Geomorphological Characteristics and Formation Mechanisms of Large Pockmarks in the Baiyun Submarine Channel System, Northern South China Sea

Abstract

Hydrothermal vents and pockmarks in the global ocean are direct evidence for extensive seabed fluid emission and fluid seepage. Pockmarks are seafloor crater-like depressions associated with fluid escape from the seabed and are considered to contribute to the transfer of methane into the ocean and ultimately into the atmosphere. In the South China Sea, several-meters to kilometer-scale pockmarks lie in different sedimentary basins around the continental margin and are related to local subsurface structures such as mud diapirs, gas chimneys, mud volcanoes and faults. The formation of pockmarks in the Baiyun submarine channel system was accompanied with the evolution of unidirectional migrating channels in the Pear River Mouth Basin (PRMB) that produced and developed under the interaction between downslope turbidity currents and along-slope bottom currents since the Middle Miocene. Based on new acquisitioned multibeam bathymetry and sub-bottom profiler data in the Baiyun submarine channel system in the PRMB, twelve large pockmarks with 500–1 500 m long, 200–900 m wide and 10–30 m deep are recognized on the top of inter-channel ridges (ICRs) in the Baiyun submarine channel system. These pockmarks in the channel system indicate mainly circular, elliptical, crescent-shaped, elongated and horseshoe shaped in the plan view. The crescent-shaped depressions at the head part of channels and the ‘pond-like’ depressions between the individual channel are found and interpreted from slope variations of the bathymetry data. We proposed that channel-related pockmarks occurred at the ICRs were produced by the upward migration of overpressure gas and fluid along gas chimneys and faults caused by the gas hydrate dissolution in the deep reservoirs since the Middle Miocene and the ICRs underwent the collapse and erosion process by bottom currents in the shallow part. The sources of fluid and gas induced to the formation of pockmarks are from deep to shallow reservoirs in the submarine channel system.

Keywords

pockmarks / inter-channel ridge / fluid migration / Baiyun submarine channel system / multibeam bathymetry data / sub-bottom profiler / South China Sea / submarine geology / geophysics

References

[1] Bai Y, Song H B, Guan Y X, et al. . Structural Characteristics and Genesis of Pockmarks in the Northwest of the South China Sea Derived from Reflective Seismic and Multibeam Data. Chinese Journal of Geophysics, 2014, 57(7): 2208-2222(in Chinese with English Abstract)

[2] Barckhausen U, Roeser H A, et al. Clift P, Kuhnt W, Wang P, et al. . Seafloor Spreading Anomalies in South China Sea Revisited. Continent-Ocean Interactions within East Asian Marginal Seas, 2004, Washington, DC. AGU: 121-125 149

[3] Bian C W, Ruan X D, Wang H N, et al. . Internal Solitary Waves Enhancing Turbulent Mixing in the Bottom Boundary Layer of Continental Slope. Journal of Marine Systems, 2022, 236: 103805

[4] Boetius A, Wenzhöfer F. Seafloor Oxygen Consumption Fuelled by Methane from Cold Seeps. Nature Geoscience, 2013, 6(9): 725-734

[5] Böttner C, Berndt C, Reinardy B T I, et al. . Pockmarks in the Witch Ground Basin, Central North Sea. Geochemistry, Geophysics, Geosystems, 2019, 20(4): 1698-1719

[6] Briais A, Patriat P, Tapponnier P. 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, 1993, 98(B4): 6299-6328

[7] Cauquil E, Stephane L, George R A, et al. . HighResolution Autonomous Underwater Vehicle (AUV) Geophysical Survey of a Large, Deep Water Pockmark Offshore Nigeria. 65th EAGE Conference & Exhibition, European Association of Geoscientists & Engineers, Stavanger, 2003,

[8] Chen D X, Wang X J, Völker D, et al. . Three Dimensional Seismic Studies of Deep-Water Hazard-Related Features on the Northern Slope of South China Sea. Marine and Petroleum Geology, 2016, 77: 1125-1139

[9] Chen D X, Wu S G, Dong D D, et al. . Focused Fluid Flow in the Baiyun Sag, Northern South China Sea: Implications for the Source of Gas in Hydrate Reservoirs. Chinese Journal of Oceanology and Limnology, 2013, 31(1): 178-189

[10] Chen D X, Zhang G X, Wang X J, et al. . Seismic Features and Origin of Fluid Escape Pipes Offshore Hainan Island on the Northern Slope of South China Sea. Marine and Petroleum Geology, 2021, 133: 105276

[11] Chen J X, Guan Y X, Song H B, et al. . Distribution Characteristics and Geological Implications of Pockmarks and Mud Volcanoes in the Northern and Western Continental Margin of the South China Sea. Chinese Journal of Geophysics, 2015, 58(3): 919-938(in Chinese with English Abstract)

[12] Chen J X, Song H B, Guan Y X, et al. . Morphologies, Classification and Genesis of Pockmarks, Mud Volcanoes and Associated Fluid Escape Features in the Northern Zhongjiannan Basin, South China Sea. Deep Sea Research Part II: Topical Studies in Oceanography, 2015, 122: 106-117

[13] Chen J X, Song H B, Guan Y X, et al. . Geological and Oceanographic Controls on Seabed Fluid Escape Structures in the Northern Zhongjiannan Basin, South China Sea. Journal of Asian Earth Sciences, 2018, 168: 38-47

[14] Chen S C, Hsu S K, Tsai C H, et al. . Gas Seepage, Pockmarks and Mud Volcanoes in the near Shore of SW Taiwan. Marine Geophysical Researches, 2010, 31(1): 133-147

[15] Chen X Q, Zhu J J, Zhu Q L, et al. . Fine Processing and Analysis of Multibeam Bathymetric Data Outlier from Surveying and Mapping in the South China Sea. Earth Science, 2025, 50(2): 535-550 in Chinese with English Abstract)

[16] Chiang C S, Yu H S. Morphotectonics and Incision of the Kaoping Submarine Canyon, SW Taiwan Orogenic Wedge. Geomorphology, 2006, 80(3/4): 199-213

[17] Clift P, Lin J. Preferential Mantle Lithospheric Extension under the South China Margin. Marine and Petroleum Geology, 2001, 18(8): 929-945

[18] Cohen J K, Stockwell J W. CWP/SU: Seismic Un*x Release No. 42: An Open Source Software Package for Seismic Research and Processing, 2010, Golden, Colorado. Center for Wave Phenomena, Colorado School of Mines

[19] Cole D, Stewart S A, Cartwright J A. Giant Irregular Pockmark Craters in the Palaeogene of the Outer Moray Firth Basin, UK North Sea. Marine and Petroleum Geology, 2000, 17(5): 563-577

[20] Coughlan M, Roy S, O’Sullivan C, et al. . Geological Settings and Controls of Fluid Migration and Associated Seafloor Seepage Features in the North Irish Sea. Marine and Petroleum Geology, 2021, 123: 104762

[21] Crémière A, Chand S, Sahy D, et al. . Structural Controls on Seepage of Thermogenic and Microbial Methane since the Last Glacial Maximum in the Harstad Basin, Southwest Barents Sea. Marine and Petroleum Geology, 2018, 98: 569-581

[22] Cronin B Tthe Jubilee Team, Tullow Ghana Limited. Giant Pockmark-Initiated Deep-Water Slope Channel Complexes. AAPG Bulletin, 2022, 106(4): 829-868

[23] Dandapath S, Chakraborty B, Karisiddaiah S M, et al. . Morphology of Pockmarks along the Western Continental Margin of India: Employing Multibeam Bathymetry and Backscatter Data. Marine and Petroleum Geology, 2010, 27(10): 2107-2117

[24] Davy B, Pecher I, Wood R, et al. . Gas Escape Features off New Zealand: Evidence of Massive Release of Methane from Hydrates. Geophysical Research Letters, 2010, 37(21): 2010GL045184

[25] Di P F, Huang H G, Huang B J, et al. . Seabed Pockmark Formation Associated with Mud Diapir Development and Fluid Activities in the Yinggehai Basin of the South China Sea. Journal of Tropical Oceanography, 2012, 31(5): 26-36(in Chinese with English Abstract)

[26] Dimitrov L, Woodside J. Deep Sea Pockmark Environments in the Eastern Mediterranean. Marine Geology, 2003, 195(1/2/3/4): 263-276

[27] Ding W W, Li J B, Li J, et al. . Morphotectonics and Evolutionary Controls on the Pearl River Canyon System, South China Sea. Marine Geophysical Research, 2013, 34(3): 221-238

[28] Dondurur D. Acquisition and Processing of Marine Seismic Data, 2018, Amsterdam, Netherlands. Elsevier Inc.

[29] Fader G B J. Gas-Related Sedimentary Features from the Eastern Canadian Continental Shelf. Continental Shelf Research, 1991, 11(8/9/10): 1123-1153

[30] Fan Q, Zhu Z Y, Pang W X, et al. . Reservoir Characteristics and Exploration Implications of Gas Hydrate Enrichment Area, Qiongdongnan Basin. Earth Science, 2024, 49(4): 1421-1430(in Chinese with English Abstract)

[31] Feng DChen D F, Feng D. A History of South China Sea Hydrocarbon Seep Research. South China Sea Seeps, 2023, Singapore. Springer Nature Singapore: 1-12

[32] Foland S, Maher N, Yun J W. Pockmarks along the Californian Continental Margin: Implications for Fluid Flow. AAPG Bulletin, 1999, 83: 681-706

[33] Foucher J P, Westbrook G, Boetius A, et al. . Structure and Drivers of Cold Seep Ecosystems. Oceanography, 2009, 22(1): 92-109

[34] Gay A, Lopez M, Cochonat P, et al. . Sinuous Pockmark Belt as Indicator of a Shallow Buried Turbiditic Channel on the Lower Slope of the Congo Basin, West African Margin. In: Van Rensbergen, P., Hillis, R. R., Maltman, A. J., et al., eds., Subsurface Sediment Mobilization. Geological Society of London, Special Publications, 2003, 216: 173-189

[35] Gay A, Lopez M, Cochonat P, et al. . Evidences of Early to Late Fluid Migration from an Upper Miocene Turbiditic Channel Revealed by 3D Seismic Coupled to Geochemical Sampling within Seafloor Pockmarks, Lower Congo Basin. Marine and Petroleum Geology, 2006, 23(3): 387-399

[36] Gay A, Lopez M, Ondreas H, et al. . Seafloor Facies Related to Upward Methane Flux within a Giant Pockmark of the Lower Congo Basin. Marine Geology, 2006, 226(1/2): 81-95

[37] GEBCO Compilation Group. GEBCO_2022 Grid, 2022,

[38] Geng M H, Song H B, Guan Y X, et al. . Sill-Related Seafloor Domes in the Zhongjiannan Basin, Western South China Sea. Marine and Petroleum Geology, 2020, 122: 104669

[39] Gong C L, Wang Y M, Zhu W L, et al. . Upper Miocene to Quaternary Unidirectionally Migrating Deep-Water Channels in the Pearl River Mouth Basin, Northern South China Sea. AAPG Bulletin, 2013, 97(2): 285-308

[40] Hao F, Li S T, Gong Z S. Thermal Regime, Interreservoir Compositional Heterogeneities, and Reservoir-Filling History of the Dongfang Gas Field, Yinggehai Basin, South China Sea: Evidence for Episodic Fluid Injections in Overpressured Basins. AAPG Bulletin, 2000, 84(5): 607-626

[41] Harrington P K. Formation of Pockmarks by Pore-Water Escape. Geo-Marine Letters, 1985, 5(3): 193-197

[42] Hasiotis T, Papatheodorou G, Kastanos N, et al. . A Pockmark Field in the Patras Gulf (Greece) and Its Activation during the 14/7/93 Seismic Event. Marine Geology, 1996, 130(3/4): 333-344

[43] He Y, Zhong G F, Wang L L, et al. . Characteristics and Occurrence of Submarine Canyon-Associated Landslides in the Middle of the Northern Continental Slope, South China Sea. Marine and Petroleum Geology, 2014, 57: 546-560

[44] Henkart P. Chirp Sub-Bottom Profiler Processing: A Review. Sea Technology, 2006, 10: 35-38

[45] Hill J C, Driscoll N W, Weissel J K, et al. . Large-Scale Elongated Gas Blowouts along the U.S. Atlantic Margin. Journal of Geophysical Research: Solid Earth, 2004, 109(B9): 2004JB002969

[46] Hovland M. Characteristics of Pockmarks in the Norwegian Trench. Marine Geology, 1981, 39(1/2): 103-117

[47] Hovland M. Elongated Depressions Associated with Pockmarks in the Western Slope of the Norwegian Trench. Marine Geology, 1983, 51(1/2): 35-46

[48] Hovland M. On the Self-Sealing Nature of Marine Seeps. Continental Shelf Research, 2002, 22(16): 2387-2394

[49] Hovland M, Heggland R, De Vries M H, et al. . UnitPockmarks and Their Potential Significance for Predicting Fluid Flow. Marine and Petroleum Geology, 2010, 27(6): 1190-1199

[50] Hovland M, Judd A G. Seabed Pockmarks and Seepages, 1988, London. Graham and Trotman: 293

[51] Hovland M, Judd A G, King L H. Characteristic Features of Pockmarks on the North Sea Floor and Scotian Shelf. Sedimentology, 1984, 31(4): 471-480

[52] Hovland M, Sommerville J H. Characteristics of Two Natural Gas Seepages in the North Sea. Marine and Petroleum Geology, 1985, 2(4): 319-326

[53] Hovland M, Svensen H, Forsberg C F, et al. . Complex Pockmarks with Carbonate-Ridges off Mid-Norway: Products of Sediment Degassing. Marine Geology, 2005, 218(1/2/3/4): 191-206

[54] Huang Y-S, Hsu S K, Su C C, et al. . Shallow Gas Hydrates off Southwest Taiwan and Their Mechanisms. Marine Geophysical Research, 2021, 42: 7

[55] Intergovernmental Panel on Climate Change (IPCC). Climate Change 2001: The Scientific Basis, 2001, Cambridge. Cambridge University Press: 881

[56] Jenness, J., 2013. DEM Surface Tools. Jenness Enterprises. [20257-20]. http://www.jennessent.com/arcgis/surface_area.htm

[57] Jobe Z R, Lowe D R, Uchytil S J. Two Fundamentally Different Types of Submarine Canyons along the Continental Margin of Equatorial Guinea. Marine and Petroleum Geology, 2011, 28(3): 843-860

[58] Jones A T, Greinert J, Bowden D A, et al. . Acoustic and Visual Characterisation of Methane-Rich Seabed Seeps at Omakere Ridge on the Hikurangi Margin, New Zealand. Marine Geology, 2010, 272(1/2/3/4): 154-169

[59] Josenhans H W, King L H, Fader G B. A Side-Scan Sonar Mosaic of Pockmarks on the Scotian Shelf. Canadian Journal of Earth Sciences, 1978, 15(5): 831-840

[60] Judd A G. Computerised Marine Geophysical and Geotechnical Mapping Techniques and Their Application to a Study of Pockmarks, 1982, Tyne. University of Newcastle: 233

[61] Judd A G. 2001 Strategic Environmental Assessment SEA2 Technical Report: Pockmarks in the UK Sector of the North Sea, 2001,

[62] Judd A G, Hovland M. Seabed Fluid Flow: The Impact on Geology, Biology, and the Marine Environment, 2007, Cambridge. Cambridge University Press

[63] Judd A G, Hovland M, Dimitrov L I, et al. . The Geological Methane Budget at Continental Margins and Its Influence on Climate Change. Geofluids, 2002, 2(2): 109-126

[64] Judd A G, Long D, Sankey M. Pockmark Formation and Activity, U. K. Block 15/25, North Sea. Bulletin of the Geological Society of Denmark, 1994, 41: 34-49

[65] Kelley J T, Dickson S M, Belknap D F, et al. . Giant SeaBed Pockmarks: Evidence for Gas Escape from Belfast Bay, Maine. Geology, 1994, 22(1): 59

[66] King L H, MacLean B. Pockmarks on the Scotian Shelf. Geological Society of America Bulletin, 1970, 81(10): 3141

[67] Koch S, Berndt C, Bialas J, et al. . Gas-Controlled Seafloor Doming. Geology, 2015, 43(7): 571-574

[68] Kvenvolden K A, Rogers B W. Gaia’s Breath—Global Methane Exhalations. Marine and Petroleum Geology, 2005, 22(4): 579-590

[69] Li D. Geologic Evolution of Petroliferous Basins on Continental Shelf of China. AAPG Bulletin, 1984, 68: 993-1003

[70] Li H, Wang Y M, Zhu W L, et al. . Seismic Characteristics and Processes of the Plio-Quaternary Unidirectionally Migrating Channels and Contourites in the Northern Slope of the South China Sea. Marine and Petroleum Geology, 2013, 43: 370-380

[71] Li L, Song H B, Yang J X. A Preliminary Study of Seafloor Gas Seepage in Central Sag Zone of Yinggehai Basin. Progress in Geophysics, 2006, 21(4): 1244-1247(in Chinese with English Abstract)

[72] Li P L, Rao C T. Tectonic Characteristics and Evolution History of the Pearl River Mouth Basin. Tectonophysics, 1994, 235(1/2): 13-25

[73] Li S J, Chu F Y, Fang Y X, et al. . Associated Interpretation of Sub-Bottom and Single-Channel Seismic Profiles from Slope of Shenhu Area in the Northern South China Sea— Characteristics of Gas Hydrate Sediment. Journal of Tropical Oceanography, 2010, 29(4): 56-62(in Chinese with English Abstract)

[74] Li S T, Lin C S, Zhang Q M, et al. . Episodic Rifting of Continental Marginal Basins and Tectonic Events since 10 Ma in the South China Sea. Chinese Science Bulletin, 1999, 44(1): 10-23

[75] Liu C L, Ye Y G, Meng Q G, et al. . The Characteristics of Gas Hydrates Recovered from Shenhu Area in the South China Sea. Marine Geology, 2012, 307–310: 22-27

[76] Liu H. Geodynamic Scenario and Structural Styles of Mesozoic and Cenozoic Basins in China. AAPG Bulletin, 1986, 70: 377-395

[77] Liu J, Peng G R, Zhang L L, et al. . Genesis and Types of Buried Hills in the Tectonic Setting of the Inheriting Continental Margin in Baiyun Sag, Northern South China Sea. Earth Science, 2025, 50(2): 405-418(in Chinese with English Abstract)

[78] Liu X J, Tang D H, Yan P, et al. . Characteristics of Authigenic Carbonates from a Mega-Pockmark on the Eastern Side of Baiyun Sag, South China Sea and Their Geological Significance. Marine Geology & Quaternary Geology, 2017, 37(6): 119-127(in Chinese with English Abstract)

[79] Lu Y T, Li W, Wu S G, et al. . Morphology, Architecture, and Evolutionary Processes of the Zhongjian Canyon between Two Carbonate Platforms, South China Sea. Interpretation, 2018, 6(4): SO1-SO15

[80] Lu Y T, Xu X Y, Luan X W, et al. . Morphology, Internal Architectures, and Formation Mechanisms of Mega-Pockmarks on the Northwestern South China Sea Margin. Interpretation, 2021, 9(4): T1039-T1054

[81] Luo M, Chen L Y, Wang S H, et al. . Pockmark Activity Inferred from Pore Water Geochemistry in Shallow Sediments of the Pockmark Field in Southwestern Xisha Uplift, Northwestern South China Sea. Marine and Petroleum Geology, 2013, 48: 247-259

[82] Lüdmann T, Wong H K. Neotectonic Regime on the Passive Continental Margin of the Northern South China Sea. Tectonophysics, 1999, 311: 113-138

[83] Ma B J, Wu S G, Sun Q L, et al. . The Late Cenozoic Deep-Water Channel System in the Baiyun Sag, Pearl River Mouth Basin: Development and Tectonic Effects. Deep Sea Research Part II: Topical Studies in Oceanography, 2015, 122: 226-239

[84] Marcon Y, Ondréas H, Sahling H, et al. . Fluid Flow Regimes and Growth of a Giant Pockmark. Geology, 2014, 42(1): 63-66

[85] Maritime K. Kongsberg EM122 Multibeam Echo Sounder Maintenance Manual, 2009,

[86] Moss J L, Cartwright J. 3D Seismic Expression of Km-Scale Fluid Escape Pipes from Offshore Namibia. Basin Research, 2010, 22(4): 481-501

[87] Newman K R, Cormier M H, Weissel J K, et al. . Active Methane Venting Observed at Giant Pockmarks along the U.S. Mid-Atlantic Shelf Break. Earth and Planetary Science Letters, 2008, 267(1/2): 341-352

[88] Ondréas H, Olu K, Fouquet Y, et al. . ROV Study of a Giant Pockmark on the Gabon Continental Margin. Geo-Marine Letters, 2005, 25: 281-292

[89] Ou X L, Zhu J J, Li S Z, et al. . Submarine Geomorphological Features and Their Origins Analyzed from Multibeam Bathymetry Data in the South China Sea. Journal of Marine Science and Engineering, 2021, 9: 1419

[90] Palan K, Green A N, Andrews B, et al. . A Morphometric Analysis of the Fluid Flow Features of the Southern Orange Basin, South Africa. Marine Geology, 2020, 423: 106145

[91] Pape T, Bünz S, Hong W L, et al. . Origin and Transformation of Light Hydrocarbons Ascending at an Active Pockmark on Vestnesa Ridge, Arctic Ocean. Journal of Geophysical Research: Solid Earth, 2020, 125: e2018JB016679

[92] Paull C K, Ussler WIIIHolbrook W S, et al. . Origin of Pockmarks and Chimney Structures on the Flanks of the Storegga Slide, Offshore Norway. Geo-Marine Letters, 2008, 28(1): 43-51

[93] Paull C, Ussler WIIIMaher N, et al. . Pockmarks off Big Sur, California. Marine Geology, 2002, 181(4): 323-335

[94] Pilcher R, Argent J. Mega-Pockmarks and Linear Pockmark Trains on the West African Continental Margin. Marine Geology, 2007, 244(1/2/3/4): 15-32

[95] Qiu Y, Nie X, Yan P, et al. . Zhongnan-Liyue Fault Zone Developed at Continental Margins of the South China Sea and Tectonic Movements. Earth Science, 2024, 49(10): 3471-3487(in Chinese with English Abstract)

[96] Riboulot V, Sultan N, Imbert P, et al. . Initiation of GasHydrate Pockmark in Deep-Water Nigeria: Geo-Mechanical Analysis and Modelling. Earth and Planetary Science Letters, 2016, 434: 252-263

[97] Ru K, Pigott J D. Episodic Rifting and Subsidence in the South China Sea. American Association of Petroleum Geologists Bulletin, 1986, 70(9): 1136-1155

[98] Serié C, Huuse M, Schødt N H. Gas Hydrate Pingoes: Deep Seafloor Evidence of Focused Fluid Flow on Continental Margins. Geology, 2012, 40(3): 207-210

[99] Sha Z, Yang M, Liang J, et al. . The Characteristics of the Abnormal Physiognomys of Seabed Related to Gas Hydrate in North Slope, South China Sea. Geological South China Sea, 2003, 14: 29-34(in Chinese with English Abstract)

[100] Shang J, Wu L, Liang J, et al. . The Microtopographic Features and Gas Seep Model on the Slope in the Northeastern South China Sea. Marine Geology & Quaternary Geology, 2014, 34(1): 129-136(in Chinese with English Abstract)

[101] Sinquin J M, Vrignaud C, Mathieu G. DORIS Software: A Tool to Process Sound Velocity Profiles, 2016,

[102] Soter S. Macroscopic Seismic Anomalies and Submarine Pockmarks in the Corinth-Patras Rift, Greece. Tectonophysics, 1999, 308(1/2): 275-290

[103] Stockwell J W. The CWP/SU: Seismic Un Package 1. Computers & Geosciences, 1999, 25(4): 415-419

[104] Su M, Yang R, Wang H, et al. . Gas Hydrates Distribution in the Shenhu Area, Northern South China Sea: Comparisons between the Eight Drilling Sites with Gas-Hydrate Petroleum System. Geologica Acta, 2016, 14: 79-100

[105] Suess E. Marine Cold Seeps and Their Manifestations: Geological Control, Biogeochemical Criteria and Environmental Conditions. International Journal of Earth Sciences, 2014, 103(7): 1889-1916

[106] Sultan N, Bohrmann G, Ruffine L, et al. . Pockmark Formation and Evolution in Deep Water Nigeria: Rapid Hydrate Growth versus Slow Hydrate Dissolution. Journal of Geophysical Research: Solid Earth, 2014, 119(4): 2679-2694

[107] Sultan N, Marsset B, Ker S, et al. . Hydrate Dissolution as a Potential Mechanism for Pockmark Formation in the Niger Delta. Journal of Geophysical Research: Solid Earth, 2010, 115(B8): 2010JB007453

[108] Sun Q L, Wu S G, Cartwright J, et al. . Shallow Gas and Focused Fluid Flow Systems in the Pearl River Mouth Basin, Northern South China Sea. Marine Geology, 2012, 315/316/317/318: 1-14

[109] Sun Q L, Wu S G, Hovland M, et al. . The Morphologies and Genesis of Mega-Pockmarks near the Xisha Uplift, South China Sea. Marine and Petroleum Geology, 2011, 28(6): 1146-1156

[110] Taylor B, Hayes D E. The Tectonic Evolution of the South China Basin. The Tectonic and Geologic Evolution of Southeast Asian Seas and Islands, 1980, Washington, D.C.. American Geophysical Union: 89-104

[111] Taylor B, Hayes D E. Origin and History of the South China Sea Basin. The Tectonic and Geologic Evolution of Southeast Asian Seas and Islands: Part 2, 1983, Washington, D.C.. American Geophysical Union: 23-56

[112] Van Weering T, Jansen J H F, Eisma D. Acoustic Reflection Profiles of the Norwegian Channel between Oslo and Bergen. Netherlands Journal of Sea Research, 1973, 6(1/2): 241-263

[113] von Deimling J, Hoffmann J, Geersen J, et al. . Millions of Seafloor Pits, Not Pockmarks, Induced by Vertebrates in the North Sea. Communications Earth & Environment, 2023, 4: 478

[114] Wan Z F, Zhang W, Ma C, et al. . Dissociation of Gas Hydrates by Hydrocarbon Migration and Accumulation-Derived Slope Failures: An Example from the South China Sea. Geoscience Frontiers, 2022, 13(2): 101345

[115] Wang C S, Zhu J J, Zhao D D, et al. . Origin and Evolution of Submarine Canyons. Marine Geology Frontiers, 2021, 37(3): 1-15(in Chinese with English Abstract)

[116] Wang H Q, Ding W W, Wang F. Evolution and Controlling Factors of Sedimentary Flux of East Asian Continental Margin since the Cenozoic. Earth Science, 2025, 50(9): 3559-3580(in Chinese with English Abstract)

[117] Wang S. Basic Geological Structural Features of the Basin at the Mouth of Pearl River. Acta Petrolei Sinica, 1982, (in Chinese with English Abstract)

[118] Wang T K, Chen M K, Lee C S, et al. . Seismic Imaging of the Transitional Crust across the Northeastern Margin of the South China Sea. Tectonophysics, 2006, 412(3/4): 237-254

[119] Wang Y L, Tu G H, Yu J H, et al. . Discovery of Pockmarks in the Zengmu Basin, Southern South China Sea and the Implication. Journal of Oceanology and Limnology, 2023, 41(2): 757-768

[120] Wei J G, Fang Y X, Lu H L, et al. . Distribution and Characteristics of Natural Gas Hydrates in the Shenhu Sea Area, South China Sea. Marine and Petroleum Geology, 2018, 98: 622-628

[121] Wei J G, Yang L, Liang Q Y, et al. . Geomechanical Properties of Gas Hydrate-Bearing Sediments in Shenhu Area of the South China Sea. Energy Reports, 2021, 7: 8013-8020

[122] Wessel P, Luis J F, Uieda L, et al. . The Generic Mapping Tools Version 6. Geochemistry, Geophysics, Geosystems, 2019, 20(11): 5556-5564

[123] Westbrook G K, Thatcher K, Rohling E, et al. . Escape of Methane Gas from the Seabed along the West Spitsbergen Continental Margin. Geophysics Research Letters, 2009, 36: L15608

[124] Wu L S, Yang S X, Liang J Q, et al. . Variations of Pore Water Sulfate Gradients in Sediments as Indicator for Underlying Gas Hydrate in Shenhu Area, the South China Sea. Science China Earth Sciences, 2013, 56(4): 530-540

[125] Wu T T, Wei J G, Liu S X, et al. . Characteristics and Formation Mechanism of Seafloor Domes on the North-Eastern Continental Slope of the South China Sea. Geological Journal, 2020, 55(1): 1-10

[126] Wu Z Y, Zhao D N, Zhou J Q, et al. . Formation Mechanism of Deep-Sea Giant Pockmarks: A Case Study of the Reed Basin in the South China Sea. Geomorphology, 2023, 433: 108726

[127] Yang H C, Tang H F, Ji M, et al. . Formation and Evolution of the Late Triassic Granite Buried Hill in the Songnan Low Uplift, Qiongdongnan Basin. Earth Science, 2025, 50(6): 2124-2143(in Chinese with English Abstract)

[128] Yang S X, Liang J Q, Lei Y, et al. . GMGS4 Gas Hydrate Drilling Expedition in the South China Sea. Fire in the Ice, 2017, 17(1): 7-11

[129] Yang S X, Zhang M, Liang J Q, et al. . Preliminary Results of China’s Third Gas Hydrate Drilling Expedition: A Critical Step from Discovery to Development in the South China Sea. Fire in the Ice, 2015, 15(2): 1-5

[130] Yao B C. The Tectonic Evolution and Sedimentary Basins of South China Sea in Cenozoic. Geological Research of South China Sea, 1998, 10: 1-11(in Chinese with English Abstract)

[131] Yao B C. The Three-Dimensional Structure of Lithosphere and Its Evolution in the South China Sea, 2006, Beijing. Geological Publishing House(in Chinese with English Abstract)

[132] Yilmaz O. Seismic Data Analysis: Processing, Inversion and Interpretation of Seismic Data, 2001, Tulsa. SEG

[133] Yu H Z, Huang C, Ku J W. Morphology and Possible Origin of the Kaoping Submarine Canyon Head of Southwest Taiwan. Acta Oceanographica Taiwanica, 1991, 27: 40-50

[134] Yu K Q, Miramontes E, Alves T M, et al. . Incision of Submarine Channels over Pockmark Trains in the South China Sea. Geophysical Research Letters, 2021, 48(24): e2021GL092861

[135] Zhang G, Yang S, Zhang M. GMGS2 Expedition Investigates Rich and Complex Gas Hydrate Environment in the South China Sea. Fire in the Ice, 2014, 14(1): 1-5

[136] Zhang H Q, Yang S X, Wu N Y, et al. . Successful and Surprising Results for China’s First Gas Hydrate Drilling Expedition. Fire in the Ice, 2007, 7: 6-9

[137] Zhang K, Guan Y X, Song H B, et al. . A Preliminary Study on Morphology and Genesis of Giant and Mega Pockmarks near Andu Seamount, Nansha Region (South China Sea). Marine Geophysical Research, 2020, 41(1): 2

[138] Zhang S Y, Zhu J J, Jia Y G, et al. . Submarine SmallScale Features of Cyclic Steps in the Penghu Canyon: Implications for the Migration of Canyon. Journal of Marine Science and Engineering, 2022, 10(9): 1301

[139] Zhang T S, Wu Z Y, Zhao D N, et al. . The Morphologies and Genesis of Pockmarks in the Reed Basin, South China Sea. Haiyang Xuebao, 2019, 41(3): 106-120(in Chinese with English Abstract)

[140] Zhang WChen D F, Feng D. Distribution, Variability of Seeps. South China Sea Seeps, 2023, Singapore. Springer Nature Singapore: 13-34

[141] Zhang W, Liang J Q, Wei J G, et al. . Geological and Geophysical Features of and Controls on Occurrence and Accumulation of Gas Hydrates in the First Offshore Gas-Hydrate Production Test Region in the Shenhu Area, Northern South China Sea. Marine and Petroleum Geology, 2020, 114: 104191

[142] Zhao J, Zhang L, Wang X Y, et al. . Characteristics of Paleontological Communities in Surface Sediments of the Southern South China Sea and Their Paleoclimatic and Paleoenvironmental Significance. Journal of Earth Science, 2024, 35(1): 144-154

[143] Zhou W, Wang Y M, Gao X Z, et al. . Architecture, Evolution History and Controlling Factors of the Baiyun Submarine Canyon System from the Middle Miocene to Quaternary in the Pearl River Mouth Basin, Northern South China Sea. Marine and Petroleum Geology, 2015, 67: 389-407

[144] Zhu J J, Li J, Sun Z X, et al. . Crustal Thinning and Extension in the Northwestern Continental Margin of the South China Sea. Geological Journal, 2016, 51(S1): 286-303

[145] Zhu J J, Qiu X L, Kopp H, et al. . Shallow Anatomy of a Continent-Ocean Transition Zone in the Northern South China Sea from Multichannel Seismic Data. Tectonophysics, 2012, 554–557: 18-29

[146] Zhu J J, Qiu X L, Xu H L, et al. . Seismic Reflection Characteristic and Structure Unit Division of a Continent-Ocean Transition Zone in the Northern South China Sea. Journal of Tropical Oceanography, 2012, 31(3): 28-34(in Chinese with English Abstract)

[147] Zhu J J, Xu H L, Qiu X L, et al. . Crustal Structure and Rifting of the Northern South China Sea Margin: Evidence from Shoreline-Crossing Seismic Investigations. Geological Journal, 2018, 53(5): 2065-2083

[148] Zhu M Z, Graham S, Pang X, et al. . Characteristics of Migrating Submarine Canyons from the Middle Miocene to Present: Implications for Paleoceanographic Circulation, Northern South China Sea. Marine and Petroleum Geology, 2010, 27(1): 307-319

[149] Zhu S, Li X J, Zhang H D, et al. . Types, Characteristics, Distribution, and Genesis of Pockmarks in the South China Sea: Insights from High-Resolution Multibeam Bathymetric and Multichannel Seismic Data. International Geology Review, 2021, 63(13): 1682-1702

RIGHTS & PERMISSIONS

China University of Geosciences (Wuhan) and Springer-Verlag GmbH Germany, Part of Springer Nature