南海西南次海盆北缘海底地震仪测线深部地壳结构研究
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摘要
基于2009年和2011年采集的海底地震仪数据,辅以多道地震数据,对南海西南次海盆北缘的地壳结构进行了探索.利用二维射线追踪的反演方法建立测线上的模型.利用声学基底面的反射波,下地壳顶界面的反射波和莫霍面的反射波走时的反演勾绘了地层中的不连续界面,利用自声学基底面下的折射波和来自上地幔的首波来反演整条测线的P波速度结构.结果发现在下地壳顶界面和莫霍面都出现了较大的起伏,据此推断西南次海盆的张裂模式,并得到西南次海盆与非火山型的大陆边缘伊比利亚-纽芬兰的张裂具有一定程度上的相似性的结论.说明了大陆张裂的两种端元力学模型不能很好的解释西南次海盆的拉张模式,而应用弹性梁的力学模型可以解释这种拉张模式.虽然在西南次海盆北部陆坡区的下地壳中没有发现大规模的岩浆活动,但是得出在莫霍界面上方可能有小规模熔融物质存在的结论.
Based on the OBS data and the multi-channel seismic data collected in 2009 and 2011, the structure of crust in the north part of Southwest Sub-basin in the South China Sea is explored.Using two-dimensional ray tracing method to establish P velocity model,employing acoustic basement reflection,the reflections from the top interface of lower crust and the Moho are calculated in order to give the location of the velocity discontinuity interfaces.By employing refraction under the acoustic basement and the head wave from the mantle,the P wave velocity structure of the entire survey line is pictured.The results showed that the depths of the top interface of lower crust and the Moho vary significantly.We inferred the southwest sub-basin rifting model,and concluded that there is a similarity in geological structure between the southwest sub basin of South China Sea and Iberia Newfoundland which is a typical non-volcanic margin.It is found that the two end-member mechanical continental rifting models could not satisfactorily explain the southwest sub-basin geological structure,while the elastic beam mechanics model can explain this rifting mode.Although in the lower crust of the northern part of southwest sub-basin there isn't large-scale magmatie activity,we inferred that a small amount of molten material may exist on the top of Moho.
Based on the OBS data and the multi-channel seismic data collected in 2009 and 2011, the structure of crust in the north part of Southwest Sub-basin in the South China Sea is explored.Using two-dimensional ray tracing method to establish P velocity model,employing acoustic basement reflection,the reflections from the top interface of lower crust and the Moho are calculated in order to give the location of the velocity discontinuity interfaces.By employing refraction under the acoustic basement and the head wave from the mantle,the P wave velocity structure of the entire survey line is pictured.The results showed that the depths of the top interface of lower crust and the Moho vary significantly.We inferred the southwest sub-basin rifting model,and concluded that there is a similarity in geological structure between the southwest sub basin of South China Sea and Iberia Newfoundland which is a typical non-volcanic margin.It is found that the two end-member mechanical continental rifting models could not satisfactorily explain the southwest sub-basin geological structure,while the elastic beam mechanics model can explain this rifting mode.Although in the lower crust of the northern part of southwest sub-basin there isn't large-scale magmatie activity,we inferred that a small amount of molten material may exist on the top of Moho.
引文
[1]Zhang Z M,Liou J G,Coleman R G.An outline of the plate tectonics of China.Geological Society of America Bulletin, 1984,95(3):295-312
[2]刘光鼎.中国海区及邻域地质地球物理系列图集.北京:地质出版社,1992 Liu G D.Geophysical Series Maps in China Sea and Adjacent Regions(in Chinese).Beijing:Science Press,1992
[3]Taylor B,Hayes D E.The tectonic evolution of the South China Basin.In:Hayes D E,ed.The Tectonic and Geologic Evolution of Southeast Asian Seas and Islands,1980,23; 89-104
[4]Hayes D E,Nissen S S,Buhl P,et al.Throughgoing crustal faults along the northern margin of the South China Sea and their role in crustal extension.J.Geophys.Res.,1995,100 (B11):22435-22446
[5]Nissen S S,Hayes D E,Bochu Y,et al.Gravity,heat flow, and seismic constraints on the processes of crustal extension: Northern margin of the South China Sea.J.Geophys.Res., 1995,100(B11):22447-22483
[6]Nissen S S,Hayes D E,Buhl P,et al.Deep penetration seismic soundings across the northern margin of the South China Sea.J.Geophys.Res.,1995,100(B11):22407- 22433
[7]Hayes D E.Margins of the Southwest sub-basin of the South China Sea—A frontier exploration target? Energy,1985,10 (3-4):373-382
[8]李家彪.中国边缘海形成演化与资源效应.北京:海洋出版社,2005 Li J B.Evolution and Resources Effect of Marginal Basins in the China Sea(in Chinese).Beijing:Ocean Press,2005
[9]Taylor B,Hayes D E.Origin and history of the South China Sea basin.In:Hayes D E,ed.The Tectonic and Geologic Evolution of Southeast Asian Seas and Islands,Part,1983, 2:23-56
[10]Ludwig W J,Kumar N,Houtz R E.Profiler-sonobuoy measurements in the South China Sea basin.J.Geophys. Res.,1979,84(B7):3505-3518
[11]Wang T K,Chen M K,Lee C S,et al.Seismic imaging of the transitional crust across the northeastern margin of the South China Sea.Tectonophysics,2006,412(3-4):237- 254
[12]Yan P,Zhou D,Liu Z S.A crustal structure profile across the northern continental margin of the South China Sea. Tectonophysics,2001,338(1):1-21
[13]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
[14]Hayes D E,Nissen S S.The South Chinasea margins: Implications for rifting contrasts.Earth and Planetary Science Letters,2005,237(3-4):601-616.
[15]赵明辉,丘学林,叶春明等.南海东北部海陆深地震联测与滨海断裂带两侧地壳结构分析.地球物理学报,2004,47 (5):845-852 Zhao M H,Qiu XL,Ye C M,et al.Analysis on deep crustal structure along the onshore-offshore seismic profile across the Binhai(littoral) fault zone in northeastern South China Sea. Chinese J.Geophys.(in Chinese),2004,47(5):845-852
[16]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,Xu Y,et al.Comprehensive geophysical research on the deep structure of Northeastern South China Sea.Chinese J.Geophys.(in Chinese),2009,52(6):1785- 1796
[17]郝天珧,徐亚,赵百民.南海磁性基底分布特征的地球物理研究.地球物理学报,2009,52(11):2763-2774 HaoT Y,Xu Y,Zhao B M,et al.Geophysical research on distribution features of magnetic basements in the South China Sea.Chinese J.Geophys.(in Chinese),2009,52(11): 2763-2774
[18]胡卫剑,江为为,朱东英.综合地球物理方法对南海西北部-印支半岛地区中生界分布的研究.地球物理学进展,2009, 24(2):522-529 Hu W J,Jiang W W,Zhu D Y.A study on distribution of Mesozoic strata in Northwestern South China Sea and Indo-China Peninsula using integrated geophysical methods. Progress in Geophys.(in Chinese),2009,24(2):522-529
[19]Zelt C A,Sain K,Naumenko J V,et al.Assessment of crustal velocity models using seismic refraction and reflection tomography.Geophysical Journal International,2003,153 (3):609-626
[20]Smith W H F,Sandwell D T.Global sea floor topography from satellite altimetry and ship depth soundings.Science, 1997,277(5334):1956-1962
[21]ChristesonG L,Mcintosh K D,Shipley T H,et al. Structure of the Costa Rica convergent margin,offshore Nicoya Peninsula.J.Geophys.Res.,1999,104(B11): 25443-25468
[22]Nakamura Y,Donoho P L,Roper P H,et al.Large-offset seismic surveying using ocean-bottom seismographs and air guns:instrumentation and field technique.Geophysics, 1987,52(12):1601
[23]Zelt C A,Smith R B.Seismic traveltime inversion for 2-D crustal velocity structure.Geophysical Journal International, 1992,108(1):16-34
[24]McKenzie D.Some remarks on the development of sedimentary basins.Earth and PlanetaryScience Letters, 1978,40(1):25-32
[25]Wernicke B.Low-angle normal faults in the Basin and Range Province:nappe tectonics in an extending orogen.Nature, 1981,291(5817):645-648
[26]Wernicke B,Axen G J.On the role of isostasy in the evolution of normal fault systems.Geology,1988,16(9): 848-851
[27]Mutter J C,Talwani M,Stoffa P L.Origin ofseaward-dipping reflectors in oceanic crust off the Norwegian margin by "subaerial sea-floor spreading".Geology,1982,10(7): 353-357
[28]Lister G S,Etheridge M A,Symonds P A.Detachment faulting andthe evolution of passive continental margins. Geology,1986,14(3):246-250
[29]Kusznir N J,Ziegler PA.Themechanics of continental extension and sedimentary basin formation:A simple-shear/ pure-shear flexural cantilever model.Tectonophysics,1992, 215(1-2):117-131
[30]Kusznir N J,Marsden G,Egan S S.A flexural-cantilever simple-shear/pure-shear model of continental lithosphere extension:applications to the Jeanne d'Arc Basin,Grand Banks and Viking Graben,North Sea.Geological Society, London,Special Publications,1991,56(1):41-60
[31]Whitmarsh R B,Wallace P J.The rift-to-drift development of the west Iberia nonvolcanic continental margin:a summary and review of the contribution of Ocean Drilling Program Leg 173.College Station,TX.2001
[32]Tucholke B E,Lin J.A geological model for the structure of ridge segments in slow spreading ocean crust.J.Geophys. Res.,1994,99(B6):11937-11958
[2]刘光鼎.中国海区及邻域地质地球物理系列图集.北京:地质出版社,1992 Liu G D.Geophysical Series Maps in China Sea and Adjacent Regions(in Chinese).Beijing:Science Press,1992
[3]Taylor B,Hayes D E.The tectonic evolution of the South China Basin.In:Hayes D E,ed.The Tectonic and Geologic Evolution of Southeast Asian Seas and Islands,1980,23; 89-104
[4]Hayes D E,Nissen S S,Buhl P,et al.Throughgoing crustal faults along the northern margin of the South China Sea and their role in crustal extension.J.Geophys.Res.,1995,100 (B11):22435-22446
[5]Nissen S S,Hayes D E,Bochu Y,et al.Gravity,heat flow, and seismic constraints on the processes of crustal extension: Northern margin of the South China Sea.J.Geophys.Res., 1995,100(B11):22447-22483
[6]Nissen S S,Hayes D E,Buhl P,et al.Deep penetration seismic soundings across the northern margin of the South China Sea.J.Geophys.Res.,1995,100(B11):22407- 22433
[7]Hayes D E.Margins of the Southwest sub-basin of the South China Sea—A frontier exploration target? Energy,1985,10 (3-4):373-382
[8]李家彪.中国边缘海形成演化与资源效应.北京:海洋出版社,2005 Li J B.Evolution and Resources Effect of Marginal Basins in the China Sea(in Chinese).Beijing:Ocean Press,2005
[9]Taylor B,Hayes D E.Origin and history of the South China Sea basin.In:Hayes D E,ed.The Tectonic and Geologic Evolution of Southeast Asian Seas and Islands,Part,1983, 2:23-56
[10]Ludwig W J,Kumar N,Houtz R E.Profiler-sonobuoy measurements in the South China Sea basin.J.Geophys. Res.,1979,84(B7):3505-3518
[11]Wang T K,Chen M K,Lee C S,et al.Seismic imaging of the transitional crust across the northeastern margin of the South China Sea.Tectonophysics,2006,412(3-4):237- 254
[12]Yan P,Zhou D,Liu Z S.A crustal structure profile across the northern continental margin of the South China Sea. Tectonophysics,2001,338(1):1-21
[13]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
[14]Hayes D E,Nissen S S.The South Chinasea margins: Implications for rifting contrasts.Earth and Planetary Science Letters,2005,237(3-4):601-616.
[15]赵明辉,丘学林,叶春明等.南海东北部海陆深地震联测与滨海断裂带两侧地壳结构分析.地球物理学报,2004,47 (5):845-852 Zhao M H,Qiu XL,Ye C M,et al.Analysis on deep crustal structure along the onshore-offshore seismic profile across the Binhai(littoral) fault zone in northeastern South China Sea. Chinese J.Geophys.(in Chinese),2004,47(5):845-852
[16]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,Xu Y,et al.Comprehensive geophysical research on the deep structure of Northeastern South China Sea.Chinese J.Geophys.(in Chinese),2009,52(6):1785- 1796
[17]郝天珧,徐亚,赵百民.南海磁性基底分布特征的地球物理研究.地球物理学报,2009,52(11):2763-2774 HaoT Y,Xu Y,Zhao B M,et al.Geophysical research on distribution features of magnetic basements in the South China Sea.Chinese J.Geophys.(in Chinese),2009,52(11): 2763-2774
[18]胡卫剑,江为为,朱东英.综合地球物理方法对南海西北部-印支半岛地区中生界分布的研究.地球物理学进展,2009, 24(2):522-529 Hu W J,Jiang W W,Zhu D Y.A study on distribution of Mesozoic strata in Northwestern South China Sea and Indo-China Peninsula using integrated geophysical methods. Progress in Geophys.(in Chinese),2009,24(2):522-529
[19]Zelt C A,Sain K,Naumenko J V,et al.Assessment of crustal velocity models using seismic refraction and reflection tomography.Geophysical Journal International,2003,153 (3):609-626
[20]Smith W H F,Sandwell D T.Global sea floor topography from satellite altimetry and ship depth soundings.Science, 1997,277(5334):1956-1962
[21]ChristesonG L,Mcintosh K D,Shipley T H,et al. Structure of the Costa Rica convergent margin,offshore Nicoya Peninsula.J.Geophys.Res.,1999,104(B11): 25443-25468
[22]Nakamura Y,Donoho P L,Roper P H,et al.Large-offset seismic surveying using ocean-bottom seismographs and air guns:instrumentation and field technique.Geophysics, 1987,52(12):1601
[23]Zelt C A,Smith R B.Seismic traveltime inversion for 2-D crustal velocity structure.Geophysical Journal International, 1992,108(1):16-34
[24]McKenzie D.Some remarks on the development of sedimentary basins.Earth and PlanetaryScience Letters, 1978,40(1):25-32
[25]Wernicke B.Low-angle normal faults in the Basin and Range Province:nappe tectonics in an extending orogen.Nature, 1981,291(5817):645-648
[26]Wernicke B,Axen G J.On the role of isostasy in the evolution of normal fault systems.Geology,1988,16(9): 848-851
[27]Mutter J C,Talwani M,Stoffa P L.Origin ofseaward-dipping reflectors in oceanic crust off the Norwegian margin by "subaerial sea-floor spreading".Geology,1982,10(7): 353-357
[28]Lister G S,Etheridge M A,Symonds P A.Detachment faulting andthe evolution of passive continental margins. Geology,1986,14(3):246-250
[29]Kusznir N J,Ziegler PA.Themechanics of continental extension and sedimentary basin formation:A simple-shear/ pure-shear flexural cantilever model.Tectonophysics,1992, 215(1-2):117-131
[30]Kusznir N J,Marsden G,Egan S S.A flexural-cantilever simple-shear/pure-shear model of continental lithosphere extension:applications to the Jeanne d'Arc Basin,Grand Banks and Viking Graben,North Sea.Geological Society, London,Special Publications,1991,56(1):41-60
[31]Whitmarsh R B,Wallace P J.The rift-to-drift development of the west Iberia nonvolcanic continental margin:a summary and review of the contribution of Ocean Drilling Program Leg 173.College Station,TX.2001
[32]Tucholke B E,Lin J.A geological model for the structure of ridge segments in slow spreading ocean crust.J.Geophys. Res.,1994,99(B6):11937-11958
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