Deep Marine Systems

Preface xi
About the companion website xiii
Part 1 Process and product 1
1 Physical and biological processes 3
1.1 Introduction 4
1.2 Shelf-edge processes 5
1.2.1 High-level escape of mud from the shelf 5
1.2.2 Currents in submarine canyons 7
1.2.3 Internal waves 9
1.2.4 Sediment slides and mass transport complexes (MTCs) 10
1.3 Deep, thermohaline, clear-water currents 12
1.4 Density currents and sediment gravity flows 16
1.4.1 Classification 17
1.4.2 Transformations between flow types 21
1.5 Turbidity currents and turbidites 23
1.5.1 Definition and equations of flow 23
1.5.2 Natural variations and triggering processes 27
1.5.3 Supercritical flow of turbidity currents 32
1.5.4 Autosuspension in turbidity currents 33
1.5.5 Effects of obstacles in the flow path 33
1.5.6 Turbidites 34
1.5.7 Cross-stratification in turbidites 36
1.5.8 Antidunes in turbidites 37
1.5.9 Turbidites from low-concentration flows 38
1.5.10 Downcurrent grain size-bed thickness trends in turbidites 40
1.5.11 Time scales for turbidite deposition 40
1.6 Concentrated density flows and their deposits 42
1.6.1 Deposits from concentrated density flows 42
1.6.2 Large mud clasts in concentrated density-flow deposits 44
1.7 Inflated sandflows and their deposits 45
1.7.1 Deposits of inflated sandflows 45
1.8 Cohesive flows and their deposits 46
1.8.1 Definitions and equations of flow 46
1.8.2 Turbulence of cohesive flows 48
1.8.3 Competence of cohesive flows 49
1.8.4 Deposits of cohesive flows, including debrites 49
1.8.5 Submarine versus subaerial cohesive flows 52
1.9 Accumulation of biogenic skeletons and organic matter 52
1.9.1 Environmental information from biogenic skeletons 55
2 Sediments (facies) 59
2.1 Introduction 60
2.2 Facies classifications 60
2.2.1 Seismic facies 62
2.2.2 The Pickering et al. classification scheme 62
2.3 Facies Class A: Gravels, muddy gravels, gravelly muds, pebbly sands, >=5% gravel grade 65
2.3.1 Facies Group A1: Disorganised gravels, muddy gravels, gravelly muds and pebbly sands 66
2.3.2 Facies Group A2: Organised gravels and pebbly sands 69
2.4 Facies Class B: Sands, >80% sand grade,
2.4.1 Facies Group B1: Disorganised sands 76
2.4.2 Facies Group B2: Organised sands 77
2.5 Facies Class C: Sand-mud couplets and muddy sands, 20-80% sand grade,
2.5.1 Facies Group C1: Disorganised muddy sands 79
2.5.2 Facies Group C2: Organised sand-mud couplets 82
2.6 Facies Class D: Silts, silty muds, and silt-mud couplets, >80% mud, >=40% silt, 0-20% sand 85
2.6.1 Facies Group D1: Disorganised silts and silty muds 85
2.6.2 Facies Group D2: Organised silts and muddy silts 87
2.7 Facies Class E: >=95% mud grade,
2.7.1 Facies Group E1: Disorganised muds and clays 90
2.7.2 Facies Group E2: Organised muds 94
2.8 Facies Class F: Chaotic deposits 98
2.8.1 Facies Group F1: Exotic clasts 98
2.8.2 Facies Group F2: Contorted/disturbed strata 99
2.9 Facies Class G: Biogenic oozes (>75% biogenics), muddy oozes (50-75% biogenics), biogenic muds (25-50% biogenics) and chemogenic sediments,
2.9.1 Facies Group G1: Biogenic oozes and muddy oozes 102
2.9.2 Facies Group G2: Biogenic mud 104
2.10 Injectites (clastic dykes and sills) (Figs 2.46-2.50) 105
2.11 Facies associations 111
3 Deep-water ichnology 112
3.1 Introduction 112
3.2 General principles of ichnology 113
3.2.1 Preservational classification of trace fossils 113
3.2.2 Ethological classification of trace fossils 114
3.2.3 Taxonomic classification of common deep-water trace fossils 115
3.3 Colonisation of SGF deposits: Opportunistic and equilibrium ecology 122
3.4 Ichnofacies 125
3.5 Ichnofabrics 127
3.6 Trace fossils in core 128
3.7 Case study I: Trace fossils as diagnostic indicators of deep-marine environments, Middle Eocene Ainsa-Jaca basins, Spanish Pyrenees 129
3.7.1 Introduction 129
3.7.2 Study area: Ainsa-Jaca basins 129
3.7.3 Trace-fossil distributions 129
3.7.4 Interpretation 129
3.8 Case study II: Subsurface ichnological characterisation of the Middle Eocene Ainsa deep-marine system, Spanish Pyrenees 130
3.8.1 Introduction 130
3.8.2 Trace-fossil distributions and ichnofabrics in the Ainsa System, Ainsa Basin, Spanish Pyrenees 130
3.8.3 Interpretation 132
3.9 Summary of ichnology studies in deep-water systems 134
3.10 Concluding remarks 134
4 Time-space integration 136
4.1 Introduction 136
4.2 Submarine fan growth phases and sequence stratigraphy 144
4.2.1 Early models for fan development and relative base-level change 144
4.2.2 California Borderland submarine fans and base-level change 149
4.2.3 Recent studies of ancient submarine fans and inferred base-level changes 151
4.3 Tectono-thermal/glacio-eustatic controls at evolving passive continental margins 153
4.4 Eustatic sea-level changes at active plate margins 154
4.5 Changing relative base level and sediment delivery processes 160
4.6 Autocyclic processes 164
4.6.1 Autocyclicity in submarine channels 164
4.6.2 Fill-and-spill model for slope basins 167
4.6.3 Autocyclicity in fan deltas 170
4.7 Palaeo-seismicity and the stratigraphic record 171
4.8 Deconvolving tectonic and climatic controls on depositional sequences in tectonically active basins: Case study from the Eocene, Spanish Pyrenees 171
4.9 Problems in determining controls on sediment delivery 183
4.10 Carbonate versus siliciclastic systems 191
4.11 Computer simulations of deep-water stratigraphy 193
4.12 Laboratory simulations of deep-water stratigraphy 193
4.13 Supercritical versus subcritical fans 194
4.14 Hierarchical classification of depositional units 195
4.15 Concluding comments 196
5 Statistical properties of sediment gravity flow (SGF) deposits 200
5.1 Introduction 200
5.2 Cloridorme Formation, Middle Ordovician, Québec 205
5.3 Vertical trends 218
5.3.1 Tests for randomness 223
5.3.2 Correlation tests to identify asymmetric trends 224
5.3.3 Realisation that asymmetric trends can be formed, at low probability, by random processes 227
5.3.4 Asymmetric trends in the grain size of SGF deposits 230
Part 2 Systems 237
6 Sediment drifts and abyssal sediment waves 239
6.1 Introduction 239
6.2 Distribution and character of contourites and sediment drifts, North Atlantic Ocean 241
6.2.1 Broad sheeted drifts 243
6.2.2 Elongate drifts 245
6.2.3 Sediment waves 245
6.2.4 Thin contourite sheets 249
6.2.5 Other abyssal current-generated structures 249
6.3 Facies of muddy and sandy contourites 251
6.4 Seismic facies of contourites 255
6.5 The debate concerning bottom-current reworking of sandy fan sediments 255
6.6 Ancient contourites 257
6.6.1 Talme Yafe Formation 258
6.7 Facies model for sediment drifts 260
7 Submarine fans and related depositional systems: modern 262
7.1 Introduction 262
7.2 Major controls on submarine fans 266
7.2.1 Sediment type 266
7.2.2 Tectonic setting and activity 266
7.2.3 Sea-level fluctuations 267
7.3 Submarine canyons 274
7.3.1 Shifting locus of coarse-grained clastic input 277
7.4 Architectural elements of submarine-fan systems 277
7.4.1 Channels and channel-levée systems 280
7.4.2 Waveforms (sediment waves) 290
7.4.3 Lobes 294
7.4.4 Sheets 298
7.4.5 Scours and megaflutes 299
7.4.6 Mass-transport complexes 302
7.5 The distribution of architectural elements in modern submarine fans 303
7.6 Modern non-fan dispersal systems 303
7.7 Concluding remarks 307
8 Submarine fans and related depositional systems: ancient 309
8.1 Introduction 309
8.2 Ancient submarine canyons 311
8.3 Ancient submarine channels 313
8.3.1 Channel scale, architecture and stacking patterns 313
8.3.2 Channel stacking 329
8.3.3 Case study: Milliners Arm Formation, NewWorld Island, Newfoundland 333
8.3.4 Levées 341
8.3.5 Lateral accretion deposits (LAPs) 347
8.3.6 Post-depositional modification of channel fills 354
8.4 Comparing modern and ancient channels 355
8.5 Ancient lobe, lobe-fringe, fan-fringe and distal basin-floor deposits 357
8.6 Seafloor topography and onlaps 369
8.7 Scours 377
8.8 Basin-floor sheet-like systems 382
8.9 Prodeltaic clastic ramps 387
8.10 Concluding remarks 393
Part 3 Plate tectonics and sedimentation 403
9 Evolving and mature extensional systems 405
9.1 Introduction 406
9.2 Models for lithospheric extension 408
9.3 Subsidence and deep-water facies of rifts and young passive margins 410
9.4 The post-breakup architecture of passive margins 413
9.4.1 Passive margins outboard of major deltas 415
9.4.2 Passive margins underlain by mobile salt 415
9.4.3 Slope apron of the northwest African margin 416
9.4.4 Passive margins swept by bottom currents 417
9.4.5 Glaciated passive margins 421
9.4.6 Carbonate platforms and ramps 425
9.5 Failed rift systems 428
9.6 Fragments of ancient passive margins 429
9.7 Concluding remarks 430
10 Subduction margins 433
10.1 Introduction 433
10.2 Modern subduction factories 435
10.2.1 Forearcs 435
10.2.2 Trench sedimentation 437
10.2.3 Accretionary prisms 443
10.2.4 Role of seamounts in subduction factory 449
10.2.5 Very oblique convergence and strike-slip in subduction factory 453
10.2.6 Preservation and recognition of trench stratigraphy 459
10.2.7 Forearc basins/slope basins 459
10.2.8 Fluid flow and plumbing in forearc settings 467
10.3 Arc-arc collision zones 474
10.4 Forearc summary model 482
10.5 Marginal/backarc basins 483
10.6 Ancient convergent-margin systems 488
10.7 Forearc/backarc cycles 493
10.8 Concluding remarks 493
11 Foreland basins 497
11.1 Introduction 498
11.2 Modern foreland basins 499
11.2.1 Neogene-Quaternary Taiwan 499
11.2.2 Neogene Quaternary Southern Banda Arc 502
11.3 Ancient deep-marine foreland basins 506
11.3.1 Permo-Triassic Karoo foreland basin, South Africa 507
11.3.2 Oligocene-Miocene foreland basin, Italian Apennines 509
11.3.3 Lower Palaeozoic foreland basin, Quebec Appalachians 513
11.3.4 South Pyrenean foreland basin and thrust-top/piggyback basins 515
11.4 Concluding remarks 523
12 Strike-slip continental margin basins 528
12.1 Introduction 528
12.2 Kinematic models for strike-slip basins 529
12.3 Suspect terranes 529
12.4 Depositional models for strike-slip basins 532
12.5 Modern strike-slip mobile zones 537
12.5.1 Californian continental margin 541
12.5.2 Gulf of California transtensional ocean basin 555
12.6 Ancient deep-marine oblique-slip mobile zones 557
12.6.1 Mesozoic Pyrenees 560
12.6.2 Lower Palaeozoic north central Newfoundland and Britain 562
12.7 Concluding remarks 566
References 573
Index 647