Periglacial Geomorphology

COLIN K. BALLANTYNE, PhD DSC FRSE FRSGS FGS FBSG is Emeritus Professor in Physical Geography, University of St Andrews, St. Andrews, Fife, Scotland, UK.

• Preface xiAcknowledgement xiii1 Introduction 11.1 The Periglacial Concept: Definitions and Scope 11.2 The Periglacial Realm 51.3 The Development of Periglacial Geomorphology 51.4 Periglacial Geomorphology: The Quaternary Context 72 Periglacial Environments 112.1 Introduction 112.2 Periglacial Climates 112.3 Soils in Periglacial Environments 172.4 Vegetation Cover in Periglacial Environments 182.5 Synthesis 203 Ground Freezing and Thawing 233.1 Introduction 233.2 Ground Heating and Cooling 233.3 Soil Freezing 283.4 Ice Segregation in Freezing Soils 323.5 Thaw Consolidation 373.6 Synthesis 384 Permafrost 394.1 Introduction 394.2 Permafrost Thermal Regime 404.3 Classification of Permafrost 434.4 Detection, Mapping and Modelling of Permafrost 444.5 Permafrost Distribution 464.6 Permafrost–glacier Interactions 534.7 The Geomorphic Importance of Permafrost 545 Ground Ice and Cryostratigraphy 575.1 Introduction 575.2 Genetic Classification of Ground Ice 575.3 Description of Ground Ice 625.4 Ice Contacts 665.5 Cryostratigraphy 675.6 The Transition Zone 695.7 Massive Ground Ice 725.8 Yedoma 766 Thermal Contraction Cracking: Ice Wedges and Related Landforms 816.1 Introduction 816.2 Thermal Contraction Cracking and Polygon Evolution 816.3 Ice Veins and Ice Wedges 846.4 Ice]wedge Polygons 876.5 Sand Veins and Sand Wedges 896.6 Composite Veins and Composite Wedges 906.7 Sand]wedge Polygons 906.8 Frost Cracking of Seasonally Frozen Ground 916.9 Thaw Modification of Frost Wedges 916.10 Frost]Wedge Pseudomorphs and Frost Polygons in Areas of Past Permafrost 927 Pingos, Palsas and other Frost Mounds 977.1 Introduction 977.2 Characteristics of Pingos 977.3 Hydrostatic Pingos 997.4 Hydraulic Pingos 1017.5 Pingo Problems and Problem Pingos 1047.6 Segregation Ice Mounds: Palsas, Lithalsas and Related Landforms 1057.7 Palsas 1067.8 Peat Plateaus 1097.9 Lithalsas 1097.10 Permafrost Plateaus 1117.11 Other Permafrost Mounds 1117.12 Ephemeral Frost Mounds 1127.13 Relict Permafrost Mounds 1138 Thermokarst 1178.1 Introduction 1178.2 Thermokarst Lakes and Drained Lake Basins 1188.3 Thermokarst Pits, Bogs and Fens 1318.4 Retrogressive Thaw Slumps 1328.5 Small]scale Thermokarst Features: Beaded Streams, Sinkholes and Thermokarst Gullies 1368.6 Sediment Structures associated with Thermokarst 1388.7 Relict Thermokarst Phenomena 1399 Seasonally Frozen Ground Phenomena 1439.1 Introduction 1439.2 Upfreezing of Clasts 1439.3 Frost Heave of Bedrock 1459.4 Patterned Ground: The Embroidery on the Landscape 1459.5 Patterned Ground Processes 1479.6 Sorted Patterned Ground 1489.7 Nonsorted Patterned Ground 1559.8 Cryoturbations 1619.9 Pedogenic Effects of Freezing and Thawing 1649.10 Fragipans 1669.11 Synthesis 16710 Rock Weathering and Associated Landforms 16910.1 Introduction 16910.2 Physical Weathering Processes 16910.3 Chemical Weathering Processes 17710.4 Biotic Weathering Processes 18010.5 Weathering Processes in Periglacial Environments 18010.6 Cold]climate Karst 18110.7 Tors 18210.8 Blockfields and Related Periglacial Regolith Covers 18510.9 Brecciated Bedrocks 19211 Periglacial Mass Movement and Hillslope Evolution 19511.1 Introduction 19511.2 Solifluction Processes 19511.3 Solifluction Landforms 20411.4 Pleistocene Solifluction Landforms and Slope Deposits 21011.5 Active]layer Failures 21311.6 Permafrost Creep 21511.7 Nivation 21711.8 Cryoplanation 22011.9 Slope Form and Slope Evolution 22212 Talus Slopes and Related Landforms 22512.1 Introduction 22512.2 Rockfall Talus 22512.3 The Geomorphic Role of Snow Avalanches 23412.4 Debris]flow Activity 23712.5 Rock Glaciers 24012.6 Pronival (Protalus) Ramparts 24812.7 Synthesis 25013 Fluvial Processes and Landforms 25313.1 Introduction 25313.2 Periglacial Hydrology 25313.3 Slopewash 25913.4 Slushflows 26113.5 Sediment Transport in Periglacial Rivers 26113.6 Bank and Channel Erosion 26313.7 River Channels 26613.8 Alluvial Landforms in Periglacial Environments 26813.9 Valley Form 27013.10 Pleistocene Periglacial Rivers 27113.11 Synthesis 27314 Wind Action 27514.1 Introduction 27514.2 Aeolian Processes 27514.3 Wind Erosion in Present Periglacial Environments 27614.4 Aeolian Deposits in Present Periglacial Environments 27914.5 Quaternary Aeolian Deposits 28814.6 Synthesis 29715 Periglacial Coasts 29915.1 Introduction 29915.2 The Nature of Periglacial Coasts 29915.3 The Role of Ice in Shoreline Evolution 30115.4 Ice]rich Permafrost Coasts 30315.5 Thermokarst Coasts 30515.6 Barrier Coasts 30615.7 Salt Marshes and Tidal Flats 30815.8 Rock Coasts 30815.9 Raised and Inherited Shorelines 30915.10 Lake Shorelines 31015.11 Synthesis 31116 Past Periglacial Environments 31316.1 Introduction 31316.2 Palaeoenvironmental Reconstruction Based on Periglacial Features 31416.3 Past Periglacial Environments of the British Isles 32216.4 Pre]Late Devensian Periglacial Features in the British Isles 32316.5 The Dimlington Stade in the British Isles 32516.6 The Younger Dryas (Loch Lomond) Stade in the British Isles 32916.7 Past Periglacial Environments of the British Isles: Commentary 33216.8 Late Weichselian Periglacial Environments in Continental Europe 33216.9 Late Wisconsinan Periglacial Environments in North America 34116.10 Permafrost Extent in the Northern Hemisphere During the Last Glacial Stage 34416.11 Concluding Comments 34617 Climate Change and Periglacial Environments 34917.1 Introduction 34917.2 Permafrost Degradation 35217.3 Geomorphological Implications of Climate Change in the Circumpolar North 35617.4 Geomorphological Implications of Climate Change in High Mountain Environments 36317.5 Climate Change, Permafrost Degradation and Greenhouse Gas Emissions 36917.6 Conclusion 371Appendix: Text Abbreviations, Units and Symbols Employed in Equations 373References 375Index 441