Preface ........................................................ xi
Acknowledgements ............................................... xv
1 Introduction to the study of surface processes ............... 2
The global context ........................................... 4
Overview of geomorphology .................................... 5
Guiding principles ........................................... 6
Conservation .............................................. 6
Transport rules ........................................... 7
Event size and frequency .................................. 7
Establishing timing: rates of processes and ages of
landscapes ................................................... 8
What drives geomorphic processes? ............................ 8
The surface temperature of the Earth ......................... 9
The climate context .......................................... 9
Summary ..................................................... 13
Problems .................................................... 14
Further reading ............................................. 14
2 Whole Earth morphology ...................................... 16
Why an oblate spheroid? ..................................... 18
Topographic statistics: Earth's hypsometry .................. 21
Summary ..................................................... 24
Problems .................................................... 24
Further reading ............................................. 25
3 Large-scale topography ...................................... 26
Ocean basins: the marriage of conduction and isostasy ....... 28
Plate tectonics overview .................................... 36
The motion of plates ..................................... 36
Plate speeds ............................................. 37
Large-scale mountain ranges: orogens ........................ 38
Effects of thickening the crust .......................... 39
Effects of erosion on the isostatic balance .............. 41
Mantle response times: geomorphology as a probe of mantle
rheology .................................................... 43
Ice sheet and ocean loading and the response of the
Earth surface to it ...................................... 44
Mantle flow and its influence on topography ................. 49
Dynamic topography ....................................... 49
Topographic oozing of the Tibetan Plateau margin ......... 50
Gooshing of mantle across the continental edge ........... 52
Summary ..................................................... 55
Problems .................................................... 57
Further reading ............................................. 59
4 Tectonic geomorphology ...................................... 60
Deformation associated with individual faults ............... 62
Fault scaling and fault interaction ...................... 65
Coulomb stress changes ................................... 67
Determination of offsets from modern earthquakes ............ 69
Paleoseismology ............................................. 71
Strike-slip faults ....................................... 71
Normal faults ............................................ 72
Megathrust faults ........................................ 75
Long-term deformation: cumulative displacement deduced
from offsets of geomorphic markers .......................... 78
Marine platforms ......................................... 79
River profiles ........................................... 83
The special case of corals ............................... 84
Flexure ..................................................... 86
Generation of mountain ranges by repeated earthquakes ....... 91
Summary ..................................................... 93
Problems .................................................... 94
Further reading ............................................. 95
5 Atmospheric processes and geomorphology ..................... 96
The Sun ..................................................... 98
Climate and weather processes ............................... 99
Why is Earth the "water planet"? ........................... 100
The spatial pattern of radiation ........................... 104
Vertical structure of the atmosphere ....................... 107
Wind and atmospheric circulation ........................... 108
Hadley cells ............................................ 108
Monsoons ................................................ 110
Sea breezes ............................................. 112
Katabatic winds ......................................... 112
Orographic effects ...................................... 113
Summary .................................................... 117
Problems ................................................... 118
Further reading ............................................ 119
6 Dating methods, and establishing timing in the landscape ... 120
Relative dating methods .................................... 122
Absolute dating methods .................................... 122
Paleomagnetic dating .................................... 123
Optically stimulated luminescence (OSL) ................. 123
Amino acid racemization ................................. 124
Oxygen isotopes and the marine isotope stages ........... 126
Radiometric dating methods .............................. 128
Cosmogenic radionuclides ................................ 131
Shallow geothermometry: establishing long-term rates of
exhumation ................................................. 146
Fission tracks .......................................... 147
Ar/Ar thermochronometry ................................. 148
(U-Th)IHe method ........................................... 151
Summary .................................................... 157
Problems ................................................... 157
Further reading ............................................ 159
7 Weathering ................................................. 160
Weathering as part of erosion .............................. 162
The weathered profile ...................................... 162
The Critical Zone .......................................... 164
Denudation ................................................. 165
Mass loss ............................................... 165
Processes that fracture rock ............................... 166
Thermal stress and strain ............................... 168
Frost cracking .......................................... 173
Other fracturing processes .............................. 176
The deeper history of fractures ......................... 177
Fractures and rock strength ............................. 181
Chemical alteration of rock ................................ 183
Chemical equilibrium .................................... 183
Solubility and saturation ............................... 185
Rivers, continental crust, and common chemical
weathering reactions .................................... 186
Chemical kinetics ....................................... 191
Long-term carbon cycle ..................................... 200
Effects of chemical alteration of rock ..................... 202
Assessing mass losses (or gains) in regolith ............ 202
Chemical alteration of rock strength .................... 205
The conversion of bedrock to mobile regolith ............... 207
Mobile-regolith production junctions .................... 207
Summary .................................................... 208
Problems ................................................... 210
Further reading ............................................ 211
8 Glaciers and glacial geology ............................... 212
Glaciology: what are glaciers and how do they work? ........ 214
Types of glaciers: a bestiary of ice ....................... 215
Mass balance ............................................... 216
Ice deformation ............................................ 219
The rheology ............................................ 221
Ice wrinkles 1: Glen's flow law ......................... 223
Ice wrinkles 2: sliding/regelation ...................... 225
Basal motion by till deformation ........................ 232
Applications of glaciology ................................. 232
Glacier simulations ..................................... 232
Paleo-climate estimates from glacial valleys ............ 233
Ice sheet profiles ...................................... 234
Surging glaciers and the stability of ice sheets ........ 236
Tidewater glaciers ...................................... 237
The great ice sheets: Antarctica and Greenland ............. 241
Glacial geology: erosional forms and processes ............. 245
Erosional processes ........................................ 245
Abrasion ................................................ 246
Quarrying ............................................... 248
Large-scale erosional forms ................................ 251
The U-shaped valley ..................................... 251
Cirques, steps, and overdeepenings: the long valley
profile ................................................. 252
Fjords .................................................. 255
Depositional forms ......................................... 257
Moraines ................................................ 257
Eskers .................................................. 260
Erosion rates .............................................. 263
Summary .................................................... 265
Problems ................................................... 267
Further reading ............................................ 268
9 Periglacial processes and forms ............................ 270
Definition and distribution of permafrost .................. 272
Thermal structure .......................................... 272
Base of the permafrost .................................. 273
Active layer depth ...................................... 275
Latent heat ............................................. 277
Departures from the steady-state geotherm ............... 278
Geomorphology of periglacial regions ....................... 280
Segregation ice and frost heave ......................... 280
Upfreezing of stones .................................... 283
Patterned ground ........................................ 285
Ice wedge polygons ...................................... 286
Solifluction lobes ...................................... 290
Pingos .................................................. 290
Thaw lakes .............................................. 293
The present rapidly changing Arctic ........................ 296
Thermokarst ................................................ 296
Coastal erosion ............................................ 298
Permafrost and carbon ...................................... 299
Summary .................................................... 300
Problems ................................................... 301
Further reading ............................................ 303
10 Hillslopes ................................................. 304
Convexity of hilltops ...................................... 307
Mass balance ............................................... 308
Diffusive processes ........................................ 309
Hillslope processes ........................................ 313
Rainsplash .............................................. 313
Creep ................................................... 320
Solifluction: frost creep and gelifluction .............. 320
Biogenic process examples ............................... 325
Pacing hillslopes .......................................... 328
Landslides ................................................. 330
The force balance at failure ............................ 331
A primer on the behavior of saturated granular
materials ............................................... 334
What oversteepens the slopes? ........................... 336
The aftermath ........................................... 337
Debris flows ............................................... 340
Hillslope models ........................................... 344
Summary .................................................... 345
Problems ................................................... 346
Further reading ............................................ 347
11 Water in the landscape ..................................... 348
Drainage basins ............................................ 350
Water balance .............................................. 352
Soil moisture and its distribution with depth .............. 353
Infiltration ............................................... 355
Groundwater ................................................ 358
The Dupuit case ......................................... 360
Groundwater rules of thumb .............................. 363
Runoff mechanisms .......................................... 363
Infiltration capacity ................................... 365
Roles of vegetation ..................................... 365
Evapotranspiration ...................................... 365
Water storage in the soil ............................... 366
Overland flow generation ................................ 366
Overland How of water and its geomorphie consequences ...... 367
The problem of drainage density ............................ 370
Sapping and amphitheater-headed canyons ................. 373
Summary of channel head issues .......................... 374
Hydrology of a headwater catchment: the Coos Bay
experiment ................................................. 374
Summary .................................................... 376
Problems ................................................... 377
Further reading ............................................ 378
12 Rivers ..................................................... 380
Theory and measurement of turbulent flows in open
channels ................................................... 382
The vertically averaged mean velocity ................... 388
Other equations for the mean velocity ................... 389
Measurement of channel velocity and discharge ........... 391
Summary of theory and measurement of channel flow ....... 394
Hydraulic geometry ......................................... 395
Floods and floodplain sedimentation ........................ 396
The flood plain ......................................... 399
Channel plan views ......................................... 399
The braided ease ........................................ 400
The meandering ease ..................................... 401
Channel profiles ........................................... 405
Character of the bed .................................... 407
River slopes ............................................ 408
The influence of base level ............................. 409
The Amazon ................................................. 411
Summary .................................................... 414
Appendix: The Navier-Stokes equation and the origin of
the Reynolds and Froude numbers ............................ 414
The left-hand side ...................................... 415
The right-hand side ..................................... 415
Non-dimensionalization of the Navier-Stokes equation .... 418
Problems ................................................... 419
Further reading ............................................ 421
13 Bedrock channels ........................................... 422
Measurement techniques ..................................... 424
Straths ................................................. 425
Lava flows .............................................. 425
Caves ................................................... 425
Cosmogenic radionuclides on the channel floor ........... 426
Short-term monitoring ................................... 426
Erosion processes .......................................... 428
The stream power approach ............................... 428
Abrasion ................................................ 429
Quarrying ............................................... 431
Hydraulic wedging ....................................... 433
Dissolution ............................................. 433
Knickpoint migration .................................... 434
Summary of processes .................................... 435
Stream profiles in bedrock channels ........................ 435
The channel width problem .................................. 445
Empirical constraints ................................... 446
Theory .................................................. 446
Summary .................................................... 449
Appendix: Future work and research needs ................... 449
Problems ................................................... 450
Further reading ............................................ 451
14 Sediment transport mechanics ............................... 452
The pieces of the problem .................................. 454
Grain entrainment .......................................... 455
Recent progress in the fluvial realm .................... 459
Modes of transport ......................................... 461
The saltation trajectory ................................ 462
The granular splash ..................................... 463
Mass flux: transport "laws" ............................. 464
Suspended sediment transport ............................... 468
The suspension trajectory ............................... 468
The continuum approach .................................. 469
Summary .................................................... 473
Problems ................................................... 474
Further reading ............................................ 475
15 Eolian forms and deposits .................................. 476
Bedforms ................................................... 478
Classification of dune types ............................ 481
Models of dunes and their stratigraphy .................. 484
Eolian ripples .......................................... 486
Summary of bedforms ..................................... 489
Loess ...................................................... 489
Erosion by windblown particles ............................. 493
Windblown snow ............................................. 497
Eolian evidence on Mars .................................... 498
Summary .................................................... 499
Problems ................................................... 500
Further reading ............................................ 501
16 Coastal geomorphology ...................................... 502
The relative movement of land and sea ...................... 504
The Pleistocene record .................................. 504
Sect level change in the Holocene ....................... 505
The last century of sea level change and its causes ..... 506
Rock uplift ............................................. 507
Waves ...................................................... 508
Origin of waves ......................................... 508
Transformation of waves ................................. 510
Hurricane storm surge ................................... 511
Physics of sand movement in the littoral system ............ 512
Sandy coasts ............................................... 513
Capes and spits ......................................... 513
Beach cusps ............................................. 514
Deltas .................................................. 515
Rocky coasts ............................................... 520
Coastal littoral sand budget ............................ 521
Pocket beaches and headlands ............................ 523
Icy coasts ................................................. 524
The continental shelf ...................................... 526
Summary .................................................... 528
Problems ................................................... 530
Further reading ............................................ 531
17 The geomorphology of big floods ............................ 532
Why should we study large floods? .......................... 534
A historical backdrop ...................................... 534
A recipe for truly big Hoods: a bunch of water, a breach
of the dam ................................................. 535
Paleoflood analysis ........................................ 537
Slackwater and separation eddy deposits ................. 538
Estimates of flow competence ............................ 538
Paleodischarge estimates ................................ 538
The Bonneville flood ....................................... 538
Glacial Hoods: Jökulhlaups ................................. 540
The Lake Missoula floods and the channeled scablands ....... 541
Lakes Agassi/ and Ojibway .................................. 546
The English Channel reinterpreted .......................... 549
Noah's flood ............................................... 549
Floods from the failure of landslide dams .................. 553
Summary .................................................... 554
Problems ................................................... 554
Further reading ............................................ 555
18 Whole landscapes ........................................ 556
The Santa Cruz landscape: introduction ..................... 558
Rock uplift: advection around a fault bend ................. 560
Evolution of the terraces .................................. 562
Stream channels ............................................ 563
Terrace ages ............................................... 565
Evolution of soils on the terraces ......................... 567
Implications of the weathering of soils for the
hydrology .................................................. 568
Littoral system ............................................ 568
Seacliff evolution ......................................... 573
Long-term evolution of the coastal plan view ............... 579
Summary .................................................... 580
Problems ................................................... 580
Further reading ............................................ 581
Appendix A: Physics ........................................... 582
Primary units .............................................. 582
Key definitions ............................................ 582
Heat transport mechanisms .................................. 583
Rheologies ................................................. 583
Important dimensionless numbers ............................ 583
Important natural constants ................................ 583
Physical properties ........................................ 583
Appendix B: Mathematics .................................... 584
Numbers worth memorizing ................................... 584
Important functions ........................................ 584
Basic rules of thumb for manipulation of expressions ....... 591
Trigonometry ............................................... 591
Geometry ................................................... 592
Volume, area, and circumference ......................... 592
Algebra .................................................... 592
Calculus ................................................... 592
Derivatives ............................................. 592
Integrals ............................................... 594
Mean value theorem ...................................... 594
Taylor series expansion ................................. 594
Ordinary differential equations (ODEs) ..................... 595
Partial differential equations (PDEs) ...................... 596
Statistics ................................................. 596
Probability density functions (PDFs) ....................... 597
Goodness of fit ............................................ 599
References .................................................... 600
Index ......................................................... 635
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