Rift Evolution and Magmatic-Tectonic-Stratigraphic Records of Episodic Seafloor Spreading at Southwest Sub-Basin of South China Sea
-
摘要: 目前对于边缘海背景下被动大陆边缘的形成演化机制仍存在争议，特别是对洋陆转换带的构造特征与形成过程的认识存在明显不足.为了深入探索边缘海背景下南海陆缘与洋陆转换带构造结构与形成演化特征，通过对横跨西南次海盆Ⅴ型尖端地震剖面的解释与研究，识别出莫霍面（Moho）、基底和海底3个一级陆缘界面，划分出细颈化域、超伸展域、原洋域等构造单元；进一步精细解释了共轭陆缘盆地充填层序和多期断裂系统，识别出破裂不整合界面Bi，将陆缘盆地同裂陷期层序（Tg-Bi）划分为S1-S5五个层序，建立了西南次海盆Ⅴ型尖端区域共轭陆缘的构造‒地层格架.构造‒地层格架中S3/S4层序之间的界面CBi、S4/S5之间的界面POBi分别与陆壳破裂和原洋洋壳Ⅰ的破裂对应，记录了西南次海盆共轭陆缘岩石圈伸展破裂过程中发生的重要构造事件.结合断裂活动性和盆地原型的分析，将西南次海盆共轭陆缘同裂陷期的演化划分为伸展、细颈化、超伸展和原洋洋壳四个阶段，建立了西南次海盆共轭陆缘演化模式.还建立了西南次海盆Ⅴ型尖端共轭陆缘地壳的“鳄鱼嘴”结构，识别出总宽度达231 km的两期原洋洋壳.结合外缘高地和同破裂层序（S4-S5）研究，提出两期原洋洋壳的发育与西南次海盆的两幕扩张过程相对应，由原洋洋壳构成了同期洋盆的洋陆转换带.揭示了西南次海盆张开过程中岩石圈的伸展破裂机制与洋脊传播过程中幕式扩张作用对陆缘构造、地层和岩浆作用的影响，对于深入研究南海岩石圈的伸展破裂过程、洋陆转换带的成因以及南海被动陆缘形成的动力学机制具有重要意义.Abstract: The formation and evolution mechanism of the passive rift margin under the marginal sea background is still controversial, especially existing studies on the structural characteristics and formation process of the oceanic and continental transition zone are insufficient. In order to deeply explore the tectonic structure and evolution characteristics of the rift margin and oceanic transition zone of the South China Sea (SCS) under the background of marginal sea, this study presents an investigation of the seismic profiles across the Ⅴ-shaped tip of the Southwest Sub-basin of the SCS, identifying three first order rift margin interfaces including the Moho, Top of basement, and seafloor. The tectonic units of the conjugate margin are subdivided into the necking domain, the hyper-extended domain, and the proto-oceanic domain. The study further refines the interpretation of the stratigraphic sequences and multi-phase fault systems at the conjugate margin as well as identifies the breakup unconformity surface Bi. We divide the syn-rift sequence (between Tg and Bi) into five sequence units (S1-S5), establishing a tectono-stratigraphic framework for the conjugate margin of the SW sub-basin of the SCS. The study indicates that the interface CBi between S3 and S4, as well as the interface POBi between S4 and S5, corresponds to the break-up of continental crust and proto-oceanic crustⅠ, respectively, recording important tectonic events during the rifting. Based on the analysis of fault activity and basin prototyping, we divide the evolution of the conjugate margin into four stages: stretching, necking, hyper-extending, and proto-oceanic crust developing, establishing the rift margin evolution model for the conjugate rift margin of the SW sub-basin of the SCS. This study also identifies a "crocodile-jaw" structure in the crust of the conjugate margin of the Ⅴ-shaped tip at the SW sub-basin of the SCS, recognizing two phases of proto-oceanic crust with total width of 231 km. Based on the investigation of the outer high and syn-breakup sequence (S4 and S5), we propose that the two phases of proto-oceanic crust developing correspond to two episodes of the seafloor spreading at SW sub-basin of the SCS, and that the proto-oceanic crust constitutes the oceanic-continental transition zone between the continental margin and the synchronous oceanic crust. This study reveals the mechanism of the lithospheric thinning and break-up, and the influence of episodic seafloor spreading during the ridge propagation process on the tectonic structure, stratigraphic sequence and magmatic activity. The research will significant deepen our understanding of the rifting process at the SCS, causes of oceanic-continental transition zones, and dynamic mechanisms involved in the formation of passive continental margins at the SCS.
-
图 1 研究区域海底地形图及地震测线位置(图中红色线条)
Fig. 1. Map of the study area located in SW Sub-basin of the SCS (the locations of seismic lines N9 and N10 displayed in red lines in map)
图 2 N9测线地震剖面
a.时间剖面; b.解释剖面和Wheeler图; c.时深转换剖面
Fig. 2. Reflection seismic line N9 (for location see Fig.1)
图 3 N10测线地震剖面
a. 时间剖面; b. 解释剖面和Wheeler图; c. 时深转换剖面
Fig. 3. Reflection seismic line N10
图 7 南海西南次海盆“Ⅴ”型尖端各构造域分布平面图
a.地形图；b.磁异常图（磁条带解释参考Briais et al.，1993）；c.布格重力异常图；d.测线与各构造域图.参考测线中1来自Franke et al.（2014）；2、10、16、12来自SIO；3、7来自Luo et al.（2021）；4来自Zhang et al.（2020）；5、14来自Ding et al.（2016）；6、8、14来自Song et al.（2019）；9、15、11、17来自Chang et al.（2022）
Fig. 7. The distribution of tectonic domains of Ⅴ-shaped tip of SW sub-basin of the SCS
图 8 西南次海盆Ⅴ型尖端原洋域发育演化示意图(演化顺序为a至c)
Fig. 8. The proto-oceanic domain evolution of Ⅴ-shaped tip of SW sub-basin of the SCS (the evolution sequence is from a to c)
图 9 南海与西南次海盆构造演化时间格架
Fig. 9. Time frame for the evolution of SCS and SW sub-basin of SCS
-
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: Solid Earth, 98(B4): 6299-6328. https://doi.org/10.1029/92jb02280 Chang, S. P., Pubellier, M., Delescluse, M., et al., 2022. Crustal Architecture and Evolution of the Southwestern South China Sea: Implications to Continental Breakup. Marine and Petroleum Geology, 136: 105450. https://doi.org/10.1016/j.marpetgeo.2021.105450 Chao, P., Manatschal, G., Chenin, P., et al., 2021. The Tectono-Stratigraphic and Magmatic Evolution of Conjugate Rifted Margins: Insights from the NW South China Sea. Journal of Geodynamics, 148: 101877. https://doi.org/10.1016/j.jog.2021.101877 Chao, P., Manatschal, G., Zhang, C. M., et al., 2023. The Transition from Continental to Lithospheric Breakup Recorded in Proto-Oceanic Crust: Insights from the NW South China Sea. GSA Bulletin, 135(3-4): 886-902. https://doi.org/10.1130/b36371.1 Chenin, P., Schmalholz, S. M., Manatschal, G., et al., 2018. Necking of the Lithosphere: A Reappraisal of Basic Concepts with Thermo-Mechanical Numerical Modeling. Journal of Geophysical Research: Solid Earth, 123(6): 5279-5299. https://doi.org/10.1029/2017jb014155 Ding, W. W., 2021. Continental Margin Dynamics of South China Sea: From Continental Break-up to Seafloor Spreading. Earth Science, 46(3): 790-800 (in Chinese with English abstract). Ding, W. W., Franke, D., Li, J. B., et al., 2013. Seismic Stratigraphy and Tectonic Structure from a Composite Multi-Channel Seismic Profile across the Entire Dangerous Grounds, South China Sea. Tectonophysics, 582: 162-176. https://doi.org/10.1016/j.tecto.2012.09.026 Ding, W. W., Li, J. B., 2016. Conjugate Margin Pattern of the Southwest Sub-Basin, South China Sea: Insights from Deformation Structures in the Continent-Ocean Transition Zone. Geological Journal, 51(S1): 524-534. https://doi.org/10.1002/gj.2733 Ding, W. W., Li, J. B., Clift, P. D., 2016. Spreading Dynamics and Sedimentary Process of the Southwest Sub-Basin, South China Sea: Constraints from Multi-Channel Seismic Data and IODP Expedition 349. Journal of Asian Earth Sciences, 115: 97-113. https://doi.org/10.1016/j.jseaes.2015.09.013 Ding, W. W., Sun, Z., Mohn, G., et al., 2020. Lateral Evolution of the Rift-to-Drift Transition in the South China Sea: Evidence from Multi-Channel Seismic Data and IODP Expeditions 367 & 368 Drilling Results. Earth and Planetary Science Letters, 531: 115932. https://doi.org/10.1016/j.epsl.2019.115932 Franke, D., Savva, D., Pubellier, M., et al., 2014. The Final Rifting Evolution in the South China Sea. Marine and Petroleum Geology, 58: 704-720. https://doi.org/10.1016/j.marpetgeo.2013.11.020 Gao, H. F., Chen, L., 2006. An Analysis of Structural Framework and Formation Mechanism of Zhongjiannan Basin in the West of South China Sea. Oil & Gas Geology, 27(4): 512-516 (in Chinese with English abstract). doi: 10.3321/j.issn:0253-9985.2006.04.011 Gillard, M., Autin, J., Manatschal, G., et al., 2015. Tectonomagmatic Evolution of the Final Stages of Rifting along the Deep Conjugate Australian-Antarctic Magma-Poor Rifted Margins: Constraints from Seismic Observations. Tectonics, 34(4): 753-783. https://doi.org/10.1002/2015tc003850 Hall, R., 2000. Cenozoic Plate Tectonic Reconstructions of SE Asia. Geological Society, London, Special Publications, 126(1): 11-23. https://doi.org/10.1144/gsl.sp.1997.126.01.03 Hall, R., Spakman, W., 2015. Mantle Structure and Tectonic History of SE Asia. Tectonophysics, 658: 14-45. https://doi.org/10.1016/j.tecto.2015.07.003 Huang, C. J., 2005. Deep Crustal Structure of Baiyun Sag, Northern South China Sea Revealed from Deep Seismic Reflection Profile. Chinese Science Bulletin, 50(11): 1131. https://doi.org/10.1360/04wd0207 Ji, S. C., Li, L., Xu, Z. Q., 2021. Dislocation Creep and Flow Strength of the Earth's Crust. Acta Geologica Sinica, 95(1): 159-181 (in Chinese with English abstract). 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(10): 782-789. https://doi.org/10.1038/s41561-018-0198-1 Lavier, L. L., Manatschal, G., 2006. A Mechanism to Thin the Continental Lithosphere at Magma-Poor Margins. Nature, 440(7082): 324-328. https://doi.org/10.1038/nature04608 Lee, T. Y., Lawver, L. A., 1994. Cenozoic Plate Reconstruction of the South China Sea Region. Tectonophysics, 235(1-2): 149-180. https://doi.org/10.1016/0040-1951(94)90022-1 Lei, C., Ren, J. Y., Pang, X., et al., 2018. Continental Rifting and Sediment Infill in the Distal Part of the Northern South China Sea in the Western Pacific Region: Challenge on the Present-Day Models for the Passive Margins. Marine and Petroleum Geology, 93: 166-181. https://doi.org/10.1016/j.marpetgeo.2018.02.020 Lei, C., Alves, T. M., Ren, J. Y., et al., 2020. Rift Structure and Sediment Infill of Hyperextended Continental Crust: Insights from 3D Seismic and Well Data (Xisha Trough, South China Sea). Journal of Geophysical Research: Solid Earth, 125(5): e2019JB018610. https://doi.org/10.1029/2019JB018610 Li, J. B., Ding, W. W., Gao, J. Y., et al., 2011. Cenozoic Evolution Model of the Sea-Floor Spreading in South China Sea: New Constraints from High Resolution Geophysical Data. Chinese Journal of Geophysics, 54(12): 3004-3015 (in Chinese with English abstract). doi: 10.3969/j.issn.0001-5733.2011.12.003 Li, J. B., Ding, W. W., Wu, Z. Y., et al., 2012. The Propagation of Seafloor Spreading in the Southwestern Subbasin, South China Sea. Chinese Science Bulletin, 57(24): 3182-3191. https://doi.org/10.1007/s11434-012-5329-2 Luo, P., Manatschal, G., Ren, J. Y., et al., 2021. Tectono -Magmatic and Stratigraphic Evolution of Final Rifting and Breakup: Evidence from the Tip of the Southwestern Propagator in the South China Sea. Marine and Petroleum Geology, 129: 105079. https://doi.org/10.1016/j.marpetgeo.2021.105079 Masini, E., Manatschal, G., Mohn, G., 2013. The Alpine Tethys Rifted Margins: Reconciling Old and New Ideas to Understand the Stratigraphic Architecture of Magma-Poor Rifted Margins. Sedimentology, 60(1): 174-196. https://doi.org/10.1111/sed.12017 Morley, C. K., 2016. Major Unconformities/Termination of Extension Events and Associated Surfaces in the South China Seas: Review and Implications for Tectonic Development. Journal of Asian Earth Sciences, 120: 62-86. https://doi.org/10.1016/j.jseaes.2016.01.013 Nirrengarten, M., Mohn, G., Kusznir, N. J., et al., 2020. Extension Modes and Breakup Processes of the Southeast China-Northwest Palawan Conjugate Rifted Margins. Marine and Petroleum Geology, 113: 104123. https://doi.org/10.1016/j.marpetgeo.2019.104123 Pang, X., Chen, C. M., Peng, D. J., et al., 2007. Sequence Stratigraphy of Deep-Water Fan System of Pearl River, South China Sea. Earth Science Frontiers, 14(1): 220-229. https://doi.org/10.1016/s1872-5791(07)60010-4 Pang, X., Ren, J. Y., Zheng, J. Y., et al., 2018. Petroleum Geology Controlled by Extensive Detachment Thinning of Continental Margin Crust: A Case Study of Baiyun Sag in the Deep-Water Area of Northern South China Sea. Petroleum Exploration and Development, 45(1): 29-42. https://doi.org/10.1016/s1876-3804(18)30003-x Penrose, C. P., 1972. Penrose Field Conference on Ophiolites. Geotimes, 17: 24-25. Peron-Pinvidic, G., Manatschal, G., Osmundsen, P. T., 2013. Structural Comparison of Archetypal Atlantic Rifted Margins: A Review of Observations and Concepts. Marine and Petroleum Geology, 43: 21-47. https://doi.org/10.1016/j.marpetgeo.2013.02.002 Pubellier, M., Meresse, F., 2013. Phanerozoic Growth of Asia: Geodynamic Processes and Evolution. Journal of Asian Earth Sciences, 72: 118-128. https://doi.org/10.1016/j.jseaes.2012.06.013 Ren, J. Y., Luo, P., Gao, Y. Y., et al., 2022. Structural, Sedimentary and Magmatic Records during Continental Breakup at Southwest Sub-Basin of South China Sea. Earth Science, 47(7): 2287-2302 (in Chinese with English abstract). Sapin, F., Ringenbach, J. C., Clerc, C., 2021. Rifted Margins Classification and Forcing Parameters. Scientific Reports, 11: 1-17. https://doi.org/10.1038/S41598-021-87648-3 Sibuet, J. C., Yeh, Y. C., Lee, C. S., 2016. Geodynamics of the South China Sea. Tectonophysics, 692: 98-119. https://doi.org/10.1016/j.tecto.2016.02.022 Song, T. R., Li, C. F., Wu, S. G., et al., 2019. Extensional Styles of the Conjugate Rifted Margins of the South China Sea. Journal of Asian Earth Sciences, 177: 117-128. https://doi.org/10.1016/j.jseaes.2019.03.008 Sutra, E., Manatschal, G., Mohn, G., et al., 2013. Quantification and Restoration of Extensional Deformation along the Western Iberia and Newfoundland Rifted Margins. Geochemistry, Geophysics, Geosystems, 14(8): 2575-2597. https://doi.org/10.1002/ggge.20135 Taylor, B., Hayes, D. E., 1983. Origin and History of the South China Sea Basin. Geophysical Monograph Series. American Geophysical Union, Washington, D. C., 23-56. https://doi.org/10.1029/gm027p0023 Tugend, J., Gillard, M., Manatschal, G., et al., 2020. Reappraisal of the Magma-Rich versus Magma-Poor Rifted Margin Archetypes. Geological Society, London, Special Publications, 476(1): 23-47. https://doi.org/10.1144/sp476.9 Tugend, J., Manatschal, G., Kusznir, N. J., et al., 2014. Formation and Deformation of Hyperextended Rift Systems: Insights from Rift Domain Mapping in the Bay of Biscay-Pyrenees. Tectonics, 33(7): 1239-1276. https://doi.org/10.1002/2014TC003529 Warner, M. R., 1987. Seismic Reflections from the Moho: The Effect of Isostasy. Geophysical Journal International, 88(2): 425-435. https://doi.org/10.1111/j.1365-246x.1987.tb06651.x Xie, X. N., Ren, J. Y., Pang, X., et al., 2019. Stratigraphic Architectures and Associated Unconformities of Pearl River Mouth Basin during Rifting and Lithospheric Breakup of the South China Sea. Marine Geophysical Research, 40(2): 129-144. https://doi.org/10.1007/s11001-019-09378-6 Xie, X. N., Zhao, S., Ren, J. Y., et al., 2022. Marginal Sea Closure Process and Genetic Mechanism of South China Sea during Post-Spreading Period. Earth Science, 47(10): 3524-3542 (in Chinese with English abstract). Zhang, J., Wu, Z. C., Shen, Z. Y., et al., 2020. Seismic Evidence for the Crustal Deformation and Kinematic Evolution of the Nansha Block, South China Sea. Journal of Asian Earth Sciences, 203: 104536. https://doi.org.10.1016/j.jseaes.2020.104536 Zhao, W., Fang, N. Q., Zhan, H. M., et al., 2013. Cenozoic Tectonic Migration in the Northern Sourth China Sea. Marine Geology Frontiers, 29(4): 1-6 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-HYDT201304003.htm Zhu, R. W., Liu, H. L., Yao, Y. J., et al., 2020. Cenozoic Tectonic Subsidence of the Continental Margins of Southwest Sub-Basin, South China Sea and Its Evolution. Marine Geology & Quaternary Geology, 40(6): 82-92 (in Chinese with English abstract). 丁巍伟, 2021. 南海大陆边缘动力学: 从陆缘破裂到海底扩张. 地球科学, 46(3): 790-800. doi: 10.3799/dqkx.2020.303 高红芳, 陈玲, 2006. 南海西部中建南盆地构造格架及形成机制分析. 石油与天然气地质, 27(4): 512-516. doi: 10.3321/j.issn:0253-9985.2006.04.011 嵇少丞, 黎乐, 许志琴, 2021. 岩石圈的流变性与大陆动力学的科学基础. 地质学报, 95(1): 159-181. 李家彪, 丁巍伟, 高金耀, 等, 2011. 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, 54(12): 3004-3015. 任建业, 罗盼, 高圆圆, 等, 2022. 南海西南次海盆地壳岩石圈伸展破裂过程的构造、沉积和岩浆作用记录. 地球科学, 47(7): 2287-2302. doi: 10.3799/dqkx.2022.135 解习农, 赵帅, 任建业, 等, 2022. 南海后扩张期大陆边缘闭合过程及成因机制. 地球科学, 47(10): 3524-3542. doi: 10.3799/dqkx.2022.265 赵卫, 方念乔, 詹华明, 等, 2013. 南海北部新生代构造迁移特征. 海洋地质前沿, 29(4): 1-6. 朱荣伟, 刘海龄, 姚永坚, 等, 2020. 南海西南次海盆两侧陆缘新生代构造沉降特征及演化过程. 海洋地质与第四纪地质, 40(6): 82-92. -
下载:
点击查看大图
图(10)
计量
- 文章访问数: 255
- HTML全文浏览量: 102
- PDF下载量: 43
- 被引次数: 0
