a kind of magma-poor rifting,although lower crustal bodies of high-velocity occur in the east of the northern margin,but without SDR.The origin and evolution of sediment basins on northern and southern continental margins are very distinct,and the hydrocarbon accumulations are distributed in a cirque with oil outside and gas inside.We believe that the hydrocarbon-bearing perspectives in southern continental marginal basins are superior to these northern continental marginal basins.In Mesozoic the northern and southern margin of the South China Sea were parts of the South China Continental Block,which was controlled by the Tethays and Pacific tectonic domains.
引文
[1]黄忠贤,胥颐.南海及邻近地区的面波层析成像与S波速度结构.地球物理学报,2011,54(12):3089-3097,doi: 10.3969/j.issn.0001-5733.2011.12.010 Huang Z X,Xu Y.Tomography image of the surface wave and S wave velocity structure in the South China Sea and adjacent region.Chinese J.Geophys.(in Chinese),2011,54 (12):3089-3097,doi:10.3969/j.issn.0001-5733.2011. 12.010
[2]胥颐,郝天珧,李志伟等.中国边缘海域及其邻区的岩石层结构与构造分析.地学前缘,2008,15(3):55-63 Xu Y,Hao T Y,Li Z W,et al.Analysis of lithospheric structure andtectonicsoftheChinesemarginalseasand adjacent region.Earth Science Frontiers(in Chinese),2008, 15(3):55- 63
[3]李志伟,胥颐,郝天珧等.南海东北部及其邻近地区地壳上地幔P波速度结构.地学前缘,2009,16(4):252-260 Li Z W,Xu Y,Hao T Y,et al.P wave velocity structure in the crust and upper mantle beneath northeastern South China Sea and surrounding regions.Earth Science Frontiers(in Chinese),2009,16(4):252-260
[4]Li C F,Shi X B,Zhou Z Y,et al.Depths to the magnetic layer bottom in the South China Sea area and their tectonic implications.Geophysical Journal International,2010,182 (3):1229-1247
[5]卫小冬,阮爱国,赵明辉等.穿越东沙隆起和潮汕坳陷的OBS广角地震剖面.地球物理学报,2011,54(12):3325- 3335,doi:10.3969/j.issn.0001-5733.2011.12.030 Wei X D,Ruan A G,Zhao M H,et al.OBS wide-angle seismicprofile across the Dongsha Uplift and Chaoshan Depression.Chinese J.Geophys.(in Chinese),2011,54 (12):3325 - 3335,doi:10.3969/j.issn.0001-5733.2011. 12.030
[6]Yan P,Liu H L,Liu Z S.A crustal structure profile across the northern continental margin of the South China Sea. Tectonophysics,2001,338(1):1-21
[7]Qiu X L,Ye S Y,Wu S M,et al.Crustal structure across the Xisha Trough,northwestern South China Sea. Tectonophysics,2001,341(1-4):179-193
[8]宋海斌,郝天珧,江为为.南海北部张裂边缘的类型及其形成机制探讨.陈颙等主编,寸丹集(庆贺刘光鼎院士工作50周年学术论文集).北京:科学出版社,1998.74-81 Song H B,Hao T Y,Jiang W W.Discussion on type and formation mechanism of the northern margin of the South China Sea.In:ChenY,etal,eds.CundanAssembly. Beijing:Science Press,1998.74-81
[9]吴振利,李家彪,阮爱国等.南海西北次海盆地壳结构:海底广角地震实验结果.中国科学(D辑):地球科学,2011, 41(10):1463-1476 Wu Z L,Li J B,Ruan A G,et al.The crust structure of Northwestern Basin,South China Sea:Results from wideangle seismic profile.Science in China(Series D):Earth Science(in Chinese),2011,41(10):1463-1476
[10]郝天珧,黄松,徐亚等.南海东北部及邻区深部结构的综合地球物理研究.地球物理学报,2008,51(6):1785- 1796 Hao T Y,Huang S,XuY,et al.Comprehensive geophysical research on the deep structure of Northeastern South China Sea.Chinese J.Geophys.(in Chinese),2008, 51(6):1785- 1796
[11]Zhao M H,Qiu X L,Xia S H,et al.Seismic structure in the northeastern South China Sea:S-wave velocity and V_p/V_s ratios derived from three-component OBS data. Tectonophysics,2010,480(1-4):183-197
[12]丘学林,赵明辉,敖威等.南海西南次海盆与南沙地块的OBS探测和地壳结构.地球物理学报,2011,54(12):3117- 3128,doi:10.3969/j.issn.0001-5733.2011.12.012 Qiu X L,Zhao M H,Ao W,et al.OBS survey and crustal structure in the Southwest Sub Basin and Nansha area,South China Sea.Chinese J.Geophys.(in Chinese),2011,54 (12):3117-3128,doi:10.3969/j.issn.0001-5733.2011. 12.012
[13]阮爱国,牛雄伟,丘学林等.南海南部陆缘礼乐滩一条新的OBS广角地震剖面.地球物理学报,2011,54(12):3139- 3149,doi:10.3969/j.issn.0001-5733.2011.12.014 Ruan A G,Niu X W,Qiu X L,et al.A new wide-angle seismic profile crossing the Reed Bank,southern margin of the South China Sea.Chinese J.Geophys.(in Chinese), 2011,54(12):3139-3149,doi:10.3969/j.issn.0001-5733. 2011.12.014
[14]Wan S M,K(u|¨)erschner W M,Clift P D,et al.Extreme weathering/erosion during the Miocene climatic optimum: evidence from sediment record in the South China Sea. Geophysical Research Letters,2009,36:L19706,doi:10. 1029/2009GL040279
[15]Wan S M,Tian J,Steinke S,et al.Evolution and variability of the East Asian summer monsoon during the Pliocene: Evidence from clay mineral records of the South China Sea. Palaeogeography,Palaeoclimatology,Palaeoecology, 2010,293(1-2):237-247
[16]李安春,黄杰,蒋恒等.渐新世以来南海北部陆坡区沉积演化及其对构造的响应.地球物理学报,2011,54(12): 3233-3245,doi:10.3969/j.issn.0001-5733.2011.12.022 Li A C,Huang J,Jiang H,et al.Sedimentary evolution in the northern South China Sea Slope since Oligocene and its response to tectonics.Chinese J.Geophys.(in Chinese), 2011,54(12):3233-3245,doi:10.3969/j.issn.0001-5733. 2011.12.022
[17]解习农,张成,任建业等.南海南北大陆边缘盆地构造演化差异性对油气成藏条件控制.地球物理学报,2011,54 (12):3280-3291,doi:10.3969/j.issn.0001-5733.2011. 12.026 Xie X N,Zhang C,Ren J Y,et al.Effects of distinct tectonic evolutions on hysrocarbon accumulation in northern and southern continentalmarginal basinsof South China Sea. Chinese J.Geophys.(in Chinese),2011,54(12):3280- 3291,doi:10.3969/j.issn.0001-5733.2011.12.026
[18]李家彪,丁巍伟,高金耀等.南海新生代海底扩张的构造演化模式:来自高分辨率地球物理数据的新认识.地球物理学报,2011,54(12):3014-3025,doi:10.3969/j.issn.0001- 5733.2011.12.004 Li J B,Ding W W,Gao J Y,et al.Cenozoic tectonic evolution model of the sea-floor spreading in South China Sea:New constraints from high-resolution geophysical data. Chinese J.Geophys.(in Chinese),2011,54(12):3014- 3025,doi:10.3969/j.issn.0001-5733.2011.12.004
[19]丁巍伟,李家彪.南海南部陆缘构造变形特征及伸展作用:来自两条973多道地震测线的证据.地球物理学报,2011, 54(12):3038-3056,doi:10.3969/j.issn.0001-5733.2011. 12.006 Ding W W,Li J B.Seismic stratigraphy,tectonic structure and extension factors across the southern margin of the South China Sea:evidence from two regional multi-channel seismic profiles.Chinese J.Geophys.(in Chinese),2011,54(12): 3038-3056,doi:10.3969/j.issn.0001-5733.2011.12.006
[20]陈林,宋海斌,许鹤华等.张裂大陆边缘形成演化的数值模拟.地球物理学报,2009,52(11):2781-2787,doi:10. 3969/j.issn.0001-5733.2009.11.013 Chen L,Song H B,Xu H H,et al.The numerical modeling of the formation and evolution of rifted continental margin. Chinese J.Gepohys.(in Chinese),2009,52(11):2781- 2787,doi:10.3969/j.issn.0001-5733.2009.11.013
[21]Sun Z,Zhong Z H,Keep M,et al.3D analogue modeling of the South China Sea:A discussion on breakup pattern. Journal of Asian Earth Sciences,2009,34(4):544-556
[22]孙珍,赵中贤,李家彪等.南沙地块内破裂不整合与碰撞事件的构造分析.地球物理学报,2011,54(12):3220- 3233,doi:10.3969/j.issn.0001-5733.2011.12.021 Sun Z,Zhao Z X,Li J B,et al.Tectonic analysis of the Breakup and Collision Unconformities in the Nansha-Dangerous Ground.Chinese J.Geophys.(in Chinese), 2011,54(12):3220-3233,doi:10.3969/j.issn.0001- 5733.2011.12.021
[23]Li C F,Zhou Z Y,Hao H J,et al.Late Mesozoic tectonic structure and evolution along the present-day northeastern South China Sea continental margin.Journal of Asian Earth Sciences,2008,31(4-6):546-561
[2]胥颐,郝天珧,李志伟等.中国边缘海域及其邻区的岩石层结构与构造分析.地学前缘,2008,15(3):55-63 Xu Y,Hao T Y,Li Z W,et al.Analysis of lithospheric structure andtectonicsoftheChinesemarginalseasand adjacent region.Earth Science Frontiers(in Chinese),2008, 15(3):55- 63
[3]李志伟,胥颐,郝天珧等.南海东北部及其邻近地区地壳上地幔P波速度结构.地学前缘,2009,16(4):252-260 Li Z W,Xu Y,Hao T Y,et al.P wave velocity structure in the crust and upper mantle beneath northeastern South China Sea and surrounding regions.Earth Science Frontiers(in Chinese),2009,16(4):252-260
[4]Li C F,Shi X B,Zhou Z Y,et al.Depths to the magnetic layer bottom in the South China Sea area and their tectonic implications.Geophysical Journal International,2010,182 (3):1229-1247
[5]卫小冬,阮爱国,赵明辉等.穿越东沙隆起和潮汕坳陷的OBS广角地震剖面.地球物理学报,2011,54(12):3325- 3335,doi:10.3969/j.issn.0001-5733.2011.12.030 Wei X D,Ruan A G,Zhao M H,et al.OBS wide-angle seismicprofile across the Dongsha Uplift and Chaoshan Depression.Chinese J.Geophys.(in Chinese),2011,54 (12):3325 - 3335,doi:10.3969/j.issn.0001-5733.2011. 12.030
[6]Yan P,Liu H L,Liu Z S.A crustal structure profile across the northern continental margin of the South China Sea. Tectonophysics,2001,338(1):1-21
[7]Qiu X L,Ye S Y,Wu S M,et al.Crustal structure across the Xisha Trough,northwestern South China Sea. Tectonophysics,2001,341(1-4):179-193
[8]宋海斌,郝天珧,江为为.南海北部张裂边缘的类型及其形成机制探讨.陈颙等主编,寸丹集(庆贺刘光鼎院士工作50周年学术论文集).北京:科学出版社,1998.74-81 Song H B,Hao T Y,Jiang W W.Discussion on type and formation mechanism of the northern margin of the South China Sea.In:ChenY,etal,eds.CundanAssembly. Beijing:Science Press,1998.74-81
[9]吴振利,李家彪,阮爱国等.南海西北次海盆地壳结构:海底广角地震实验结果.中国科学(D辑):地球科学,2011, 41(10):1463-1476 Wu Z L,Li J B,Ruan A G,et al.The crust structure of Northwestern Basin,South China Sea:Results from wideangle seismic profile.Science in China(Series D):Earth Science(in Chinese),2011,41(10):1463-1476
[10]郝天珧,黄松,徐亚等.南海东北部及邻区深部结构的综合地球物理研究.地球物理学报,2008,51(6):1785- 1796 Hao T Y,Huang S,XuY,et al.Comprehensive geophysical research on the deep structure of Northeastern South China Sea.Chinese J.Geophys.(in Chinese),2008, 51(6):1785- 1796
[11]Zhao M H,Qiu X L,Xia S H,et al.Seismic structure in the northeastern South China Sea:S-wave velocity and V_p/V_s ratios derived from three-component OBS data. Tectonophysics,2010,480(1-4):183-197
[12]丘学林,赵明辉,敖威等.南海西南次海盆与南沙地块的OBS探测和地壳结构.地球物理学报,2011,54(12):3117- 3128,doi:10.3969/j.issn.0001-5733.2011.12.012 Qiu X L,Zhao M H,Ao W,et al.OBS survey and crustal structure in the Southwest Sub Basin and Nansha area,South China Sea.Chinese J.Geophys.(in Chinese),2011,54 (12):3117-3128,doi:10.3969/j.issn.0001-5733.2011. 12.012
[13]阮爱国,牛雄伟,丘学林等.南海南部陆缘礼乐滩一条新的OBS广角地震剖面.地球物理学报,2011,54(12):3139- 3149,doi:10.3969/j.issn.0001-5733.2011.12.014 Ruan A G,Niu X W,Qiu X L,et al.A new wide-angle seismic profile crossing the Reed Bank,southern margin of the South China Sea.Chinese J.Geophys.(in Chinese), 2011,54(12):3139-3149,doi:10.3969/j.issn.0001-5733. 2011.12.014
[14]Wan S M,K(u|¨)erschner W M,Clift P D,et al.Extreme weathering/erosion during the Miocene climatic optimum: evidence from sediment record in the South China Sea. Geophysical Research Letters,2009,36:L19706,doi:10. 1029/2009GL040279
[15]Wan S M,Tian J,Steinke S,et al.Evolution and variability of the East Asian summer monsoon during the Pliocene: Evidence from clay mineral records of the South China Sea. Palaeogeography,Palaeoclimatology,Palaeoecology, 2010,293(1-2):237-247
[16]李安春,黄杰,蒋恒等.渐新世以来南海北部陆坡区沉积演化及其对构造的响应.地球物理学报,2011,54(12): 3233-3245,doi:10.3969/j.issn.0001-5733.2011.12.022 Li A C,Huang J,Jiang H,et al.Sedimentary evolution in the northern South China Sea Slope since Oligocene and its response to tectonics.Chinese J.Geophys.(in Chinese), 2011,54(12):3233-3245,doi:10.3969/j.issn.0001-5733. 2011.12.022
[17]解习农,张成,任建业等.南海南北大陆边缘盆地构造演化差异性对油气成藏条件控制.地球物理学报,2011,54 (12):3280-3291,doi:10.3969/j.issn.0001-5733.2011. 12.026 Xie X N,Zhang C,Ren J Y,et al.Effects of distinct tectonic evolutions on hysrocarbon accumulation in northern and southern continentalmarginal basinsof South China Sea. Chinese J.Geophys.(in Chinese),2011,54(12):3280- 3291,doi:10.3969/j.issn.0001-5733.2011.12.026
[18]李家彪,丁巍伟,高金耀等.南海新生代海底扩张的构造演化模式:来自高分辨率地球物理数据的新认识.地球物理学报,2011,54(12):3014-3025,doi:10.3969/j.issn.0001- 5733.2011.12.004 Li J B,Ding W W,Gao J Y,et al.Cenozoic tectonic evolution model of the sea-floor spreading in South China Sea:New constraints from high-resolution geophysical data. Chinese J.Geophys.(in Chinese),2011,54(12):3014- 3025,doi:10.3969/j.issn.0001-5733.2011.12.004
[19]丁巍伟,李家彪.南海南部陆缘构造变形特征及伸展作用:来自两条973多道地震测线的证据.地球物理学报,2011, 54(12):3038-3056,doi:10.3969/j.issn.0001-5733.2011. 12.006 Ding W W,Li J B.Seismic stratigraphy,tectonic structure and extension factors across the southern margin of the South China Sea:evidence from two regional multi-channel seismic profiles.Chinese J.Geophys.(in Chinese),2011,54(12): 3038-3056,doi:10.3969/j.issn.0001-5733.2011.12.006
[20]陈林,宋海斌,许鹤华等.张裂大陆边缘形成演化的数值模拟.地球物理学报,2009,52(11):2781-2787,doi:10. 3969/j.issn.0001-5733.2009.11.013 Chen L,Song H B,Xu H H,et al.The numerical modeling of the formation and evolution of rifted continental margin. Chinese J.Gepohys.(in Chinese),2009,52(11):2781- 2787,doi:10.3969/j.issn.0001-5733.2009.11.013
[21]Sun Z,Zhong Z H,Keep M,et al.3D analogue modeling of the South China Sea:A discussion on breakup pattern. Journal of Asian Earth Sciences,2009,34(4):544-556
[22]孙珍,赵中贤,李家彪等.南沙地块内破裂不整合与碰撞事件的构造分析.地球物理学报,2011,54(12):3220- 3233,doi:10.3969/j.issn.0001-5733.2011.12.021 Sun Z,Zhao Z X,Li J B,et al.Tectonic analysis of the Breakup and Collision Unconformities in the Nansha-Dangerous Ground.Chinese J.Geophys.(in Chinese), 2011,54(12):3220-3233,doi:10.3969/j.issn.0001- 5733.2011.12.021
[23]Li C F,Zhou Z Y,Hao H J,et al.Late Mesozoic tectonic structure and evolution along the present-day northeastern South China Sea continental margin.Journal of Asian Earth Sciences,2008,31(4-6):546-561
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心