The Dictionary of Physical Geography, Third Edition

Contents Preface to the Third Edition Preface to the First Edition Preface to the Second Edition Introduction

vi VB Vlll IX

Acknowledgements

X

List of Contributors

xi

THE DICTIONARY OF PHYSICAL GEOGRAPHY Index

540

v

Preface to the Third Edition This edition of this dictionary represents substantial evolution from the second edition. Following consultation with the international advisory panel, whose composition reflects many key areas of physical geography including biogeography, climatology, environmental change and key areas of geomorphology, 200 entries from the second edition have been removed, and replaced with 450 new entries. These were chosen from an original list of possible new entries over twice this length, with the final selection representing changes within the discipline, an increased international flavour, and the need to maintain the final volume at a certain length. The total list of contributors is increased by 34, with new experts drawn in to add their knowledge to the volume. Managing a volume of this size is a complex task, the size of which I did not quite realize when approached by John Davey, formerly of Blackwell Publishers, and Andrew Goudie. Completion of the task has been made much simpler due to the help of the advisory panel, the goodwill of contributors, and especially to the assistance of Jill Landeryou and Sarah Falkus at the publishers, and, in the final stages, the considerable help given in the preparation of the final manuscript by Lucy Heath. All are thanked enormously. DSGT

vi

Preface to the First Edition The preparation of a dictionary of this complexity has involved many people, and all deserve thanks for the efficiency with which they have prepared their material on time and in the format required. We have been fortunate in having as a model our companion volume, The Dictionary of Human Geography, which was so expertly edited by RJ. Johnston and his team. I would like to express particular thanks to Janet Godden for having taken over so much of the organizational burden, and to Andrew Watson for being willing to prepare many of the short entries. ASG

vii

Introduction This dictionary provides definitions of terms and explanations of key ideas, concepts, and issues in physical geography. It draws upon the wealth of knowledge of over 90 contributors and is aimed for the use of professionals, students, teachers and researchers in geography and allied environmental and life sciences. Entries are organized alphabetically, but to aid further understanding, they are, where appropriate, cross-referenced to other relevant entries, which are shown in small capitals in the text. An index allows the identification of other entries in which a term is referred to, allowing a wider sense of its usage to be gained. Many entries are referenced and/or accompanied by suggestions for further reading. Together, this allows source material, examples of usage and extended explanations to be explored.

IX

Acknowledgements The editors and publishers wish to thank the following for permission to use copyright material. Addison Wesley Longman Limited for the figure in groundwater from Jones, Global hydrology: processes, resources and environmental management, 1997; reprinted by permission of Pearson Education Limited Blackwell Publishers Ltd for the figure in floristic realms from Goudie, The nature of the environment, 1993 Blackwell Science Ltd for the figure in carrying capacity from Begon, Harper and Townsend, Ecology) individuals, population and communities, 1986 David Bridgland for the figure in river terrace from Bridgland, Allen and Haggart (eds), The Quarternary of the lower reaches of the Thames: field guide, Quaternary Research Association, 1995 Butterworth Heinemann Publishers, a division of Reed Educational & Professional Publishing Ltd, for the figures in water lllass from Open University Oceanography Course Team, Ocean Circulation, 1989 Cambridge University Press and W.B. Harland for the table in geological time-scale from Harland, Armstrong, Cole, Craig, Smith and Smith, A geologic time scale 1989, 1990 Chapman & Hall for the table in Beaufort scale from Oliver and Fairbridge, The encyclopedia of climatology, 1987; and figures in global ocean circulation and water mass from Tolmazin, Elements of dynamic oceanography, 1985; with kind permission from K.1uwer Academic Publishers David Evans for the figure in crag and tail fOrllls from Benn and Evans, Glaciers and glaciation, 1998 Longman Group Ltd for figures and tables in plate tectonics, rift valley, stress and karren from Summerfield, Global geomorphology, 1991; and for the table in glaciofluvial from Price, Glacial and flu violglacial landforms, 1973, Oliver & Boyd Macmillan for the figure in association, plant from Whittaker, Communities and ecosystems, second edition, 1975 Routledge and C.C. Park for the figure in tropical rain forest from Parks, Tropical rainforests, 1992 The Geological Society for the table and figure in weathering profile from Fookes,

Tropical residual soils, 1997

Elsevier Science for the figure in pollen analysis from Behling and Hooghiemstra, in

Palaeogeography, palaeoclimatology and palaeoecology 139, pp. 251-67, 1998

Every effort has been made to trace copyright holders. The publishers apologize for any errors or omissions in the above list and will be pleased to make the necessary arrangement at the first opportunity. x

Contributors CAMK

Cuchlain A M King formerly of University of Nottingham

Allen H Perry University of Wales, Swansea

CDC

Chris D Clark University of Sheffield

A Henderson-Sellers MacQuarie University

CTA

Clive T Agnew University of Manchester

A Louise Heathwaite University of Sheffield

DB

Denys Brunsden formerly of King's College London

DES

David Sugden University of Edinburgh

DEW

DE Walling University of Exeter

DW

David Watts University of Hull

DGT

David G Tout University of Manchester

AD

Angus Duncan University of Luton

AHP

AH-S

ALH

AMG

Angela M Gurnell University of Birmingham

AP

Adrian Parker University of Oxford

ARH

Alan R Hill York University, Ontario

ASG

Andrew S Goudie University of Oxford

AW

Andrew Watson formerly University of Oxford

AWE

Andrew W Ellis Arizona State University

DH

David Higgitt University of Durham

BAK

Barbara A Kennedy University of Oxford

DJN

David J Nash University of Brighton

BGT

Bruce G Thom University of Sydney

DJS

Douglas Sherman University of Southern California

BJS

B J Smith Queen's University of Belfast

DLD

David L Dunkerley Monash University

DSGT

David S G Thomas University of Sheffield

BWA

B WAtkinson Queen Mary & Westfield College, London

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Index Notes 1 2 3

Page numbers in bold indicate definitions. Those in italics indicate illustrations, maps and tables. Specific places and species have been omitted as these are too numerous to include. Names of people are also omitted, unless they are important historically and mentioned often. Acronyms and initials are arranged alphabetically.

abandoned channels 203, 354 abandoned fields 288-9 abime 1 abiotic components 1 ablation 1, 99, 124, 226 balancing accumulation 179-80, 308 calving 1, 68 moraines 325 abrasion 1, 378 comminution 98, 490 facet 196 fluting 206 roche moutonnee 417 rock flour 417 roundness 421-2 ventifact 514 absolute age 1 absolute drought 148 absolute humidity 250 abundance 1 abyss 1 abyssopelagic zone 1, 345 acceleration 532 centripetal 232 and mass see force opposing (resistance) 408-9 see also mass strength; roughness; shear strength and velocity (Froude number) 215 accelerator mass spectroscopy 70-1, 76, 107 accessory mineral 1 accordant junctions, law of 1, 377 accordant summits 1-2 accretion 2, 403 lateral 203, 290, 379 accumulated temperature 2, 125 accumulation (glacial) 99, 179-80, 308 acid acidity profile (signal/record) 5 deposition 2-3,4, 150, 344 pesticides 367 pH 67, 368 precipitation 2,3,3-4, 135, 150, 338 rocks 4 see also igneous rocks susceptibility / acid neutralizing capacity 4-5 aclinic line 5 actinometer 5 active layer 5-6, 112, 365 frost creep 6, 214

540

see also frost heave; patterned ground active margin 6,467,471 see also earthquakes; orogeny activity (ratio) 6, 11 actual evaporation 185-6 actual evapotranspiration (AEt) 187-8, 448 actualism see Uniformitarianism adaptive radiation 6,198,275,515 adhesion ripple and warts 6 adiabatic processes 6-7, 372 clouds 94 condensation 100 general circulation of atmosphere 218 lapse rate 290 potential temperature 386 temperature inversion 481 thermodynamic equation 486 vorticity 518 winds see katabatic adobe 7 adret 7 adsorption 7, 69 advection 7, 105, 247 temperature inversion 273, 481 see also convection; fog; winds adventitious 7 aeolation 7-8 aeolian (eolian) 8, 408 see also winds aeolianite 8, 68,513 aeration zone 8 see also vadose aerial photography 8--9, 25, 305-6, 407 aerial camera 8 multispectral scanner superior to 329-30 photogrammetry 369 thermal infrared linescanner 269, 407, 485 see also satellites aerobic processes 9, 20 see also oxygen; respiration aerobiology 9 pollen analysis 9 aerodynamic ripples 10 aerography 10 aerology 10 aeronomy 10 aerosols 9, 10, 32, 372 in clouds, DMS as 137