Crustal structure features and origins of high-velocity lower crust in the northeastern South China Sea

doi:10.3969/j.issn.1001-909X.2019.02.005

Abstract

Abstract: Abundant information about tectonic evolution in the northeastern South China Sea margin is essentially important for understanding the evolution of the South China Sea. The deep reflection seismic profiles and wide-angle reflection seismic profiles across the northeastern South China Sea were collected, and the crustal thickness and high-velocity lower crustal thickness were extracted respectively. Combining with geological and geophysical information such as bathymetry, gravity and magnetic anomalies, and lithospheric rheology, the crustal thinning of the northeastern South China Sea, nature of the Luzon-Ryukyu Transform Plate Boundary and distribution of the high-velocity lower crust and its origins were discussed. The northeastern crust is unevenly thin in lateral and vertical, dominated with lower crust thinning, like in the Taixinan Basin. There are similar extremely thinned crusts in the Baiyun Sag, Xisha Trough and Zhongjiannan Basin. They are always conjugated with or adjacent to rigid blocks. We agree that lower crust flow and mantle upwell caused by the existence of rigid blocks during initiated breakup are responsible for locally extreme thinning of the crust. Both sides of the Luzon-Ryukyu Transform Plate Boundary are different in the bathymetry, Cenozoic reflections, gravity and magnetic anomalies. The LRTPB intersected high magnetic anomaly zone caused by Mesozoic with a large-angle, indicating the Luzon-Ryukyu Transform Plate Boundary may be a boundary fault converted from the Mesozoic Paleo-Tethys tectonic domain to the Pacific tectonic domain. The distribution range of the extensive HVLC in the northeastern margin consistent with post-rift igneous. Combining with distribution interval of ratios V_p/V_s of the high-velocity lower crust, It is suggested that the high-velocity lower crust primarily consists of mafic rock caused by multiple-epoch underplating.

Key words: the northeastern South China Sea, crustal thickness, extremely thinning, Luzon-Ryukyu Transform Plate Boundary, high-velocity lower crust

CLC Number:

P736.1

LI Hai-long, WU Zhao-cai, XU ming-ju. Crustal structure features and origins of high-velocity lower crust in the northeastern South China Sea[J]. Journal of Marine Sciences, 2019, 37(2): 44-56.

References

[1] LI Jia-biao. Dynamics of the continental margins of South China Sea: scientific experiments and research progresses[J]. Chinese Journal of Geophysics, 2011, 54(12): 2 993-3 003.
李家彪. 南海大陆边缘动力学:科学实验与研究进展[J]. 地球物理学报, 2011, 54(12): 2 993-3 003.
[2] TAYLOR B, HAYES D E. Origin and history of the South China Sea Basin[M]//HAYES D E. The tectonic and geologic evolution of Southeast Asian seas and islands. American Geophysical Union, 1983: 27, 23-56.
[3] HSU S K, YEH Y C, DOO W B, et al. New bathymetry and magnetic lineations identifications in the northernmost South China Sea and their tectonic implications[J]. Marine Geophysical Research, 2004, 25(1): 29-44.
[4] YEH Y C, SIBUET J C, HSU S K, et al. Tectonic evolution of the Northeastern South China Sea from seismic interpretation[J]. Journal of Geophysical Research Solid Earth, 2010, 115(B6): 258-273.
[5] YEH Y C, HSU S K, DOO W B, et al. Crustal features of the northeastern South China Sea: insights from seismic and magnetic interpretations[J]. Marine Geophysical Research, 2012, 33(4): 307-326.
[6] LESTER R, MCINTOSH K, VAN AVENDONK H J A, et al. Crustal accretion in the Manila trench accretionary wedge at the transition from subduction to mountain-building in Taiwan[J]. Earth & Planetary Science Letters, 2013, 375(8): 430-440.
[7] MCINTOSH K D, VAN AVENDONK H J, LAVIER L L, et al. Inversion of a hyper-extended rifted margin in the southern Central Range of Taiwan[J]. Geology, 2013, 41(8): 871-874.
[8] SIBUET J C, YEH Y C, LEE C S. Geodynamics of the South China Sea[J]. Tectonophysics, 2016, 692(B): 98-119.
[9] LESTER R, VAN AVENDONK H J A, MCINTOSH K, et al. Rifting and magmatism in the northeastern South China Sea from wide-angle tomography and seismic reflection imaging[J]. Journal of Geophysical Research Solid Earth, 2014, 119(3): 2 305-2 323.
[10] MCINTOSH K, LAVIER L, VAN AVENDONK H, et al. Crustal structure and inferred rifting processes in the northeast South China Sea[J]. Marine & Petroleum Geology, 2014, 58(B): 612-626.
[11] EAKIN D H, VAN AVENDONK H J A, LAVIER L, et al. Crustal-scale seismic profiles across the Manila subduction zone: The transition from intraoceanic subduction to incipient collision[J]. Journal of Geophysical Research Solid Earth, 2014, 119(1): 1-17.
[12] HUANG Chun-ju, ZHOU Di, CHEN Chang-min, et al. The deep crustal structure of the Baiyun sag revealed by the deep reflection seismic profiles[J]. Chinese Science Bulletin, 2005, 50(10): 1 024-1 031.
黄春菊,周蒂,陈长民,等. 深反射地震剖面所揭示的白云凹陷的深部地壳结构[J]. 科学通报, 2005, 50(10): 1 024-1 031.
[13] NISSEN S S, HAYES D E, BUHL P, et al. Deep penetration seismic soundings across the northern margin of the South China Sea[J]. Journal of Geophysical Research Solid Earth, 1995, 100(B11): 22 407-22 434.
[14] WAN Kui-yuan, XIA Shao-hong, CAO Jing-he, et al. Deep seismic structure of the northeastern South China Sea: Origin of a high-velocity layer in the lower crust[J]. Journal of Geophysical Research Solid Earth, 2017, 122(4): 2 831-2 858.
[15] WANG T K, CHEN MING-KAI, LEE C S, et al. Seismic imaging of the transitional crust across the northeastern margin of the South China Sea[J]. Tectonophysics, 2006, 412(3-4): 237-254.
[16] YAN Pin, ZHOU Di, LIU Zhao-shu. A crustal structure profile across the northern continental margin of the South China Sea[J]. Tectonophysics, 2001, 338(1): 1-21.
[17] CAO Jing-he, SUN Jin-long, XU Hui-long, et al. Seismological features of the littoral fault zone in the Pearl River Estuary[J]. Chinese Journal of Geophysics, 2014, 57(2): 498-508.
曹敬贺,孙金龙,徐辉龙,等. 珠江口海域滨海断裂带的地震学特征[J]. 地球物理学报, 2014, 57(2): 498-508.
[18] WEI Xiao-Dong, RUAN Ai-guo, ZHAO Ming-hui, et al. A wide-angle OBS profile across Dongsha Uplift and Chaoshan Depression in the mid-northern South China Sea[J]. Chinese Journal of Geophysics, 2011, 54(12): 3 325-3 335.
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[J]. 地球物理学报, 2011, 54(12): 3 325-3 335.
[19] ZHOU Long-quan, LIU Fu-tian, LIU Jin-song, et al. Determination of the crustal velocity model of Dongsha Islands using the inversion τ-ρ wave field[J]. Progress in Geophysics, 2005, 20(2): 503-506.
周龙泉,刘福田,刘劲松,等. 利用τ-ρ波场反演法确定东沙群岛的地壳速度模型[J]. 地球物理学进展, 2005, 20(2): 503-506.
[20] WU Zhao-cai, GAO Jin-yao, DING Wei-wei, et al. Moho depth of the South China Sea basin from three-dimensional gravity inversion with constraint points[J]. Chinese Journal of Geophysics, 2017, 60(7): 2 599-2 613.
吴招才,高金耀,丁巍伟,等. 南海海盆三维重力约束反演莫霍面深度及其特征[J]. 地球物理学报, 2017, 60(7): 2 599-2 613.
[21] LI Song-lin, MOONEY W D, FAN Ji-chang. Crustal structure of mainland China from deep seismic sounding data[J]. Tectonophysics, 2006, 420(1): 239-252.
[22] LÜ Bing-quan, XU Guo-qiang, WANG Hong-gang, et al. Sea floor spreading recorded by drowning events of Cenozoic carbonate platforms in the South China Sea[J]. Chinese Journal of Geology, 2002, 37(4): 405-414.
吕炳全,徐国强,王红罡,等. 南海新生代碳酸盐台地淹没事件记录的海底扩张[J]. 地质科学, 2002, 37(4): 405-414.
[23] ZOU He-ping, LI Ping-lu, RAO Chun-tao. Geochemistry of Cenozoic volcanic rocks in Zhujiangkou basin and its geodynamic significance[J]. Geochimica, 1995, 3(z1): 33-45.
邹和平,李平鲁,饶春涛. 珠江口盆地新生代火山岩地球化学特征及其动力学意义[J]. 地球化学, 1995, 3(z1): 33-45.
[24] LI Ping-lu, LIANG Hui-xian. The relationship among Cenozoic magmatism, basin evolution and hydrocarbon accumulation in the Pearl River Mouth Basin[J]. Guangdong Geology, 1994, 9(2): 23-24.
李平鲁,梁慧娴. 珠江口盆地新生代岩浆活动与盆地演化,油气聚集的关系[J]. 广东地质, 1994, 9(2): 23-24.
[25] LIU Hai-ling, YAN Pin, LIU Ying-chun, et al. Existence of Qiongnan suture zone in northern margin of South China Sea[J]. Chinese Science Bulletin, 2006, 51(s3): 92-101.
刘海龄,阎贫,刘迎春,等. 南海北缘琼南缝合带的存在[J]. 科学通报, 2006, 51(s3): 92-101.
[26] ZHOU Di, WANG Wan-yin, PANG Xiong, et al. Mesozoic subduction-accretion zone in northeastern South China Sea inferred from geophysical interpretations[J]. Science in China: Series D Earth Sciences, 2006, 36(3): 209-218.
周蒂,王万银,庞雄,等. 地球物理资料所揭示的南海东北部中生代俯冲增生带[J]. 中国科学:地球科学, 2006, 36(3): 209-218.
[27] CHEN Han-zong, WU Xiang-jie, ZHOU Di, et al. Meso-Cenozoic faults in Zhujiang River mouth basin and their geodynamic background[J]. Journal of Tropical Oceanography, 2005, 24(2): 52-61.
陈汉宗,吴湘杰,周蒂,等. 珠江口盆地中新生代主要断裂特征和动力背景分析[J]. 热带海洋学报, 2005, 24(2): 52-61.
[28] CLIFT P, LIN J, BARCKHAUSEN U. Evidence of low flexural rigidity and low viscosity lower continental crust during continental break-up in the South China Sea[J]. Marine & Petroleum Geology, 2002, 19(8): 951-970.
[29] MCKENZIE D, JACKSON J A. Conditions for flow in the continental crust[J]. Tectonics, 2002, 21(6): 1-5.
[30] QIU Xue-lin, YE San-yu, WU Shi-min, et al. Crustal structure across the Xisha Trough, northwestern South China Sea[J]. Tectonophysics, 2001, 341(1-4): 179-193.
[31] SAVVA D, MERESSE F, PUBELLIER M, et al. Seismic evidence of hyper-stretched crust and mantle exhumation offshore Vietnam[J]. Tectonophysics, 2013, 608(6): 72-83.
[32] SUN Zhen, PANG Xiong, ZHONG Zhi-hong, et al. Dynamics of Tertiary tectonic evolution of the Baiyun Sag in the Pearl River Mouth Basin[J]. Geoscience Frontiers, 2005, 12(4): 489-498.
孙珍,庞雄,钟志洪,等. 珠江口盆地白云凹陷新生代构造演化动力学[J]. 地学前缘, 2005, 12(4): 489-498.
[33] ZHANG Yun-fan, SUN Zhen, ZHOU Di, et al. Crustal thinning characteristics and its kinetic significance of the continental margin of the northern South China Sea[J]. Science in China: Series D Earth Sciences, 2007, 37(12): 1 609-1 616.
张云帆,孙珍,周蒂,等. 南海北部陆缘新生代地壳减薄特征及其动力学意义[J]. 中国科学:地球科学, 2007, 37(12): 1 609-1 616.
[34] YAO Bo-chu, ZENG Wei-jun. South China Sea Xisha trough, a paleo suture line[J]. Marine Geology & Quaternary Geology, 1994,14(1): 1-10.
姚伯初,曾维军. 南海西沙海槽,一条古缝合线[J]. 海洋地质与第四纪地质, 1994, 14(1): 1-10.
[35] LEI Chao, REN Jian-ye. Hyper-extended rift systems in the Xisha Trough, northwestern South China Sea: Implications for extreme crustal thinning ahead of a propagating ocean[J]. Marine & Petroleum Geology, 2016, 77: 846-864.
[36] LI L, CLIFT P D, STEPHENSON R, et al. Non-uniform hyper-extension in advance of seafloor spreading on the Vietnam continental margin and the SW South China Sea[J]. Basin Research, 2014, 26(1): 106-134.
[37] HUISMANS R, BEAUMONT C. Depth-dependent extension, two-stage breakup and cratonic underplating at rifted margins[J]. Nature, 2011, 473(7345): 74-78.
[38] LI Chun-feng, LIN Jian, KULHANEK D K, et al. 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[J]. Integrated Ocean Drilling Program Preliminary Reports, 2014(349): 1-109.
[39] WU Shi-guo, FAN Jian-ke, DONG Dong-dong. Discussion on the tectonic division of the Philippine Sea Plate[J]. Chinese Journal of Geology, 2013, 48(3): 677-692.
吴时国,范建柯,董冬冬. 论菲律宾海板块大地构造分区[J]. 地质科学, 2013, 48(3): 677-692.
[40] SUN Zhen, ZHONG Zhi-hong, ZHOU Di, et al. Study on the developmental mechanism of the South China Sea: Similar simulation evidence[J]. Science in China: Series D Earth Sciences, 2006, 36(9): 797-810.
孙珍,钟志洪,周蒂,等. 南海的发育机制研究:相似模拟证据[J]. 中国科学:地球科学, 2006, 36(9): 797-810.
[41] LI Chun-feng, ZHOU Zu-yi, LI Jia-biao, et al. Structures of the northeasternmost South China Sea continental margin and ocean basin: geophysical constraints and tectonic implications[J]. Marine Geophysical Research, 2007, 28(1): 59-79.
[42] LI Chun-feng, ZHOU Zu-yi, HAO Hu-jun, et al. Late Mesozoic tectonic structure and evolution along the present-day northeastern South China Sea continental margin[J]. Journal of Asian Earth Sciences, 2008, 31(4-6): 546-561.
[43] WU Zhao-cai, GAO Jin-yao, LI Jia-biao, et al. The characteristics of magnetic anomalies: Implications for Pre-Cenozoic tectonics of the northern South China Sea[J]. Chinese Journal of Geophysics, 2011, 54(12): 3 292-3 302.
吴招才,高金耀,李家彪,等. 南海北部磁异常特征及对前新生代构造的指示[J]. 地球物理学报, 2011, 54(12): 3 292-3 302.
[44] WHITE R S, MCKENZIE D. Magmatism at rift zones: The generation of volcanic continental margins and flood basalts[J]. Journal of Geophysical Research, 1989, 94(B6): 7 685-7 729.
[45] BOILLOT G, RECQ M, WINTERER E L, et al. Tectonic denudation of the upper mantle along passive margins: a model based on drilling results (ODP leg 103, western Galicia margin, Spain)[J]. Tectonophysics, 1987, 132(4): 335-342.
[46] GAO Jin-wei, WU Shi-guo, MCINTOSH K, et al. The continent-ocean transition at the mid-northern margin of the South China Sea[J]. Tectonophysics, 2015, 654: 1-19.
[47] YAN Pin, DENG Hui, LIU Hai-ling, et al. The temporal and spatial distribution of volcanism in the South China Sea region[J]. Journal of Asian Earth Sciences, 2006, 27(5): 647-659.
[48] WANG Pin-xian, PRELL W L, BLUM P, et al. Proceedings of Ocean Drilling Program, Initial Report, 184.College Station[R].TX: Ocean Drilling Program, 2000.
[49] MJELDE R, KASAHARA J, SHIMAMURA H, et al. Lower crustal seismic velocity-anomalies; magmatic underplating or serpentinized peridotite? Evidence from the Vøring Margin, NE Atlantic[J]. Marine Geophysical Researches, 2002, 23(2): 169-183.
[50] MÉVEL C. Serpentinization of abyssal peridotites at mid-ocean ridges[J]. Comptes Rendus-Géoscience, 2003, 335(10): 825-852.
[51] RUDNICK R L, FOUNTAIN D M. Nature and composition of the continental crust: A lower crustal perspective[J]. Reviews of Geophysics, 1995, 33(3): 267-309.
[52] MINSHULL T A. Geophysical characterisation of the ocean-continent transition at magma-poor rifted margins[J]. Comptes Rendus Geoscience, 2009, 341(5): 382-393.
[53] ZHAO Ming-hui, QIU Xue-lin, XIA Shao-hong, 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[J]. Tectonophysics, 2010, 480(1-4): 183-197.
[54] WEI Xiao-dong, ZHAO Ming-hui, RUAN Ai-guo, et al. Crustal structure of shear waves and its tectonic significance in the mid-northern continental margin of the South China Sea[J]. Chinese Journal of Geophysics, 2011, 54(12): 3 150-3 160.
卫小冬,赵明辉,阮爱国,等. 南海中北部陆缘横波速度结构及其构造意义[J]. 地球物理学报, 2011, 54(12): 3 150-3 160.
[55] SHAO Lei, YOU Hong-qing, HAO Hu-jun, et al. Petrology and depositional environments of Mesozoic Strata in the Northeastern South China Sea[J]. Geological Review, 2007, 53(2): 164-169.
邵磊,尤洪庆,郝沪军,等. 南海东北部中生界岩石学特征及沉积环境[J]. 地质论评, 2007, 53(2): 164-169.
[56] SUN Zhen, STOCK J, JIAN Zhi-min, et al. Expedition 367/368 Scientific Prospectus: South China Sea rifted margin[R]. International Ocean Discovery Program, 2016.
[57] GHADERI N, ZHANG Huai, SUN Tao. Relative stability and contrasting elastic properties of serpentine polymorphs from first-principles calculations[J]. Journal of Geophysical Research Solid Earth, 2015, 120(7): 4 831-4 842.
[58] TANG Xiao-yin, HUANG Shao-peng, YANG Shu-chun, et al. Correcting on logging-derived temperatures of the Pearl River Mouth Basin and characteristics of its present temperature field[J]. Chinese Journal of Geophysics, 2016, 59(8): 2 911-2 921.
唐晓音,黄少鹏,杨树春,等. 南海珠江口盆地钻井BHT温度校正及现今地温场特征[J]. 地球物理学报, 2016, 59(8): 2 911-2 921.
[59] MJELDE R, RAUM T, DIGRANES P, et al. V_p / V_s ratio along the Vøring Margin, NE Atlantic, derived from OBS data: implications on lithology and stress field[J]. Tectonophysics, 2003, 369(3): 175-197.
[60] HOLBROOK S W, MOONEY W D, CHRISTENSEN N I. The seismic velocity structure of the deep continental crust[M]//FOUNTAIN D M, ARCULUS R, KAY W R. Continental lower crust. Elsevier, 1992: 1-43.
[61] XIA Shao-hong, ZHAO Ming-hui, QIU Xue-lin, et al. Crustal structure in an onshore-offshore transitional zone near Hong Kong, northern South China Sea[J]. Journal of Asian Earth Sciences, 2010, 37(5): 460-472.
[62] NISSEN S S, HAYES D E, YAO Bo-chu, et al. Gravity, heat flow, and seismic constraints on the processes of crustal extension: Northern margin of the South China Sea[J]. Journal of Geophysical Research Solid Earth, 1995, 100(B11): 22 447-22 483.