Description
Book SynopsisTable of ContentsPreface xi
Acknowledgement xiii
1 Introduction 1
1.1 The Periglacial Concept: Definitions and Scope 1
1.2 The Periglacial Realm 5
1.3 The Development of Periglacial Geomorphology 5
1.4 Periglacial Geomorphology: The Quaternary Context 7
2 Periglacial Environments 11
2.1 Introduction 11
2.2 Periglacial Climates 11
2.3 Soils in Periglacial Environments 17
2.4 Vegetation Cover in Periglacial Environments 18
2.5 Synthesis 20
3 Ground Freezing and Thawing 23
3.1 Introduction 23
3.2 Ground Heating and Cooling 23
3.3 Soil Freezing 28
3.4 Ice Segregation in Freezing Soils 32
3.5 Thaw Consolidation 37
3.6 Synthesis 38
4 Permafrost 39
4.1 Introduction 39
4.2 Permafrost Thermal Regime 40
4.3 Classification of Permafrost 43
4.4 Detection, Mapping and Modelling of Permafrost 44
4.5 Permafrost Distribution 46
4.6 Permafrost–glacier Interactions 53
4.7 The Geomorphic Importance of Permafrost 54
5 Ground Ice and Cryostratigraphy 57
5.1 Introduction 57
5.2 Genetic Classification of Ground Ice 57
5.3 Description of Ground Ice 62
5.4 Ice Contacts 66
5.5 Cryostratigraphy 67
5.6 The Transition Zone 69
5.7 Massive Ground Ice 72
5.8 Yedoma 76
6 Thermal Contraction Cracking: Ice Wedges and Related Landforms 81
6.1 Introduction 81
6.2 Thermal Contraction Cracking and Polygon Evolution 81
6.3 Ice Veins and Ice Wedges 84
6.4 Ice]wedge Polygons 87
6.5 Sand Veins and Sand Wedges 89
6.6 Composite Veins and Composite Wedges 90
6.7 Sand]wedge Polygons 90
6.8 Frost Cracking of Seasonally Frozen Ground 91
6.9 Thaw Modification of Frost Wedges 91
6.10 Frost]Wedge Pseudomorphs and Frost Polygons in Areas of Past Permafrost 92
7 Pingos, Palsas and other Frost Mounds 97
7.1 Introduction 97
7.2 Characteristics of Pingos 97
7.3 Hydrostatic Pingos 99
7.4 Hydraulic Pingos 101
7.5 Pingo Problems and Problem Pingos 104
7.6 Segregation Ice Mounds: Palsas, Lithalsas and Related Landforms 105
7.7 Palsas 106
7.8 Peat Plateaus 109
7.9 Lithalsas 109
7.10 Permafrost Plateaus 111
7.11 Other Permafrost Mounds 111
7.12 Ephemeral Frost Mounds 112
7.13 Relict Permafrost Mounds 113
8 Thermokarst 117
8.1 Introduction 117
8.2 Thermokarst Lakes and Drained Lake Basins 118
8.3 Thermokarst Pits, Bogs and Fens 131
8.4 Retrogressive Thaw Slumps 132
8.5 Small]scale Thermokarst Features: Beaded Streams, Sinkholes and Thermokarst Gullies 136
8.6 Sediment Structures associated with Thermokarst 138
8.7 Relict Thermokarst Phenomena 139
9 Seasonally Frozen Ground Phenomena 143
9.1 Introduction 143
9.2 Upfreezing of Clasts 143
9.3 Frost Heave of Bedrock 145
9.4 Patterned Ground: The Embroidery on the Landscape 145
9.5 Patterned Ground Processes 147
9.6 Sorted Patterned Ground 148
9.7 Nonsorted Patterned Ground 155
9.8 Cryoturbations 161
9.9 Pedogenic Effects of Freezing and Thawing 164
9.10 Fragipans 166
9.11 Synthesis 167
10 Rock Weathering and Associated Landforms 169
10.1 Introduction 169
10.2 Physical Weathering Processes 169
10.3 Chemical Weathering Processes 177
10.4 Biotic Weathering Processes 180
10.5 Weathering Processes in Periglacial Environments 180
10.6 Cold]climate Karst 181
10.7 Tors 182
10.8 Blockfields and Related Periglacial Regolith Covers 185
10.9 Brecciated Bedrocks 192
11 Periglacial Mass Movement and Hillslope Evolution 195
11.1 Introduction 195
11.2 Solifluction Processes 195
11.3 Solifluction Landforms 204
11.4 Pleistocene Solifluction Landforms and Slope Deposits 210
11.5 Active]layer Failures 213
11.6 Permafrost Creep 215
11.7 Nivation 217
11.8 Cryoplanation 220
11.9 Slope Form and Slope Evolution 222
12 Talus Slopes and Related Landforms 225
12.1 Introduction 225
12.2 Rockfall Talus 225
12.3 The Geomorphic Role of Snow Avalanches 234
12.4 Debris]flow Activity 237
12.5 Rock Glaciers 240
12.6 Pronival (Protalus) Ramparts 248
12.7 Synthesis 250
13 Fluvial Processes and Landforms 253
13.1 Introduction 253
13.2 Periglacial Hydrology 253
13.3 Slopewash 259
13.4 Slushflows 261
13.5 Sediment Transport in Periglacial Rivers 261
13.6 Bank and Channel Erosion 263
13.7 River Channels 266
13.8 Alluvial Landforms in Periglacial Environments 268
13.9 Valley Form 270
13.10 Pleistocene Periglacial Rivers 271
13.11 Synthesis 273
14 Wind Action 275
14.1 Introduction 275
14.2 Aeolian Processes 275
14.3 Wind Erosion in Present Periglacial Environments 276
14.4 Aeolian Deposits in Present Periglacial Environments 279
14.5 Quaternary Aeolian Deposits 288
14.6 Synthesis 297
15 Periglacial Coasts 299
15.1 Introduction 299
15.2 The Nature of Periglacial Coasts 299
15.3 The Role of Ice in Shoreline Evolution 301
15.4 Ice]rich Permafrost Coasts 303
15.5 Thermokarst Coasts 305
15.6 Barrier Coasts 306
15.7 Salt Marshes and Tidal Flats 308
15.8 Rock Coasts 308
15.9 Raised and Inherited Shorelines 309
15.10 Lake Shorelines 310
15.11 Synthesis 311
16 Past Periglacial Environments 313
16.1 Introduction 313
16.2 Palaeoenvironmental Reconstruction Based on Periglacial Features 314
16.3 Past Periglacial Environments of the British Isles 322
16.4 Pre]Late Devensian Periglacial Features in the British Isles 323
16.5 The Dimlington Stade in the British Isles 325
16.6 The Younger Dryas (Loch Lomond) Stade in the British Isles 329
16.7 Past Periglacial Environments of the British Isles: Commentary 332
16.8 Late Weichselian Periglacial Environments in Continental Europe 332
16.9 Late Wisconsinan Periglacial Environments in North America 341
16.10 Permafrost Extent in the Northern Hemisphere During the Last Glacial Stage 344
16.11 Concluding Comments 346
17 Climate Change and Periglacial Environments 349
17.1 Introduction 349
17.2 Permafrost Degradation 352
17.3 Geomorphological Implications of Climate Change in the Circumpolar North 356
17.4 Geomorphological Implications of Climate Change in High Mountain Environments 363
17.5 Climate Change, Permafrost Degradation and Greenhouse Gas Emissions 369
17.6 Conclusion 371
Appendix: Text Abbreviations, Units and Symbols Employed in Equations 373
References 375
Index 441
