Sediment Waves in the South of South China Sea: Soft Sediment Deformation and Its Triggering Mechanism
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摘要: 目前,沉积物波的成因还是存在很多争议.通过详细的地震资料解释,发现南海南部海域有一个规模巨大的海底滑坡,滑坡体长达160 km.从剖面上看,滑坡体结构完整,由减损带、加积带、滑阻带、破坏体、滑脱面、滑坡后壁、冠上裂缝、横向裂缝等结构要素组成.在如此低的海底坡度(仅0.3°~0.5°)上形成如此大规模的滑坡体,推测是地震活动触发的.加积带内发育沉积物波.形态特征和剪应力分析显示,沉积物波形成于减损带的推挤作用.加积带中部推力最大,导致下部为逆时针剪切,上部为顺时针剪切.因此,沉积物波属于海底滑坡引起的软沉积物变形.软变形沉积物波是海底滑坡的一种特殊标志,因此这项研究有助于发现海底滑坡,也有助于海底工程的减灾防灾工作.Abstract: At present, the cause of sediment waves is still controversial. Detailed interpretation of the seismic profiles in the south of South China Sea, supports the discovery of an enormous submarine landslide, which covers a distance of 160 km. Analyzed from the seismic profiles, the landslide body consists of depletion zone, accumulation zone, main scarp, crown scarp, rupture surface, separation surface and transverse cracks. The submarine landslide was triggered by earthquake activity, according to the very low seabed slope (only 0.3°~0.5°) and the enormous scale of the landslide body. The sediment waves are common in the accumulation zone. Based on morphological characteristics and shearing stress analysis, the sediment waves formed through the compression of the depletion zone with a maximum stress in the middle part, leading to counter-clockwise shearing in the lower part and clockwise shearing in the upper part. Therefore, the sediment waves are soft sediment deformation caused by submarine landslide. Soft deformation sediment wave is a special mark of submarine landslide, and this study promotes the discovery of submarine landslide and also contributes to the disaster reduction and prevention of submarine engineering.
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图 2 地震反射剖面AA'及其地质解释
a.偏移地震反射剖面; b.地质解释.剖面位置见图 1
Fig. 2. Seismic reflection profile AA' and its geological interpretation
图 3 地震反射剖面BB'及其地质解释
剖面位置见图 1
Fig. 3. Seismic reflection profile BB' and its geological interpretation
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Bouma, A.H., Treadwell, T.K., 1975.Deep-Sea Dune-Like Features.Marine Geology, 19(5):53-59.https://doi.org/10.1016/0025-3227(75)90078-x doi: 10.1016/0025-3227(75)90078-X Briais, A., Patriat, P., Trapponier, 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, 98(B4):6299-6328.https://doi.org/10.1029/92jb02280 doi: 10.1029/92JB02280 Bryn, P., Berg, K., Forsberg, C.F., et al., 2005.Explaining the Storegga Slide.Marine and Petroleum Geology, 22(1-2):11-19. https://doi.org/10.1016/j.marpetgeo.2004.12.003 Chen, H., Xie, X.N., Mao, K.N., 2015.Deep-Water Countourite Depositional System in Vicinicy of Yitong Shoal on Northern Margin of the South China Sea.Earth Science, 40(4):733-743 (in Chinese with English abstract).https://doi.org/10.3799/dqkx.2015.061 Chigira, M., 1992.Long-Term Gravitational Deformation of Rocks by Mass Rock Creep.Engineering Geology, 32(3):157-184. doi: 10.1016/0013-7952(92)90043-X Cullen, A.B., 2010.Transverse Segmentation of the Baram-Balabac Basin, NW Borneo:Refining the Model of Borneo's Tectonic Evolution.Petroleum Geoscience, 16(1):3-29. https://doi.org/10.1144/1354-079309-828 Damuth, J.E., 1979.Migrating Sediment Waves Created by Turbidity Currents in the Northern South China Basin.Geology, 7(11):520-523.https://doi.org/10.1130/0091-7613(1979)72.0.co;2 doi: 10.1130/0091-7613(1979)7<520:MSWCBT>2.0.CO;2 Ding, W.W., Li, J.B., Han, X.Q., et al., 2010.Geomorphology, Grain-Size Characteristics, Matter Source and Forming Mechanism of Sediment Waves on the Ocean Bottom of the Northeast South China Sea.Acta Oceanologica Sinica, 32(2):96-105 (in Chinese with English abstract). Faugeres, J.C., Stow, D.A.V., Imbert, P., et al., 1999.Seismic Features Diagnostic of Contourite Drifts.Marine Geology, 162(1):1-38.https://doi.org/10.1016/s0025-3227(99)00068-7 doi: 10.1016/S0025-3227(99)00068-7 Gao, Z.Z., He, Y.B., Luo, S.S., et al., 1996.Deep Water Traction Sedimentation-Internal Tides, Internal Waves and Contour Flow Deposition.Science Publication, Beijing, 1-46 (in Chinese with English abstract). Gong, C.L., Wang, Y.M., Peng, X.C., et al., 2012.Sediment Waves on the South China Sea Slope off Southwestern Taiwan:Implications for the Intrusion of the Northern Pacific Deep Water into the South China Sea.Marine and Petroleum Geology, 32(1):95-109.https://doi.org/10.1016/j.marpetgeo.2011.12.005 Heezen, B.C., Ewing, W.M., 1952.Turbidity Currents and Submarine Slumps, and the 1929 Grand Banks Earthquake.American Journal of Science, 250(12):849-873. https://doi.org/10.2475/ajs.250.12.849 Hutchison, C.S., 1996.The 'Rajang Accretionary Prism' and 'Lupar Line' Problem of Borneo.Geological Society of London Special Publications, 106(1):247-261.https://doi.org/10.1144/gsl.sp.1996.106.01.16 doi: 10.1144/GSL.SP.1996.106.01.16 Jiang, T., Xie, X.N., Wang, Z.F., et al., 2013.Seismic Features and Origin of Sediment Waves in the Qiongdongnan Basin, Northern South China Sea.Marine Geophysical Researches, 34(3-4):281-294. https://doi.org/10.1007/s11001-013-9198-0 Karl, H.A., Carlson, P.R., 1982.Large Sand Waves in Navarinsky Canyon Head Bearing Sea.Geo-Marine Letter, 2(3/4):157-162.https://doi.org/10.1007/bf02462757 doi: 10.1007-BF02462757/ Krebs, W.N., 2011.Upper Tertiary Chronosequence Stratigrapgy of Offshore Sabah and Sarawak, NW Borneo, Malaysia:a Unified Scheme Based on Graphic Correlation.Bulletin of the Geological Society of Malaysia, 57:39-46. Kuang, Z.G., Zhong, G.F., Wang, L.L., et al., 2014.Channel-Related Sediment Waves on the Eastern Slope Offshore Dongsha Islands, Northern South China Sea.Journal of Asian Earth Sciences, 79(2):540-551.https://doi.org/10.1016/j.jseaes.2012.09.025 http://d.old.wanfangdata.com.cn/Conference/8878023 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 http://www.sciencedirect.com/science/article/pii/026481728690053X Kvalstad, T.J., Andresen, L., Forsberg, C.F., et al.2005.The Storegga Slide:Evaluation of Triggering Sources and Slide Mechanics.Marine and Petroleum Geology, 22(1/2):245-256.https://doi.org/10.1016/j.marpetgeo.2004.10.019 http://www.sciencedirect.com/science/article/pii/S0264817204001941 Li, Q.Y., Zhao, Q.H., Zhong, G.F., et al., 2008.Deep Water Ventilation and Stratification in the Neogene South China Sea.Earth Science, 33(1):1-11 (in Chinese with English abstract). http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=dqkx200801001 Locat, J., Lee, H.J., 2002.Submarine Landslides:Advances and Challenges.Canadian Geotechnical Journal, 39(1):193-212. https://doi.org/10.1139/t01-089 Luan, X.W., Peng, X.C., Qiu, Y., 2009.Tectonic Control on the Formation of High-Deposition-Rate Sediment Drift in the Northern Slope of the South China Sea.Geoscience, 23(2):183-199 (in Chinese with English abstract). http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=xddz200902001 Luan, X.W., Peng, X.C., Wang, Y.M., et al., 2010.Activity and Formation of Sand Waves on Northern South China Sea Shelf.Journal of Earth Science, 21(1):55-70. https://doi.org/10.1007/s12583-010-0005-4 Pautot, G., Rangin, C., Briais, A., et al., 1986.Spreading Direction in the Central South China Sea.Nature, 321(8):150-154.https://doi.org/10.1038/321150a0 doi: 10.1038/321150a0 Piper, D.J.W., Cochonat, P., Morrison, M.L., 1999.The Sequence of Events around the Epicentre of the 1929 Grand Banks Earthquake:Initiation of Debris Flows and Turbidity Currents Inferred from Sidescan Sonar.Sedimentology, 46(1):79-97. https://doi.org/10.1046/j.1365-3091.1999.00204.x Rao, G., Cheng, Y.L., Lin, A.M., et al., 2017.Relationship Between Landslides and Active Normal Faulting in the Epicental Area of the AD 1 556 M~8.5 Huaxian Earthquake, SE Weihe Graben (Central China).Journal of Earth Science, 28(3):545-554.https://doi.org/10.1007/s12583-017-0900-z Schlüter, H.U., Hinz, K., Block, M., 1996.Tectono-Stratigraphic Terranes and Detachment Faulting of the South China Sea and Sulu Sea.Marine Geology, 130(1-2):39-78. https://doi.org/10.1016/0025-3227(95)00137-9 Shao, L., Li, X.J., Geng, J.H., et al., 2007.Deep-Water Bottom Current Deposition.Science in China (Series D), 37(6):771-777 (in Chinese). http://d.old.wanfangdata.com.cn/Periodical/zgkx-ed200707011 Sultan, N., Cochonat, P., Canals, M., et al., 2004.Triggering Mechanisms of Slope Instability Processes and Sediment Failure on Continental Margins:A Geotechnical Approach.Marine Geology, 213(1-4):291-321. https://doi.org/10.1016/j.margeo.2004.10.011 Taylor, B., Hayes, D.E., 1980.The Tectonic Evolution of the South China Basin.In:Hayes, D.E., ed., Tectonic and Geologic Evolution of Southeast Asian Seas and Islands.American Geophysical Union Geophysical Monograph, 23:89-104. Taylor, B., Hayes, D.E., 1983.Origin and History of the South China Sea Basin.In:Hayes, D.E., ed., The Tectonic and Geologic Evolution of Southeast Asia Seas Islands:Part 2.American Geophysical Union Geophysical Monograph, 27:23-56. Tian, Y.Y., Xu, C., Xu, X.W., et al., 2016.Detailed Inventory Mapping and Spatial Analysis to Landslides Induced by the 2013 Ms 6.6 Minxian Earthquake of China.Journal of Earth Science, 27(6):1016-1026.https://doi.org/10.1007/s12583-016-0905-z Wan, S.M., Li, A.C., Xu, K.H., et al., 2008.Characteristics of Clay Minerals in the Northern South China Sea and Its Implications for Evolution of East Asian Monsoon since Miocene.Earth Science, 33(3):289-300 (in Chinese with English abstract). Wang, H.R., Wang, Y.M., Qiu, Y., et al., 2007.Sediment Waves of the Deep-Water Environment in the Northern Continental Margin of the South China Sea.Progress in Natural Science, 17(9):1235-1243 (in Chinese). Wang, H.R., Wang, Y.M., Qiu, Y., et al., 2008.Development and Its Tectonic Activity's Origin of Turbidity Current Sediment Wave in Manila Trench, the South China Sea.Acta Sedimentologica Sinica, 26(1):39-45 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-CJXB200801004.htm Wynn, R.B., Stow, D.A.V., 2002a.Introduction to the Special Issue:Recognition and Interpretation of Deep-Water Sediment Waves-Implications for Palaeoceanography, Hydrocarbon Exploration and Flow Process Interpretation.Marine Geology, 192(1-3):1-3.https://doi.org/10.1016/s0025-3227(02)00546-7 doi: 10.1016/S0025-3227(02)00546-7 Wynn, R.B., Stow, D.A.V., 2002b.Classification and Characterisation of Deep-Water Sediment Waves.Marine Geology, 192(1-3):7-22.https://doi.org/10.1016/s0025-3227(02)00547-9 doi: 10.1016/S0025-3227(02)00547-9 Wynn, R.B., Weaver, P.P.E., Ercilla, G., et al., 2000.Sedimentary Processes in the Selvage Sediment-Wave Field, NE Atlantic:New Insights into the Formation of Sediment Waves by Turbidity Currents.Sedimentology, 47(6):1181-1197. https://doi.org/10.1046/j.1365-3091.2000.00348.x Xu, C., Xu, X.W., Tian, Y.Y., et al., 2016.Two Comparable Earthquakes Produced Greatly Different Coseismic Landslides:The 2015 Gorha, Nepal and 2008 Wenchuan, China Event.Journal of Earth Science, 27(6):1008-1015. https://doi.org/10.1007/s12583-016-0684-6 Yin, S.R., Wang, L.L., Guo, Y.Q., et al., 2015.Geomorphic Sedimentary Characteristics and Origin of the Dongsha Submarine Canyon.Science in China(Series D), 45(3):275-289 (in Chinese). http://www.cnki.com.cn/Article/CJFDTotal-JDXG201506012.htm 陈慧, 解习农, 毛凯楠, 2015.南海北缘一统暗沙附近深水等深流沉积体系特征.地球科学, 40(4):733-743.https://doi.org/10.3799/dqkx.2015.061 http://earth-science.net/WebPage/Article.aspx?id=3061 丁巍伟, 李家彪, 韩喜球, 等, 2010.南海东北部海底沉积物波的形态、粒度特征及物源、成因分析.海洋学报, 32(2):96-105. http://d.old.wanfangdata.com.cn/Periodical/hyxb201002011 高振中, 何幼斌, 罗顺社, 等, 1996.深水牵引流沉积-内潮汐、内波和等深流沉积研究.北京:科学出版社, 1-46. 李前裕, 赵泉鸿, 钟广法, 等, 2008.新近纪南海深层水的增氧与分层.地球科学, 33(1):1-11. http://earth-science.net/WebPage/Article.aspx?id=1726 栾锡武, 彭学超, 邱燕, 2009.南海北部陆坡高速堆积体的构造成因.现代地质, 23(2):183-199. doi: 10.3969/j.issn.1000-8527.2009.02.001 邵磊, 李学杰, 耿建华, 等, 2007.南海北部深水底流沉积作用.中国科学(D辑), 37(6):771-777. http://d.old.wanfangdata.com.cn/Periodical/zgkx-cd200706008 万世明, 李安春, 胥可辉, 等, 2008.南海北部中新世以来粘土矿物特征及东亚古季风记录.地球科学, 33(3):289-300. doi: 10.3321/j.issn:1000-2383.2008.03.001 王海荣, 王英民, 邱燕, 等, 2007.南海北部大陆边缘深水环境的沉积物波.自然科学进展, 17(9):1235-1243. doi: 10.3321/j.issn:1002-008x.2007.09.012 王海荣, 王英民, 邱燕, 等, 2008.南海东北部台湾浅滩陆坡的浊流沉积物波的发育及其成因的构造控制.沉积学报, 26(1):39-45. http://d.old.wanfangdata.com.cn/Periodical/cjxb200801005 殷绍如, 王嘹亮, 郭依群, 等, 2015.东沙海底峡谷的地貌沉积特征及成因.中国科学(D辑), 45(3):275-289. http://www.cnki.com.cn/Article/CJFDTOTAL-JDXK201503003.htm