Analysis on the Formation of the Thin Continental Crust in the South China Sea
-
摘要: 南海中央海盆南、北两侧陆缘分布着面积较广的减薄陆壳，正确认识海盆减薄陆壳的成因是研究南海构造演化的重要一环.通过分析基于地壳伸展因子公式计算的南海地壳拉张伸展特征和解释中生代以来的陆壳隆升特征等，证实晚中生代以来至渐新世末，该区不仅发生了地壳拉张伸展作用，还发生了较长期的地壳隆升挤压作用，致使酸性侵入岩出露地表，减薄陆壳区的上地壳厚薄分布不均.始新世南海南部发育海陆过渡相和海相沉积、北部仅为陆相沉积，暗示始新世南海古地理格局是南、北陆缘具有不同沉积环境的盆地群，二者之间应该被隆起所隔.这些地质现象说明该区地壳隆升剥蚀与地壳拉张伸展活动时间有较长的重叠.南海中央海盆两侧减薄陆壳的成因不仅仅是地壳拉张伸展所致，而是拉张伸展与隆升剥蚀共同作用的结果，因此可以认为在曾经发生了地壳隆升挤压而遭受长期剥蚀的区域，如果用全地壳伸展因子的公式来估算地壳拉张伸展程度，将得出错误的结论.Abstract: The thin continental crust in the South China Sea belonging to the margin sea is distributed at the sides of the Center basin. The correct understanding of the formation causes of the thin crust is a key link to the tectonic evolution of the South China Sea. Based on the calculation of the crust stretching factors and the interpretation of the crust uplift and erosion since Mesozoic, the formation of the thin continental crust in the South China Sea is considered to be not only by stretch and extension but also by uplift and erosion from Late-Mesozoic to End-Oligocene resulting in the exposure of acid-intrusive rocks on ground and the heterogeneous thickness of the upper crust at thin continental crust. In the South China Sea, the strata in Eocene with both land-marine transitive facies and marine facies deposited at the south margin, but only continental facies deposited at the north margin, which suggests that the basins developed at the north and south continental margins of the South China Sea were of different depositional environments with uplift zones between them. All of the geological characteristics mentioned above indicate that there was ever an occasion of overlap occurring time between the uplift event and extension event. The formation of the thin continental crust in the South China Sea was not only by stretching and extension but also by both extension and erosion. It will reach a wrong conclusion that the extension extent of thin continental crust is still calculated by the formula of the total crustal extensive factor at an area where long-time uplift and erosion once occurred.
-
图 1 南海地形特征与测线位置
Fig. 1. Topography of the South China Sea and the location of the profiles
图 2 西南次海盆及邻区地壳结构特征
测线位置见图 1；图中数字表示该点附近的平均P波速度，单位km/s；NCOT和SCOT所指示的区域为西南次海盆南北两侧的陆-洋过渡壳
Fig. 2. Crustal structure of the southwest sub-basin and its sides
图 3 南海莫霍面埋深图与减薄陆壳分布示意
图据杨胜雄等（2015）修改；箭头延伸区域为减薄陆壳的分布，从莫霍面埋深-32 km至-16 km，箭头所指的线条大致为减薄陆壳与陆-洋过渡带的分界，在莫霍面埋深-16 km深度左右；图中蓝色线条表示图 4的CFT剖面所在位置
Fig. 3. Depthisolines of Moho surface and the distribution of the thin continental crust in the South China Sea
图 5 南海陆缘地壳结构与上地壳和全地壳伸展因子
a.南海北部陆缘西侧(NHG-1-N测线); b.南海北部陆缘东侧(NHG-2-N测线); c.南海南部陆缘西侧(NHG-1-S测线); d.南海南部陆缘东侧(NHG-2-S测线); 红色线为计算的上地壳伸展因子，绿色线为计算的全地壳伸展因子
Fig. 5. The structure of the continental crust and the upper-crust and whole stretching factor in the South China Sea
图 6 OBS（OBS2006-3）解释的速度和地壳结构模型
测线位置见图 1，据卫小冬等（2010）修改；图中数字表示该点附近的平均P波速度，单位km/s；上地壳分离，对应距离坐标可知被拉断最短距离大致为110 km
Fig. 6. Velocity and crustal constructive model calculated by the data of OBS2006-3
图 7 OBS 1993（a）和OBS 2003（b）测线解释的速度和地壳结构模型
测线位置见图 1；图中数字表示该点附近的平均P波速度，单位km/s；图a据阎贫和刘海龄（2002）修改；图b据周龙泉等（2005）修改
Fig. 7. Velocity and crustal constructive model calculated by the data of OBS1993 (a) and OBS2003 (b)
图 8 南海中生代酸性侵入岩（晚中生代和新生代盆地沉积基底的组成部分）分布
Fig. 8. Distribution of Mesozoic acid-intrusive rocks as the sedimentary basement of Late-Mesozoic and Cenozoic basins in the South China Sea
图 9 OBH1996-4测线解释的西沙海槽速度和地壳结构
测线位置见图 1，据Qiu et al.（2001）修改；图中数字表示该点附近的平均P波速度，单位km/s
Fig. 9. Velocity and crustal constructive model of the Xisha trough calculated by the data of OBH1996-4
图 10 南海中部始新世至渐新世古地理格局变化与上地壳剥蚀示意
a.早始新世古地理格局；b.始新世末至渐新世初古地理格局
Fig. 10. Schematic map of the evolution of the ancient geography framework and upper-crust erosion from Eocene to Oligocene in the center of the South China Sea
-
[1] 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). http://www.researchgate.net/publication/286203459_Crustal_structure_of_the_Northwest_Sub-Basin_of_the_South_China_Sea_and_its_tectonic_implication [2] Cameselle, A. L., Ranero, C. R., Franke, D., et al., 2015. The Continent-Ocean Transition on the Northwestern South China Sea. Basin Research, 29: 73-95. https://doi.org/10.1111/bre.12137 [3] Chen, G. N., 1989. Remelting-in-Situ: A New Model for the Genesis of the Mesozoic Granitoids in the Southeast China Diwa Region. Geotectonica et Metallogenia, 13(2): 136-149 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/ http://search.cnki.net/down/default.aspx?filename=DGYK198902006&dbcode=CJFD&year=1989&dflag=pdfdown [4] Chen, G. N., Grapes, R., 2007. Granite Genesis: In Situ Melting and Crustal Evolution. Springer, Berlin. [5] Davis, M., Kusznir, N., 2004. Depth-Dependent Lithospheric Stretching at Rifted Continental Margins. Columbia University Press, New York. [6] Ding, W. W., Li, J. B., 2011. 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 Journal of Geophysics, 54(12): 3038-3056 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-DQWX201112008.htm [7] Franke, D., Barckhausen, U., Baristeas, N., et al., 2011. The Continent-Ocean Transition at the Southeastern Margin of the South China Sea. Marine and Petroleum Geology, 28(6): 1187-1204. https://doi.org/10.1016/j.marpetgeo.2011.01.004 [8] Gong, Z. S., Li, S. T., Xie, T. J., et al., 1997. Basins Analysis and Oil-Gas Gathering at the Continental Margin of the South China Sea. Science Press, Beijing (in Chinese). [9] He, C., Long, G. Y., Wu, S. M., 2012. Estimation of the Stretching Factors of the Qiongdongnan Basin and Domino-Style Fault Model. Geotectonica et Metallogenia, 36(2): 204-208 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/ http://search.cnki.net/down/default.aspx?filename=DGYK201202009&dbcode=CJFD&year=2012&dflag=pdfdown [10] Hsu, S. K., Yeh, Y. C., Doo, W. B., et al., 2004. New Bathymetry and Magnetic Lineations Identifications in the Northernmost South China Sea and Their Tectonic Implications. Marine Geophysical Researches, 25(1-2): 29-44. https://doi.org/10.1007/s11001-005-0731-7 [11] Kudrass, H. R., Wiedicke, M., Cepek, P., et al., 1986. Mesozoic and Cainozoic Rocks Dredged from the South China Sea (Reed Bank Area) and Sulu Sea and Their Significance for Plate-Tectonic Reconstructions. Marine and Petroleum Geology, 3(1): 19-30. https://doi.org/10.1016/0264-8172(86)90053-X [12] Kusznir, N. J., Karner, G. D., 2007. Continental Lithospheric Thinning and Breakup in Response to Upwelling Divergent Mantle Flow: Application to the Woodlark, Newfoundland and Iberia Margins. Geological Society, London, Special Publications, 282(1): 389-419. https://doi.org/10.1144/sp282.16 [13] Li, S. Z., Suo, Y. H., Dai, L. M., et al., 2010. Development of the Bohai Bay Basin and Destruction of the North China Craton. Earth Science Frontiers, 17(4): 64-89 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-DXQY201004009.htm [14] Lister, G. S., Etheridge, M. A., Symonds, P. A., 1986. Detachment Faulting and the Evolution of Passive Continental Margins. Geology, 14(3): 246-250. https://doi.org/10.1130/0091-7613(1986)14246:dfateo>2.0.co;2 doi: 10.1130/0091-7613(1986)14246:dfateo>2.0.co;2 [15] Liu, H. L., Yang, S. K., Liu, Z. S., et al., 1991. Basic Features and Evolutional Process of Dispersed Block of Meso-Cenozoic South China Continental Margin. Tropic Oceanology, 10(3): 37-43 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-RDHY199103005.htm [16] Mckenzie, D., 1978. Some Remarks on the Development of Sedimentary Basins. Earth and Planetary Science Letters, 40(1): 25-32. https://doi.org/10.1016/0012-821X(78)90071-7 [17] Nakamura, Y., Donoho, P. L., Roper, P. H., et al., 1987. Large-Offset Seismic Surveying Using Ocean-Bottom Seismographs and Air Guns: Instrumentation and Field Technique. Geophysics, 52(12): 1601-1611. https://doi.org/10.1190/1.1442277 [18] Nissen, S. S., Hayes, D. E., Buhl, P., et al., 1995. Deep Penetration Seismic Soundingsacross the Northern Margin of the South China Sea. Journal of Geophysical Research: Solid Earth, 100(B11): 22407-22433. https://doi.org/10.1029/95JB01866 [19] Northrup, C. J., Royden, L. H., Burchfiel, B. C., 1995. Motion of the Pacific Plate Relative to Eurasia and Its Potential Relation to Cenozoic Extension along the Eastern Margin of Eurasia. Geology, 23(8): 719-722. https://doi.org/10.1130/0091-7613(1995)0230719:motppr>2.3.co;2 doi: 10.1130/0091-7613(1995)0230719:motppr>2.3.co;2 [20] Qiu, X. L., Ye, S. Y., Wu, S. M., et al., 2001. Crustal Structure across the Xisha Trough, Northwestern South China Sea. Tectonophysics, 341(1-4): 179-193. https://doi.org/10.1016/S0040-1951(01)00222-0 [21] Qiu, Y., Chen, G. N., Liu, F. L., et al., 2008. Discover of Granite and Its Tectonic Significance in Southwestern Basin of the South China Sea. Geological Bulletin of China, 27(12): 2104-2107 (in Chinese with English abstract). http://www.researchgate.net/publication/285840129_Discovery_of_granite_and_its_tectonic_significance_in_southwestern_basin_of_the_South_China_Sea [22] Qiu, Y., Wang, L. F., Huang, W. K., et al., 2016. Sedimentary Basins in Mesozoic and Cenozoic in the China Seas. Geological Publishing House, Beijing (in Chinese). [23] Ren, J. F., Sun, M., Zhu, B. D., et al., 2018. Paleo-Sedimentary Environment and Tectonic Significance of Gravel Layers at IODP Site U1499 in Northern South China Sea. Earth Science, 43(S2): 179-191 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTotal-DQKX2018S2014.htm [24] Reston, T., 2007. Extension Discrepancy at North Atlantic Nonvolcanic Rifted Margins: Depth-Dependent Stretching or Unrecognized Faulting?. Geology, 35(4): 367-370. https://doi.org/10.1130/g23213a.1 [25] Ru, K., Pigott, J. D., 1986. Episodic Rifting and Subsidence in the South China Sea. AAPG Bulletin, 70(9): 1136-1155. https://doi.org/10.1306/94886a8d-1704-11d7-8645000102c1865d [26] Ruan, A. G., Niu, X. W., Qiu, X. L., et al., 2011. A Wide Angle Ocean Bottom Seismometer Profile across Liyue Bank, the Southern Margin of South China Sea. Chinese Journal of Geophysics, 54(12): 3139-3149(in Chinese with English abstract). http://www.researchgate.net/publication/243971470_A_Wide_Angle_Ocean_Bottom_Seismometer_Experiment_Across_Liyue_Bank_the_Southern_Margin_of_the_South_China_Sea [27] Wang, Q., Zhao, M.H., Zhang, H. Y., et al., 2020. Crustal Velocity Structure of the Northwest Sub-Basin of the South China Sea Based on Seismic Data Reprocessing. Science in China (Series D), 50(11): 1553-1568 (in Chinese). http://www.researchgate.net/publication/344276183_Crustal_velocity_structure_of_the_Northwest_Sub-basin_of_the_South_China_Sea_based_on_seismic_data_reprocessing [28] Wei, X. D., Zhao, M. H., Ruan, A. G., et al., 2010. Identification and Application of Shear Waves along the Profile OBS2006-3 in the Mid-Northern South China Sea. Journal of Tropical Oceanography, 29(5): 72-80 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-RDHY201005012.htm [29] Wernicke, B., 1981. Low-Angle Normal Faults in the Basin and Range Province: Nappe Tectonics in an Extending Orogen. Nature, 291(5817): 645-648. https://doi.org/10.1038/291645a0 [30] Yan, P., Liu, H. L., 2002. Analysis on Deep Crust Sounding Results in Northern Margin of South China Sea. Journal of Tropical Oceanography, 21(2): 1-12 (in Chinese with English abstract). http://ci.nii.ac.jp/naid/10026539877 [31] Yan, P., Zhou, D., Liu, Z. S., 2001. A Crustal Structure Profile across the Northern Continental Margin of the South China Sea. Tectonophysics, 338(1): 1-21. https://doi.org/10.1016/S0040-1951(01)00062-2 [32] Yang, S. X., Qiu, Y., Zhu, B. D., et al., 2015. Atlas of Geology and Geophysics of the South China Sea (2 000 000). China Navigation Publications Press, Tianjing (in Chinese). [33] Yao, B. C., Wan, L., Zeng, W. J., et al., 2006. 3D Structure of Lithosphere of the South China Sea, China. Geological Publishing House, Beijing (in Chinese). [34] Yao, B.C., Zeng, W. J., Taylor, B., et al., 1994. The Geological Memoir of the South China Sea Surveyed Jointly by China and USA. China University of Geosciences Press, Wuhan (in Chinese). [35] Yu, P., Chen, H. G., Wang, J. L., et al., 2000. Geological-Physical Model and Interpretation of the Typical Profiles across the Passive Continental Margin of Northern South China Sea. Journal of Changchun University of Science and Technology, 30(1): 76-79 (in Chinese with English abstract). http://www.researchgate.net/publication/285639712_Geological-physical_model_and_interpretation_of_the_typical_profiles_across_the_passive_continental_margin_of_northern_south_china_sea [36] Yu, Z. T., Li, J. B., Ding, W. W., et al., 2017. Crustal Structure of the Southwest Subbasin, South China Sea, from Wide-Angle Seismic Tomography and Seismic Reflection Imaging. Marine Geophysical Research, 38(1-2): 85-104. https://doi.org/10.1007/s11001-016-9284-1 [37] 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): 27-36 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-DXQY201503003.htm [38] Zhou, L. Q., Liu, F. T., Liu, J. S., et al., 2005. Determination of the Crustal Velocity Model of Dongsha Islands Using the Inversion of τ-p Wave Field. Progress in Geophysics, 20(2): 503-506 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-DQWJ200502046.htm [39] 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, 37(4): 779-790. http://www.earth-science.net/article/id/2284 [40] 陈国能, 1989. 原地重熔: 中国东南地洼区中生代花岗岩的重要形成途径. 大地构造与成矿学, 13(2): 136-149. https://www.cnki.com.cn/Article/CJFDTOTAL-DGYK198902006.htm [41] 丁巍伟, 李家彪, 2011. 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, 54(12): 3038-3056. doi: 10.3969/j.issn.0001-5733.2011.12.006 [42] 龚再升, 李思田, 谢泰俊, 等, 1997. 南海北部大陆边缘盆地分析与油气聚集. 北京: 科学出版社. [43] 贺超, 龙根元, 吴世敏, 2012. 琼东南盆地地壳伸展因子计算及其伸展模式探讨. 大地构造与成矿学, 36(2): 204-208. doi: 10.3969/j.issn.1001-1552.2012.02.007 [44] 李三忠, 索艳慧, 戴黎明, 等, 2010. 渤海湾盆地形成与华北克拉通破坏. 地学前缘, 17(4): 64-89. https://www.cnki.com.cn/Article/CJFDTOTAL-DXQY201004009.htm [45] 刘海龄, 杨树康, 刘昭蜀, 等, 1991. 中、新生代华南陆缘离散地块的基本特征及演化过程. 热带海洋, 10(3): 37-43. https://www.cnki.com.cn/Article/CJFDTOTAL-RDHY199103005.htm [46] 邱燕, 陈国能, 刘方兰, 等, 2008. 南海西南海盆花岗岩的发现及其构造意义. 地质通报, 27(12): 2104-2107. doi: 10.3969/j.issn.1671-2552.2008.12.017 [47] 邱燕, 王立飞, 黄文凯, 等, 2016. 中国海域中新生代沉积盆地. 北京: 地质出版社. [48] 任金锋, 孙鸣, 朱本铎, 等, 2018. 南海北部IODP U1499站位砾石层的古沉积环境及构造意义. 地球科学, 43(S2): 179-191. doi: 10.3799/dqkx.2018.209 [49] 阮爱国, 牛雄伟, 丘学林, 等, 2011. 穿越南沙礼乐滩的海底地震仪广角地震试验. 地球物理学报, 54(12): 3139-3149. doi: 10.3969/j.issn.0001-5733.2011.12.014 [50] 王强, 赵明辉, 张浩宇, 等, 2020. 基于重处理数据的南海西北次海盆地壳速度结构. 中国科学(D辑), 50(11): 1553-1568. https://www.cnki.com.cn/Article/CJFDTOTAL-JDXK202011003.htm [51] 卫小冬, 赵明辉, 阮爱国, 等, 2010. 南海中北部OBS2006-3地震剖面中横波的识别与应用. 热带海洋学报, 29(5): 72-80. doi: 10.3969/j.issn.1009-5470.2010.05.011 [52] 阎贫, 刘海龄, 2002. 南海北部陆缘地壳结构探测结果分析. 热带海洋学报, 21(2): 1-12. doi: 10.3969/j.issn.1009-5470.2002.02.001 [53] 杨胜雄, 邱燕, 朱本铎, 等, 2015. 南海地质地球物理图系(1: 2 000 000). 天津: 中国航海图书出版社. [54] 姚伯初, 万玲, 曾维军, 等, 2006. 中国南海海域岩石圈三维结构及演化. 北京: 地质出版社. [55] 姚伯初, 曾维军, Taylor, B., 等, 1994. 中美合作调研南海地质专报. 武汉: 中国地质大学出版社. [56] 于鹏, 陈华根, 王家林, 等, 2000. 南海北部被动陆缘典型剖面的地质-物理模型及其综合解释. 长春科技大学学报, 30(1): 76-79. doi: 10.3969/j.issn.1671-5888.2000.01.019 [57] 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): 27-36. https://www.cnki.com.cn/Article/CJFDTOTAL-DXQY201503003.htm [58] 周龙泉, 刘福田, 刘劲松, 等, 2005. 利用τ-p波场反演法确定东沙群岛的地壳速度模型. 地球物理学进展, 20(2): 503-506. doi: 10.3969/j.issn.1004-2903.2005.02.046 -
下载:
点击查看大图
图(11)
计量
- 文章访问数: 713
- HTML全文浏览量: 205
- PDF下载量: 107
- 被引次数: 0
