Submarine Geomorphology (eBook)

Foreword 7
Acknowledgements 9
Contents 10
1 Introduction 13
1 Our Blue Planet 13
2 Submarine Geomorphology 14
3 History of Submarine Geomorphology 16
References 20
Data and Methods in Submarine Geomorphology 22
2 Sidescan Sonar 23
Abstract 23
1 History of Sonar 23
2 Principles of Sidescan Sonar 25
3 State of the Art 27
4 Strengths and Weaknesses 32
5 Future Developments 32
Acknowledgements 33
References 33
3 Multibeam Echosounders 35
Abstract 35
1 Introduction 35
1.1 Review and History 35
1.2 Current Uses in Submarine Geomorphology 36
2 Physical/Technical Principles of the Method 37
2.1 Imaging Geometry 37
2.2 Range Performance 39
2.3 Range Resolution 40
2.4 Angular Resolution 41
2.5 Bottom Detection 42
2.6 Sounding Density 43
3 Integrated Sensors 43
3.1 Vessel Reference Frame 44
3.2 Orientation 45
3.3 Horizontal Positioning 46
3.4 Vertical Positioning 46
3.5 Sound Speed 48
4 State of the Art Tools 48
5 Strength and Weaknesses of the Method for Investigating Submarine Geomorphology 49
6 Conclusions 50
References 51
4 Reflection and Refraction Seismic Methods 52
Abstract 52
1 History of Seismic Methods 53
2 Physical Principles 54
2.1 Basic Principles of the Seismic Reflection Method 54
2.2 Basic Principles of the Seismic Refraction Method 56
3 Survey Design and Processing 58
3.1 Seismic Reflection Surveys 58
3.1.1 Types of Marine Seismic Reflection Surveys 58
3.1.2 The Seismic Source 58
3.1.3 Receiver Arrays 59
3.1.4 Recording Parameters 59
3.1.5 Basic Processing Steps 59
3.2 Seismic Refraction Surveys 60
3.2.1 Acquisition Geometries 60
3.2.2 Receiver Types 60
3.2.3 Basic Processing Scheme 62
3.2.4 Forward and Inverse Modeling 63
4 State of the Art Tools and Methods 64
4.1 Overview 64
4.2 Parametric Single-Beam Echo-Sounding 64
4.3 Deep-Towed Seismic Acquisition 64
4.4 High-Resolution 3D Seismic Imaging 65
4.5 Broadband Imaging 66
4.6 Mirror Imaging of OBS Data 66
4.7 Joint Inversion of Refraction and Reflection Data 67
4.8 3D Full-Waveform Inversion of Wide-Angle, Multi-azimuth Data 68
5 Strengths and Weaknesses 68
Acknowledgements 69
References 69
5 Quantitative Analyses of Morphological Data 72
Abstract 72
1 Mapping Submarine Morphologies 72
2 Quantitative Structures, Shapes and Their Variations 74
3 Geostatistics to Geographical Information Systems 76
3.1 Basic Measurements 76
3.2 Variations with Spatial Scales 79
3.3 Finding Trends and Patterns 80
4 Conclusions 81
References 82
6 Seafloor Sediment and Rock Sampling 84
Abstract 84
1 Introduction 84
2 Surface Sediment Sampling 85
2.1 Dredging 85
2.2 Box Corer 85
2.3 Grab Sampler 85
2.4 ROV Push Cores 86
3 Shallow Sediment Coring 87
3.1 Gravity Corer 87
3.2 Piston Corer 89
3.3 Kasten Corer 90
3.4 Vibrocorer 90
3.5 Multi-corer and Mega Corer 92
3.6 Giant Piston Corer and the CALYPSO Corer 93
4 Seafloor Drilling 94
4.1 Oil and Gas Industry Operations 94
4.2 International Ocean Discovery Program 96
4.3 Seafloor Drill Rigs 98
5 Core Handling 99
References 100
7 ROVs and AUVs 102
Abstract 102
1 Method Descriptions 103
1.1 Remotely Operated Vehicles 103
1.2 Autonomous Underwater Vehicles 104
1.3 Using Robotic Vehicles to Study Seafloor Geomorphology 106
2 Different Applications of ROVs and AUVs for Geomorphological Studies 107
2.1 High-Resolution Multibeam Bathymetry 107
2.2 True 3-Dimensional Morphology 108
2.3 Sidescan and Synthetic Aperture Sonar 110
2.4 Photomosaicking and Photogrammetry 110
2.5 Laser Line Scan 111
3 Future Directions 113
Acknowledgements 113
References 114
Submarine Landforms and Processes 118
8 Origin and Geomorphic Characteristics of Ocean Basins 119
Abstract 119
1 Introduction 119
1.1 Definition of Terms—Ocean Basins and Bathymetric Basins 120
1.2 Tectonic Origin of Ocean Basins 121
1.3 Multiple Origins of Bathymetric Ocean Basins 123
1.4 Aims of This Study 124
2 Methods 125
3 Results 126
4 Discussion 129
4.1 Key Drivers of Basin Evolution 129
4.2 Seamount Frequency of Occurrence and Sediment Thickness 135
4.3 Geomorphology and Global Bottom Water Circulation 137
5 Conclusions 140
Acknowledgements 141
References 141
9 Drivers of Seafloor Geomorphic Change 143
Abstract 143
1 Introduction 143
2 Plate Tectonics—Continental Break-up and Fate of the Oceanic Lithosphere at Convergent Plate Boundaries 145
2.1 Oceanic Spreading Centres 145
2.2 Transform Faults and Fracture Zones 146
2.3 Subduction Zones 146
2.4 Volcanic Islands 146
3 Sediment Types 148
3.1 Terrigenous Sediments (Also: Lithogenous) 148
3.2 Biogenic Sediments (Also: Biogenous) 148
3.3 Authigenic Sediments (Also: Hydrogenous) 149
3.4 Volcanogenic Sediments 149
3.5 Cosmogenous Sediments 149
3.6 Plastics 149
4 Gravity—Density Currents, Slope Instability and Mass Transport Deposits 150
4.1 The Ocean as a Sediment Sink 150
4.2 Density Currents, Erosion, Transport and Deposition 150
4.3 Submarine Slope Instability and Mass-Transport Deposits 152
5 Ice–Ice Bull-Dozing Effect from Land to the Sea on Polar Continental Margins 153
5.1 Ice Streams 153
5.2 Ice Grounding at the Continental Shelf Edge 155
5.3 Ice Retreating During Deglaciations 155
6 Compaction Disequilibrium—Pore Fluids Overpressure in Marine Sedimentary Sequences 156
7 Oceanic Circulation, Waves and Tides, and Sea Level Change 158
7.1 Bottom Currents 158
7.2 Waves and Tides 160
7.3 Sea Level Change 160
8 Chemical Precipitation/Dissolution and Bioconstructions 161
8.1 Methane-Derived Carbonate Precipitation 162
8.2 Weathering at Hydrothermal Vents 162
8.3 Salt Deformation 164
8.4 Submarine Karst 164
8.5 Benthic Organisms 165
9 Human Activity 166
Suggested Reading 166
Section 2 166
Section 3 166
Section 4 167
Section 5 167
Section 6 167
Section 7 167
Section 8 167
Section 9 167
10 Shallow Coastal Landforms 168
Abstract 168
1 Introduction 168
2 Depositional Shallow Coastal Landforms 171
2.1 Ripples, Dunes, Sand Waves and Antidunes 171
2.2 Sand Ribbons, Sand Patches, Sand Banks 174
3 Erosional Shallow Coastal Landforms 176
3.1 Scours Produced by Vortex Flow: Flute Marks, Gutter Marks, and Furrows 178
3.2 Other Erosional Bedforms Produced by Turbulent Flow: Channels and Rills 179
3.3 Erosional Bedforms Caused by Imprints of Objects: Bounce, Brush, Skip, Prod, Groove, Roll and Chevron Marks 180
3.4 Bedforms Produced by Objects Lying on the Seafloor: Obstacle Marks and Current Crescents 181
4 Addressing Key Issues in Shallow Coastal Landform Evolution 182
4.1 Shallow Coastal Landform Changes: Geomorphometric Measurements 183
4.2 Shallow Coastal Landforms and Sediments: A New Approach to Benthic Habitat Mapping 184
5 Conclusions 184
References 185
11 Continental Shelf Landforms 191
Abstract 191
1 Introduction 191
2 Brief History of Research on Continental Shelf Landforms 193
3 Processes 195
4 Continental Shelf Landforms 196
4.1 Consolidated Bottoms 196
4.2 Erosive Morphologies 197
4.3 Prograding Landforms 199
4.4 Bedforms 200
4.5 Gas-Related Features 204
4.6 Anthropogenic Features 205
5 Key Research Questions and Future Directions 206
Acknowledgements 207
References 207
12 Submarine Glacial Landforms 213
Abstract 213
1 Introduction 214
2 Landforms Produced in Different Glacial-Process Environments 216
2.1 Subglacial Landforms 216
2.1.1 Mega-Scale Glacial Lineations and Other Streamlined Subglacial Landforms 216
2.1.2 Hill-Hole Pairs 222
2.1.3 Crevasse-Fill Ridges 223
2.1.4 Subglacial Glacifluvial Landforms 223
2.2 Ice-Marginal Landforms 224
2.2.1 Moraine Ridges 224
2.2.2 Grounding-Zone Wedges 226
2.2.3 Ice-Proximal Fans 226
2.2.4 Lateral Moraines 227
2.2.5 Trough-Mouth Fans 227
2.3 Glacimarine Landforms 228
2.3.1 Iceberg Ploughmarks 228
2.3.2 Smooth Basin Fill from Meltwater Plumes 229
2.4 Marine Landforms 229
3 Glacial Landforms on the Norwegian Margin: A Case Study 230
3.1 Landforms in Cross-Shelf Troughs 230
3.2 Landforms on Inter-Trough Banks 232
3.3 Landsystem Models for Fast- and Slow-Flowing Ice 232
4 Future Research Objectives 234
Acknowledgements 234
References 234
13 Submarine Landslides 241
Abstract 241
1 Introduction 242
2 Geomorphic Expression of Submarine Landslides 243
3 Investigating Submarine Landslides 244
3.1 Geomorphometric Analyses 245
3.2 Landslide Population Statistics 246
3.3 Very High Resolution Imaging and Repeat Surveying 248
3.4 3D Seismic Geomorphology of Submarine Landslides 251
4 Major Challenges and Future Directions 251
5 Conclusions 253
References 253
14 Submarine Canyons and Gullies 257
Abstract 257
1 Introduction 258
1.1 Definitions and Nomenclature 258
1.2 The Origin of Submarine Canyons 259
2 Submarine Canyon Morphology and Evolution 261
2.1 The Physiography of Submarine Canyons 261
2.2 A Brief Comparison with Fluvial Systems 262
2.3 Global Distribution of Submarine Canyons 263
2.4 Geomorphic Processes in Submarine Canyons 267
2.4.1 Sea Level and Regional Tectonic Forcing 267
2.4.2 Sedimentary and Hydrodynamic Processes 268
2.4.3 The Human Imprint 269
2.4.4 Marine Geohazards 271
3 Towards an Integrated Approach to Submarine Canyon Research 272
Acknowledgments 273
References 273
15 Submarine Fans and Their Channels, Levees, and Lobes 279
Abstract 279
1 Introduction 280
2 Five Decades of Submarine Fan Research—Challenges and Progress 282
3 Processes 284
4 Morphology of Submarine Channels and Their Levees 287
5 Morphology of Submarine Lobes 295
6 Key Research Questions and Future Directions 297
Acknowledgements 299
References 299
16 Contourite Drifts and Associated Bedforms 306
Abstract 306
1 Introduction 307
1.1 Scope and Terminology 307
1.2 Brief History of Study 308
2 Contourite Drifts 309
2.1 Sheeted Drifts 310
2.2 Mounded-Elongate Drifts 313
2.3 Channel-Related Drifts 314
2.4 Patch Drifts 315
2.5 Confined Drifts 315
2.6 Infill Drifts 315
2.7 Fault-Controlled Drifts 316
2.8 Mixed Drift Systems 316
3 Contourite Erosional Elements 317
3.1 Depositional Hiatuses 317
3.2 Regional Erosive Surface 318
3.3 Linear Erosional Features 319
4 Seismic Characteristics 320
4.1 First-Order Seismic Element (i.e. Drift Scale) 321
4.2 Second-Order Seismic Element (i.e. Depositional Seismic Units) 324
4.3 Third-Order Seismic Element (i.e. Seismic Facies) 325
5 Bottom Current Bedforms 325
5.1 Longitudinal Bedforms 327
5.2 Transverse Bedforms 328
6 Future Research 330
References 332
17 Volcanic Islands and Seamounts 337
Abstract 337
1 Introduction 338
2 Submarine Geomorphology of Volcanic Islands and Seamounts 339
3 Volcanic and Erosive-Depositional Landforms 339
3.1 Volcanic Cones 340
3.2 Lava Flows and Lava-Fed Deltas 342
3.3 Caldera Collapses 343
3.4 Landforms Associated to Wave Erosion and Sea-Level Fluctuations 344
3.5 Landforms Related to Gravity-Driven Instability Processes 345
3.6 Landforms Related to Confined/Unconfined Density Gravity Flows 346
4 Gaps in Present-Day Knowledge and Perspectives for the Future 347
Acknowledgements 348
References 349
18 Mid-ocean Ridges 352
Abstract 352
1 Introduction 353
2 Regional Geomorphology 355
3 Faults 356
4 Landslides 359
5 Volcanic Geomorphologic Features 359
6 Hydrothermal Springs 362
7 Sediment Transport and Deposition 362
8 Remaining Issues and Developments 362
References 365
19 Cold Seep Systems 369
Abstract 369
1 Introduction 372
2 Methods to Detect Cold Seeps Systems 374
3 Geomorphological Indicators of Cold Seeps 376
3.1 Mud Volcanoes 376
3.2 Pockmarks 380
3.3 Carbonate-Related Structures 382
3.3.1 Methane-Derived Authigenic Carbonates (MDACs) 382
3.3.2 “Forest” of Carbonate Chimneys 382
4 Geohazards and Ecosystem Habitats 384
5 Gaps in Knowledge and Key Research Questions 384
Acknowledgements 385
References 385
20 Abyssal Hills and Abyssal Plains 390
Abstract 390
1 Abyssal Hills 391
1.1 Abyssal Hills Are Shaped by Extensional Tectonics 391
1.2 Influence of the Thermal Structure of the Lithosphere 395
1.3 Influence of Spreading Rate 396
1.4 Influence of Mantle Hot Spots and Cold Spots 398
1.5 Influence of Ridge Segmentation 398
2 The Abyssal Plains 401
3 Some Outstanding Questions 404
3.1 What Is the Width of the Plate Boundary Zone at Mid-Ocean Ridges? 404
3.2 Do Abyssal Hills Offer Long-Lived Pathways for Fluids Through the Oceanic Crust? 405
3.3 How Does Mass Wasting Affect Abyssal Hill Morphology? 405
3.4 Are the Abyssal Plains as Featureless as We Think? 405
Acknowledgements 406
References 406
21 Oceanic Trenches 410
Abstract 410
1 Introduction 411
1.1 Discovery of Oceanic Trenches 411
1.2 Outer Rise and Trench Outer Slope 412
1.3 Trench Depression 413
1.4 Trench Inner Slope 417
2 Results 418
2.1 Sediment Starved Trench Off Northern Chile 418
2.2 Partly Sediment Filled Trench Off Central Chile 419
2.3 Sediment Flooded Trench off Cascadia 421
3 Discussion 421
3.1 Impact of Lower Plate Morphology on Earthquake Rupture 422
3.2 Transport and Redistribution of Sediment in Oceanic Trenches 422
3.3 Outer Rise Seismicity 423
4 Conclusion 424
References 424
22 Cold-Water Carbonate Bioconstructions 426
Abstract 426
1 Introduction 427
2 Coralligenous Bioconstructions 429
2.1 Geomorphology of Coralligenous Bioconstructions 431
2.2 Coralligenous Distribution 435
3 Cold-Water Coral Reefs and Carbonate Mounds 435
3.1 Cold Water Corals and Physical Habitats 435
3.2 Cold Water Coral Reefs 438
3.3 Development of Cold Water Coral Reefs and Mounds 440
4 Biodiversity of Deep-Sea Bioconstructions: Environmental Issues, Management Strategies and Future Perspectives 444
References 446
Applied Submarine Geomorphology 457
23 Applied Geomorphology and Geohazard Assessment for Deepwater Development 458
Abstract 458
1 Introduction 459
2 Approach 459
3 Datasets 463
4 Morphology Mapping and Geomorphology Assessment 464
5 Geohazard Assessment 468
6 Implications for Development 472
7 Conclusions 476
Acknowledgements 476
References 477
24 Seabed Mining 479
Abstract 479
1 Introduction 479
1.1 Marine Mineral Deposits 480
1.2 General Exploration Methods for Resource and Environmental Impact Assessment 481
2 Resource Description 482
2.1 Sand and Gravel 482
2.2 Mn Nodules 482
2.3 Seafloor Massive Sulphides (SMS) 483
3 Exploration Methods 484
3.1 Sand and Gravel 484
3.2 Mn-Nodules 486
3.3 Seafloor Massive Sulphides 489
4 Exploitation Methods 492
4.1 Sand and Gravel 492
4.2 Mn Nodules 493
4.3 Seafloor Massive Sulphides 494
5 Monitoring Exploitation and Environmental Impact 496
5.1 Sand and Gravel 496
5.2 Mn Nodules 497
5.3 Seafloor Massive Sulphides 498
References 498
25 Fishing Activities 501
Abstract 501
1 Introduction 502
1.1 A Brief History 503
2 Results 506
2.1 Spatial Distribution and Frequency of Bottom Trawling Efforts 506
2.2 Bottom Trawling Affected Sediment Transport 507
2.3 Lithological Effects of Bottom Trawling 511
2.4 Geochemical Effects of Bottom Trawling to the Seabed Sediment 515
2.5 Geochemical Effects of Bottom Trawling to the Water Column 515
2.6 Effects of Bottom Trawling on Biota 516
2.7 Bottom Trawling-Induced Changes to Soft Sediment Seascapes 518
2.8 Bottom Trawling-Induced Changes to Reefs and Other Biogenic Seascapes 521
3 Conclusion and Outlook 522
3.1 Adding the Effects of Bottom Trawling to the Geological Framework 522
3.2 Outlook 523
References 524
26 National Programmes: Geomorphological Mapping at Multiple Scales for Multiple Purposes 533
Abstract 533
1 Introduction 534
2 Geomorphological Mapping—Approaches and Challenges 536
3 Seabed Geomorphological Classification 538
4 Case Studies 541
4.1 MAREANO, Norway—Automated Identification of Biogenic Reefs on the Norwegian Shelf 541
4.2 INFOMAR, Ireland—Reprocessing of Bathymetric Data for Geomorphological Mapping 544
4.3 MAREMAP, UK—Addressing Multiple End-Users at Multiple-scales 545
References 549
Conclusion 551
27 Conclusion 552
28 Erratum to: Submarine Geomorphology 554
Erratum to:& #6