南海北部IODP U1499站位砾石层的古沉积环境及构造意义
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摘要
南海北部IODP 367航次深海钻遇砾石层,因前期地球物理资料预测不足,导致出现多种成因猜测.利用南海北部大量高精度地震、油气钻井和IODP资料,从构造地层学、层序地层学和沉积充填动力学等角度,恢复研究区砾石层沉积时的古地貌特征.研究结果表明,砾石层形成于晚始新世-早渐新世,发育于小型断陷陆相湖盆周缘,以近源三角洲相沉积为主,其物源主要来自湖盆周缘的东沙和礼乐中生代地层剥蚀区;砾石层的顶界面对应于T70与T60重合面,其中T70为南海北部海底渐进式扩张形成的破裂不整合面,年龄介于33.0～28.4 Ma,具有东早西晚的特征.此外,认为南海北部洋陆转换带的位置并非目前认为的3 000 m水深附近,而应该是水深更深的一系列小型箕状断陷的南部边缘.
Gravel layers were drilled at IODP 367 Site U1499 in northern South China Sea. A variety of possible genetic mechanism for gravel layers,which are incorrect or uncertain predictions from observations in geophysical data in advance, have been proposed through the lithostratigraphic units in the cored sediment at site U1499. Using tectonostratigraphy and sediment-filling dynamics, this study restores the paleo-geomorphology during the gravel layers sedimentation period based on a high-resolution seismic database and IODP site data from the northern margin of the South China Sea. The results indicate that the gravel layers should be deposited in proximal delta sedimentation environment along Late Eocene-Early Oligocene lacustrine basin peripheral, whose provenance is mainly from Mesozoic erosion areas of Dongsha and Liyue. The top of the gravel layers corresponds to a coincidence boundary of T70 and T60 in seismic profiles. T70 unconformity is likely directly related to the continental breakup during the initial opening of the northern South China Sea. T70 boundary age is estimated to be at 33.0–28.4 Ma and is earlier in the east than that of the west. Besides, this paper suggests that the position of ocean-continent transition zone may be near the southern edge of a series of small extensional half-grabens in the northern South China Sea rather than a geomorphic abrupt domain with a water depth of 3 000 m.
Gravel layers were drilled at IODP 367 Site U1499 in northern South China Sea. A variety of possible genetic mechanism for gravel layers,which are incorrect or uncertain predictions from observations in geophysical data in advance, have been proposed through the lithostratigraphic units in the cored sediment at site U1499. Using tectonostratigraphy and sediment-filling dynamics, this study restores the paleo-geomorphology during the gravel layers sedimentation period based on a high-resolution seismic database and IODP site data from the northern margin of the South China Sea. The results indicate that the gravel layers should be deposited in proximal delta sedimentation environment along Late Eocene-Early Oligocene lacustrine basin peripheral, whose provenance is mainly from Mesozoic erosion areas of Dongsha and Liyue. The top of the gravel layers corresponds to a coincidence boundary of T70 and T60 in seismic profiles. T70 unconformity is likely directly related to the continental breakup during the initial opening of the northern South China Sea. T70 boundary age is estimated to be at 33.0–28.4 Ma and is earlier in the east than that of the west. Besides, this paper suggests that the position of ocean-continent transition zone may be near the southern edge of a series of small extensional half-grabens in the northern South China Sea rather than a geomorphic abrupt domain with a water depth of 3 000 m.
引文
Ao,W.,Zhao,M.H.,Qiu,X.L.,et al.,2012.Crustal Structure of the Northwest Sub-Basin of the South China Sea and Its Tectonic Implication.Earth Science,37(4):779-790(in Chinese with English abstract).
Bai,Y.,Wu,S.,Liu,Z.,et al.,2015.Full-Fit Reconstruction of the South China Sea Conjugate Margins.Tectonophysics,661:121-135.
Barckhausen,U.,Engels,M.,Franke,D.,et al.,2014.Evolution of the South China Sea:Revised Ages for Breakup and Seafloor Spreading.Marine and Petroleum Geology,58(PartB):599-611.
Barckhausen,U.,Roeser,H.A.,2004.Seafloor Spreading Anomalies in the South China Sea Revisited.In Clift,P.,Wang,P.,Kuhnt,W.,et al.,eds.,Continent-Ocean Interactions within East Asian Marginal Seas.Geophysical Monograph,149:121-125.
Briais, A.,Patriat,P.,Tapponnier,P.,1993.Updated Interpretation of Magnetic Anomalies and Seafloor Spreading Stages in the South China Sea:Implications for the Tertiary Tectonics of Southeast Asia.Journal of Geophysical Research,98B:6299-6328.https://doi.org/10.1029/92JB02280
Cai,Z.R.,Liu,W.L.,Wan,Z.F.,et al.,2010.Determination of Cenozoic Tectonic Movement in the Northern South China Sea and the Relationship between Oil-Gas Reservoir and Tectonic Movement.Marine Science Bulletin,29(2):161-165(in Chinese with English abstract).
Cameselle,A.L.,Ranero,C.R.,Franke,D.,et al.,2015.The Continent-Ocean Transition on the Northwestern South China Sea.Geophysical Research Abstracts,16:EGU2014-14917.
Chen,F.,Lu,H.F.,Liu,J.,2016.Sedimentary Geochemical Response to Gas Hydrate Episodic Release on the Northeastern Slope of the South China Sea-Earth Science,41(10):1619-1629(in Chinese with English abstract).
Chen,L.,2014.Stretching Factor Estimation for the Long-Duration and Multi-stage Continental Extensional Tectonics:Application to the Baiyun Sag in the Northern Margin of the South China Sea. Tec to nop hysics,611:167-180.
Cullen,A.,Reemst,P.,Henstra,G.,et al.,2010.Rifting of the South China Sea:New Perspectives.Petroleum Geoscience,16:273-282.
Ding,W.W.,Li,M.B.,Zhao,L.H.,et al.,2009.Cenozoic Tectono-Sedimentary Characteristics and Extension Model of the North-West Sub-Basin,South China Sea.Earth Science Frontiers,16(4):147-156(in Chinese with English abstract).
Du,T.J.,2013.Sequence Stratigraphic and Deep Water Sedimentary Characteristic in the Qiongdongnan Basin(Dissertation).Ocean University of China,Qingdao, 19-82(in Chinese with English abstract).
Eagles,G.,Perez-Diaz,L.,Scarselli,N.,2015.Getting over Continent Ocean Boundaries.Earth Science Reviews,151:244-265.
Franke,D.,Savva,D.,Pubellier,M.,et al.,2014.The Final Rifting Evolution in the South China Sea.Marine Petroleum Geology,58:704-720.
Gao,J.W.,Wu,S.G.,McIntosh,K.,2015.The Continent-Ocean Transition at the Mid-Northern Margin of the South China Sea.Tectonophysics,654:1-19.
IODP Preliminary Report,2014.South China Sea Tectonics:Opening of the South China Sea and Its Implications for Southeast Asian Tectonics,Climates,and Deep Mantle Processes since the Late Mesozoic.International Ocean Discovery Program Preliminary Report,349.
Larsen,H.C.,Mohn,G.,Nirrengarten,M.,et al.,2018.Rapid Transition from Continental Breakup to Igneous Oceanic Crust in the South China Sea.Nature Geoscience,11:782-789.
Lei,C.,Ren,J.Y.,Zhang,J.,2015.Tectonic Province Divisions in the South China Sea:Implications for Basin Geodynamics.Earth Science,40(4):744-762(in Chinese with English abstract).
Li,C.F.,Li,J.,Ding,W.,et al.,2015a.Seismic Stratigraphy of the Central South China Sea Basin and Implications for Neotectonics.Journal of Geophysical Research:Solid Earth,120:1377-1399.
Li,C.F.,Lin,J.,Kulhanek,D.K.,et al.,2015b.Site U1435.In:Li,C.F.,Lin,J.,Kulhanek,D.K.,eds.,The Expedition 349 Scientists,South China Sea Tectonics.Proceedings of the International Ocean Discovery Program,349:College Station,TX, International Ocean Discovery Program. https://doi.org/10.14379/odp.proc.349.107.2015
Liu,X.Y.,Zhang,D.J.,Zuo,Q.M.,et al.,2013.The Research of Biostratigraphy in the Deepwater Area of Qiongdongnan Basin,North western South China Sea.Journal of Stratigraphy,37(4):571-572(in Chinese).
Mi,L.J.,Zhang,G.C.,Shen,H.L.,et al.,2008.Eocene-Lower Oligocene Sedimentation Characteristics of Baiyun Sag in the Deep Water Area of Pearl River Mouth Basin.Acta Petrolei Sinica,29(1):29-34(in Chinese with English abstract).
Qian,X.,Zhang,L.,Wu,S.G.,et al.,2017.Sedimentary Response to Tectonic Evolution of the Northwest Sub-Basin,South ChinaSea.Geotectonica et Metallogenia,42(2):248-257(in Chinese with English abstract).
Ren,J.Y.,Pang,X.,Lei,C.,et al.,2015.Ocean and Continent Transition in Passive Continental Margins and Analysis of Lithospheric Extension and Breakup Process:Implication for Research of the Deepwater Basins in the Continental Margins of South China Sea.Earth Science Frontiers,22(1):102-114(in Chinese with English abstract).
Sun,Z.,Stock,J.,Klaus,A.,et al.,2018. Expedition 367 Preliminary Report:South China Sea Rifted Margin.International Ocean Discovery Program. https://doi.org/10.14379/iodp.pr.367.2018
Sun,Z.,Liu,S.Q.,Pang,X.,et al.,2016.Recent Research Progress on the Rifting-Breakup Process in Passive Continental Margins Journal of Tropical Oceanography,35(1):1-16(in Chinese with English abstract).
Sun,Z.,Stock,J.,Jian,Z.,et al.,2016.Expedition 367/368 Scientific Prospectus:South China Sea Rifted Margin. International Ocean Discovery Program.https://doi.org/10.14379/iodp.sp.367368.2016
Wang,G.H.,Wang,H.,Gan,H.J.,et al.,2016.Paleogene Tectonic Evolution Controls on Sequence Stratigraphic Patterns in the Fushan Sag, Northern South China Sea.Journal of Earth Science,27(4):654-669.
Wang,T.,Chen,M.,Lee,C.,et al.,2006.Seismic Imaging of the Transitional Crust across the Northeastern Margin of the South China Sea.Tectonophysics,412:237-254.
Xie,X.N.,Ren,J.Y.,Wang,Z.F.,et al.,2015.Difference of Tectonic Evolution of Continental Marginal Basins of South China Sea and Relationship with SCS Spreading.Earth Science Frontiers,22(1):77-87(in Chinese with English abstract).
Zhang,G.C.,2010.Tectonic Evolution of Deepwater Area of Northern Continental Margin in South China Sea.Acta Petrolei Sinica,31(4):528-533(in Chinese with English abstract).
Zhang,G.C.,Wang,P.J.,Wu,J.F.,et al.,2015.Tectonic Cycle of Marginal Oceanic Basin:A New Evolution Model of the South China Sea.Earth Science Frontiers,22(3):27-37(in Chinese with English abstract).
Zhao,Z.,Zhao,Z.G.,Shen,H.L.,et al.,2016.Tectonic Evolution and Hydrocarbon Geological Conditions of Shuangfeng Basin in the Ultra-Deep Water Area of the Northern South China Sea.Acta Petrolei Sinica,37(Suppl.1):47-57(in Chinese with English abstract).
Zhou,D.,Yao,B.,2009.Tectonics and Sedimentary Basins of the South China Sea:Challenges and Progresses Journal of Earth Science,20:1-2.https://doi.org/10.1007/s 12583-009-0001-8
Zhu,J.J.,Qiu,X.L.,Xu,H.L.,et al.,2012.Seismic Reflection Characteristic and Structure Unit Division of an Ocean-Continent Transition Zone in the Northern South China Sea Journal of Tropical Oceanography,31(3):28-34(in Chinese with English abstract).
敖威,赵明辉,丘学林,等,2012.南海西北次海盆及其邻区地壳结构和构造意义.地球科学,3 7(4):779-790.
蔡周荣,刘维亮,万志峰,等,2010.南海北部新生代构造运动厘定及与油气成藏关系探讨.海洋通报,29(2):161-165.
陈芳,陆红锋,刘坚,2016.南海东北部陆坡天然气水合物多期次分解的沉积地球化学响应.地球科学,41(10):1619-1629.
丁巍伟,黎明碧,赵俐红,等,2009.南海西北次海盆新生代构造—沉积特征及伸展模式探讨.地学前缘,16(4):147-156.
杜同军,2013.琼东南盆地层序地层和深水区沉积充填特征(博士学位论文).青岛:中国海洋大学,19-82.
雷超,任建业,张静,2015.南海构造变形分区及成盆过程.地球科学,40(4):744-762.
刘新宇,张道军,左倩媚,等,2013.南海北部西区琼东南盆地深水区生物地层研究进展——以LS33-1-1井为例.地层学杂志,37(4):571-572.
米立军,张功成,沈怀磊,等,2008.珠江口盆地深水区白云凹陷始新统——下渐新统沉积特征.石油学报,29(1):29-34.
钱星,张莉,吴时国,等,2017.南海西北次海盆构造演化的沉积响应.大地构造与成矿学,42(2):248-257.
任建业,庞雄,雷超,等,2015.被动陆缘洋陆转换带和岩石圈伸展破裂过程分析及其对南海陆缘深水盆地研究的启示.地学前缘,22(1):102-114.
孙珍,刘思青,庞雄,等,2016.被动大陆边缘伸展——破裂过程研究进展.热带海洋学报,35(1):1-16.
解习农,任建业,王振峰,等,2015.南海大陆边缘盆地构造演化差异性及其与南海扩张耦合关系.地学前缘,22(1):77-87.
张功成,2010.南海北部陆坡深水区构造演化及其特征.石油学报,31(4):528-533.
张功成,王璞珺,吴景富,等,2015.边缘海构造旋回:南海演化的新模式.地学前缘,22(3):27-37.
赵钊,赵志刚,沈怀磊,等,2016.南海北部超深水区双峰盆地构造演化与油气地质条件.石油学报,37(增刊1):47-57.
朱俊江,丘学林,徐辉龙,等,2012.南海北部洋陆转换带地震反射特征和结构单元划分.热带海洋学报,31(3):28-34.
Bai,Y.,Wu,S.,Liu,Z.,et al.,2015.Full-Fit Reconstruction of the South China Sea Conjugate Margins.Tectonophysics,661:121-135.
Barckhausen,U.,Engels,M.,Franke,D.,et al.,2014.Evolution of the South China Sea:Revised Ages for Breakup and Seafloor Spreading.Marine and Petroleum Geology,58(PartB):599-611.
Barckhausen,U.,Roeser,H.A.,2004.Seafloor Spreading Anomalies in the South China Sea Revisited.In Clift,P.,Wang,P.,Kuhnt,W.,et al.,eds.,Continent-Ocean Interactions within East Asian Marginal Seas.Geophysical Monograph,149:121-125.
Briais, A.,Patriat,P.,Tapponnier,P.,1993.Updated Interpretation of Magnetic Anomalies and Seafloor Spreading Stages in the South China Sea:Implications for the Tertiary Tectonics of Southeast Asia.Journal of Geophysical Research,98B:6299-6328.https://doi.org/10.1029/92JB02280
Cai,Z.R.,Liu,W.L.,Wan,Z.F.,et al.,2010.Determination of Cenozoic Tectonic Movement in the Northern South China Sea and the Relationship between Oil-Gas Reservoir and Tectonic Movement.Marine Science Bulletin,29(2):161-165(in Chinese with English abstract).
Cameselle,A.L.,Ranero,C.R.,Franke,D.,et al.,2015.The Continent-Ocean Transition on the Northwestern South China Sea.Geophysical Research Abstracts,16:EGU2014-14917.
Chen,F.,Lu,H.F.,Liu,J.,2016.Sedimentary Geochemical Response to Gas Hydrate Episodic Release on the Northeastern Slope of the South China Sea-Earth Science,41(10):1619-1629(in Chinese with English abstract).
Chen,L.,2014.Stretching Factor Estimation for the Long-Duration and Multi-stage Continental Extensional Tectonics:Application to the Baiyun Sag in the Northern Margin of the South China Sea. Tec to nop hysics,611:167-180.
Cullen,A.,Reemst,P.,Henstra,G.,et al.,2010.Rifting of the South China Sea:New Perspectives.Petroleum Geoscience,16:273-282.
Ding,W.W.,Li,M.B.,Zhao,L.H.,et al.,2009.Cenozoic Tectono-Sedimentary Characteristics and Extension Model of the North-West Sub-Basin,South China Sea.Earth Science Frontiers,16(4):147-156(in Chinese with English abstract).
Du,T.J.,2013.Sequence Stratigraphic and Deep Water Sedimentary Characteristic in the Qiongdongnan Basin(Dissertation).Ocean University of China,Qingdao, 19-82(in Chinese with English abstract).
Eagles,G.,Perez-Diaz,L.,Scarselli,N.,2015.Getting over Continent Ocean Boundaries.Earth Science Reviews,151:244-265.
Franke,D.,Savva,D.,Pubellier,M.,et al.,2014.The Final Rifting Evolution in the South China Sea.Marine Petroleum Geology,58:704-720.
Gao,J.W.,Wu,S.G.,McIntosh,K.,2015.The Continent-Ocean Transition at the Mid-Northern Margin of the South China Sea.Tectonophysics,654:1-19.
IODP Preliminary Report,2014.South China Sea Tectonics:Opening of the South China Sea and Its Implications for Southeast Asian Tectonics,Climates,and Deep Mantle Processes since the Late Mesozoic.International Ocean Discovery Program Preliminary Report,349.
Larsen,H.C.,Mohn,G.,Nirrengarten,M.,et al.,2018.Rapid Transition from Continental Breakup to Igneous Oceanic Crust in the South China Sea.Nature Geoscience,11:782-789.
Lei,C.,Ren,J.Y.,Zhang,J.,2015.Tectonic Province Divisions in the South China Sea:Implications for Basin Geodynamics.Earth Science,40(4):744-762(in Chinese with English abstract).
Li,C.F.,Li,J.,Ding,W.,et al.,2015a.Seismic Stratigraphy of the Central South China Sea Basin and Implications for Neotectonics.Journal of Geophysical Research:Solid Earth,120:1377-1399.
Li,C.F.,Lin,J.,Kulhanek,D.K.,et al.,2015b.Site U1435.In:Li,C.F.,Lin,J.,Kulhanek,D.K.,eds.,The Expedition 349 Scientists,South China Sea Tectonics.Proceedings of the International Ocean Discovery Program,349:College Station,TX, International Ocean Discovery Program. https://doi.org/10.14379/odp.proc.349.107.2015
Liu,X.Y.,Zhang,D.J.,Zuo,Q.M.,et al.,2013.The Research of Biostratigraphy in the Deepwater Area of Qiongdongnan Basin,North western South China Sea.Journal of Stratigraphy,37(4):571-572(in Chinese).
Mi,L.J.,Zhang,G.C.,Shen,H.L.,et al.,2008.Eocene-Lower Oligocene Sedimentation Characteristics of Baiyun Sag in the Deep Water Area of Pearl River Mouth Basin.Acta Petrolei Sinica,29(1):29-34(in Chinese with English abstract).
Qian,X.,Zhang,L.,Wu,S.G.,et al.,2017.Sedimentary Response to Tectonic Evolution of the Northwest Sub-Basin,South ChinaSea.Geotectonica et Metallogenia,42(2):248-257(in Chinese with English abstract).
Ren,J.Y.,Pang,X.,Lei,C.,et al.,2015.Ocean and Continent Transition in Passive Continental Margins and Analysis of Lithospheric Extension and Breakup Process:Implication for Research of the Deepwater Basins in the Continental Margins of South China Sea.Earth Science Frontiers,22(1):102-114(in Chinese with English abstract).
Sun,Z.,Stock,J.,Klaus,A.,et al.,2018. Expedition 367 Preliminary Report:South China Sea Rifted Margin.International Ocean Discovery Program. https://doi.org/10.14379/iodp.pr.367.2018
Sun,Z.,Liu,S.Q.,Pang,X.,et al.,2016.Recent Research Progress on the Rifting-Breakup Process in Passive Continental Margins Journal of Tropical Oceanography,35(1):1-16(in Chinese with English abstract).
Sun,Z.,Stock,J.,Jian,Z.,et al.,2016.Expedition 367/368 Scientific Prospectus:South China Sea Rifted Margin. International Ocean Discovery Program.https://doi.org/10.14379/iodp.sp.367368.2016
Wang,G.H.,Wang,H.,Gan,H.J.,et al.,2016.Paleogene Tectonic Evolution Controls on Sequence Stratigraphic Patterns in the Fushan Sag, Northern South China Sea.Journal of Earth Science,27(4):654-669.
Wang,T.,Chen,M.,Lee,C.,et al.,2006.Seismic Imaging of the Transitional Crust across the Northeastern Margin of the South China Sea.Tectonophysics,412:237-254.
Xie,X.N.,Ren,J.Y.,Wang,Z.F.,et al.,2015.Difference of Tectonic Evolution of Continental Marginal Basins of South China Sea and Relationship with SCS Spreading.Earth Science Frontiers,22(1):77-87(in Chinese with English abstract).
Zhang,G.C.,2010.Tectonic Evolution of Deepwater Area of Northern Continental Margin in South China Sea.Acta Petrolei Sinica,31(4):528-533(in Chinese with English abstract).
Zhang,G.C.,Wang,P.J.,Wu,J.F.,et al.,2015.Tectonic Cycle of Marginal Oceanic Basin:A New Evolution Model of the South China Sea.Earth Science Frontiers,22(3):27-37(in Chinese with English abstract).
Zhao,Z.,Zhao,Z.G.,Shen,H.L.,et al.,2016.Tectonic Evolution and Hydrocarbon Geological Conditions of Shuangfeng Basin in the Ultra-Deep Water Area of the Northern South China Sea.Acta Petrolei Sinica,37(Suppl.1):47-57(in Chinese with English abstract).
Zhou,D.,Yao,B.,2009.Tectonics and Sedimentary Basins of the South China Sea:Challenges and Progresses Journal of Earth Science,20:1-2.https://doi.org/10.1007/s 12583-009-0001-8
Zhu,J.J.,Qiu,X.L.,Xu,H.L.,et al.,2012.Seismic Reflection Characteristic and Structure Unit Division of an Ocean-Continent Transition Zone in the Northern South China Sea Journal of Tropical Oceanography,31(3):28-34(in Chinese with English abstract).
敖威,赵明辉,丘学林,等,2012.南海西北次海盆及其邻区地壳结构和构造意义.地球科学,3 7(4):779-790.
蔡周荣,刘维亮,万志峰,等,2010.南海北部新生代构造运动厘定及与油气成藏关系探讨.海洋通报,29(2):161-165.
陈芳,陆红锋,刘坚,2016.南海东北部陆坡天然气水合物多期次分解的沉积地球化学响应.地球科学,41(10):1619-1629.
丁巍伟,黎明碧,赵俐红,等,2009.南海西北次海盆新生代构造—沉积特征及伸展模式探讨.地学前缘,16(4):147-156.
杜同军,2013.琼东南盆地层序地层和深水区沉积充填特征(博士学位论文).青岛:中国海洋大学,19-82.
雷超,任建业,张静,2015.南海构造变形分区及成盆过程.地球科学,40(4):744-762.
刘新宇,张道军,左倩媚,等,2013.南海北部西区琼东南盆地深水区生物地层研究进展——以LS33-1-1井为例.地层学杂志,37(4):571-572.
米立军,张功成,沈怀磊,等,2008.珠江口盆地深水区白云凹陷始新统——下渐新统沉积特征.石油学报,29(1):29-34.
钱星,张莉,吴时国,等,2017.南海西北次海盆构造演化的沉积响应.大地构造与成矿学,42(2):248-257.
任建业,庞雄,雷超,等,2015.被动陆缘洋陆转换带和岩石圈伸展破裂过程分析及其对南海陆缘深水盆地研究的启示.地学前缘,22(1):102-114.
孙珍,刘思青,庞雄,等,2016.被动大陆边缘伸展——破裂过程研究进展.热带海洋学报,35(1):1-16.
解习农,任建业,王振峰,等,2015.南海大陆边缘盆地构造演化差异性及其与南海扩张耦合关系.地学前缘,22(1):77-87.
张功成,2010.南海北部陆坡深水区构造演化及其特征.石油学报,31(4):528-533.
张功成,王璞珺,吴景富,等,2015.边缘海构造旋回:南海演化的新模式.地学前缘,22(3):27-37.
赵钊,赵志刚,沈怀磊,等,2016.南海北部超深水区双峰盆地构造演化与油气地质条件.石油学报,37(增刊1):47-57.
朱俊江,丘学林,徐辉龙,等,2012.南海北部洋陆转换带地震反射特征和结构单元划分.热带海洋学报,31(3):28-34.