Field techniques in glaciology and glaci

Field Techniques in Glaciology and

Glacial Geomorphology

Field Techniques in

Glaciology and Glacial

Geomorphology

Bryn Hubbard

Neil Glasser

Centre for Glaciology

University of Wales, Aberystwyth

Copyright
2005 John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester,

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Library of Congress Cataloging in Publication Data

Hubbard, Bryn.

Field techniques in glaciology and glacial geomorphology / Bryn Hubbard, Neil Glasser.

p. cm.

Includes bibliographical references and index.

ISBN-13 978-0-470-84426-7 (cloth : alk. paper) — ISBN-13 978-0-470-84427-4 (pbk. : alk. paper)

ISBN-10 0-470-84426-4 (cloth : alk. paper) — ISBN-10 0-470-84427-2 (pbk. : alk. paper)

1. Glaciology—Field work. I. Glasser, Neil F. II. Title.

GB2402.3.H64 2005

551.31007203—dc22

2004028501

British Library Cataloguing in Publication Data

A catalogue record for this book is available from the British Library

ISBN-13 978-0-470-84426-7 (HB) 978-0-470-84427-4 (PB)

ISBN-10 0-470-84426-4 (HB) 0-470-84427-2 (PB)

Typeset in 10/12pt Sabon by Integra Software Services Pvt. Ltd, Pondicherry, India

Printed and bound in Great Britain by TJ International Ltd, Padstow, Cornwall

This book is printed on acid-free paper responsibly manufactured from sustainable forestry in which at least

two trees are planted for each one used for paper production.

Contents

Preface ix

Acknowledgements xi

1 Introduction 1

1.1 Aim 1

1.2 The scope of this book 1

1.3 Book format and content 2

1.4 The role of fieldwork in glaciology and glacial

geomorphology 3

1.5 The relationship between field glaciology and

glaciological theory 4

2 Planning and conducting glaciological fieldwork 15

2.1 Aim 15

2.2 Designing and planning field-based research 15

2.3 Logistical preparations for fieldwork 20

2.4 Fieldwork data 26

3 Glacier ice: Character, sampling and analysis 30

3.1 Aim 30

3.2 Ice masses and ice facies: Principles, definition

and identification 30

3.3 Sampling glacier ice 38

3.4 Ice analysis 55

3.5 Student projects 63

4 Glacier meltwater: Character, sampling and analysis 65

4.1 Aim 65

4.2 Background 65

4.3 Measuring bulk meltwater discharge: Stage-discharge

rating curves 68

4.4 Sampling and analysing glacial meltwaters 79

4.5 Automated measurements by sensors and loggers 96

4.6 Tracer investigations 101

4.7 Student projects 112

5 Hot-water borehole drilling and borehole instrumentation 115

5.1 Aim 115

5.2 Introduction 115

5.3 Hot-water drilling 116

5.4 Borehole instrumentation 124

5.5 Summary 146

5.6 Student projects 146

6 Ice radar 148

6.1 Aim 148

6.2 Background and physical principles 148

6.3 Ice radar equipment 155

6.4 Radar data presentation 159

6.5 Field radar surveys 161

6.6 Processing 171

6.7 Field application and interpretation of ice radar 174

6.8 Student projects 177

7 Glacier mass balance and motion 179

7.1 Aim 179

7.2 Surface energy budget 180

7.3 Mass balance 187

7.4 Glacier motion and ice velocity 199

7.5 Student projects 216

8 Glacigenic sediments 217

8.1 Aim 217

8.2 Introduction to field sedimentology 217

8.3 Colour and organic content 226

8.4 Sediment texture 229

8.5 Particle morphology: The shape and roundness

of sedimentary particles 232

8.6 Bedding 239

8.7 Sedimentary structures 243

8.8 Palaeocurrent data 245

8.9 Other properties 246

8.10 Field sampling techniques 247

8.11 Fabric analysis: General considerations 251

8.12 Clast macrofabrics 252

8.13 Clast microfabrics and microstructural description 259

8.14 Clast mesofabrics 260

8.15 Laboratory analysis 260

8.16 Interpreting the environment of deposition

of sediments 262

vi CONTENTS

8.17 Presentation of sedimentological data 266

8.18 Student projects 267

9 Mapping glaciers and glacial landforms 269

9.1 Aim 269

9.2 General considerations 269

9.3 Aims of the mapping and the areal extent

of the map 270

9.4 Desk-based studies 271

9.5 Remotely sensed data 274

9.6 Geomorphological mapping 287

9.7 Field mapping 290

9.8 Field surveying techniques 304

9.9 Ground-penetrating radar and shallow seismic

reflection investigations of sediment bodies 308

9.10 Electrical resistivity surveys 311

9.11 Aquatic (marine and lacustrine) geophysical

techniques 313

9.12 Mapping glacier structures (structural glaciology) 321

9.13 Final map compilation 325

9.14 Mapping and measurement of landforms change

over time 327

9.15 Student projects 329

10 Monitoring and reconstructing glacier fluctuations 331

10.1 Aim 331

10.2 Remotely sensed images 332

10.3 Fieldwork mapping and historical documents 335

10.4 Dating glacier fluctuations using ‘absolute age’

(numerical-age) and ‘relative age’ estimates 339

10.5 Numerical-age dating techniques 340

10.6 Relative-age dating techniques 350

10.7 Dating glacier fluctuations – concluding remarks 364

10.8 Student projects 364

References 367

Index 396

CONTENTS vii

Preface

All geography and Earth science students carry out fieldwork during their

undergraduate degree, either on supervised field-courses or independently in

the form of an extended project such as a dissertation. Students and

researchers of glaciology and glacial geomorphology embarking on field￾work, many of them for the first time, currently do so without a standard

text informing them of accepted and practicable techniques for addressing

their chosen research topics. Currently, students therefore obtain such

information either by word of mouth or by searching the methods sections

of journals and research papers, neither of which is entirely adequate. At the

same time, readers of glaciological texts may be unaware of exactly how a

certain field data set was generated. In this book we provide information on

the techniques currently used to study the glacial environment. Our aim is to

provide an accessible text on how field glaciology and glacial geomorphol￾ogy are done rather than one on the theory of glaciology and glacial

geomorphology, which is adequately covered by existing texts. Thus, some

level of understanding of glaciology and glacial geomorphology is assumed

throughout the text. In providing a text on how aspects of glaciology and

glacial geomorphology are studied in the field we hope to provide informa￾tion that is relevant to two user groups: those who wish to carry out such

investigations themselves and those who wish to find out how information

was collected by others.

This book is designed primarily for glaciological investigations in high

latitudes rather than low latitudes. Thus, for example, our use of the term

‘winter season’ may be taken to mean ‘wet season’ at low latitudes. Con￾versely, our use of the term ‘summer season’ may be taken to mean ‘dry

season’ at low latitudes. We use the term glacier in its broadest sense, that is

to describe any substantial ice mass including valley glaciers, ice caps and

ice sheets. We also make the distinction between glacierized, describing

those areas still covered by glacier ice, and glaciated, describing formerly

glacierized areas (i.e. that are not currently glacierized).

By necessity, the discussion of field techniques is somewhat selective and

(unintentionally) biased towards the authors’ particular research areas and

operational scale. Thus, we limit our discussion to approaches and tech￾niques that are available to most researchers at a reasonable budget – and

many are explicitly included because of their availability to undergraduate

researchers. Thus, specialist, logistically demanding topics such as satellite￾based data collection and oceanography are not covered in any detail.

We also do not focus on snow investigations per se, for which excellent

method-based texts already exist (e.g. Gray and Male, 1981). This said, we

hope that we have covered the main techniques available to the majority of

today’s glaciologists and glacial geomorphologists.

Some of the methods described in this book are relatively simple; some

are much more complex. Some of the techniques are old; some are new.

Readers should be aware that change is constant in this rapidly developing

field. Technological advances will inevitably occur and many of the tech￾niques included in the text will change over time. Indeed, we are resigned to

the fact that some of the techniques included in the text will have been

superseded by the time of publication. Readers should not be afraid to

amend the methods outlined or to experiment with new methods. As one

reviewer of our original book proposal put it: ‘The best outcome of books

like this are that they attract newcomers and raise the level of standard

practice; the worst outcome is that they entomb the science and deaden

initiative.’ We hope to achieve the former without doing the latter.

x PREFACE

Acknowledgements

We thank the following people for providing comments on parts of this

book at various stages in its completion: Matthew Bennett, Paul Brewer,

James Etienne, Mike Hambrey, Duncan Quincy and Laurence Fearnley.

Thanks are due to many people who kindly shared with us information

about specific techniques in their research area: Sven Lukas for information

on geomorphological mapping; Duncan Quincy for information on remote

sensing techniques; and Becky Goodsell for information on mapping glacier

structures.

Neil Glasser wrote large portions of this book whilst on study leave in the

Department of Geography, University of Canterbury, Christchurch, New

Zealand. Thanks are due to everyone in Christchurch, in particular Wendy

Lawson and Ian Owens, for their hospitality there.

We would also like to thank all those people with whom we have spent

time in the field over the years: Matthew Bennett, Kevin Crawford, James

Etienne, Urs Fischer, Becky Goodsell, Dave Graham, Stephan Harrison,

Richard Hodgkins, Alun Hubbard, Dave Huddart, Bernd Kulessa, Krister

Jansson, Peter Jansson, Wendy Lawson, Doug Mair, Ben Mansbridge, Peter

Nienow, Tavi Murray, Anne-Marie Nuttall, Nick Midgley, Martin Sharp,

Martin Siegert, David Sugden, Richard Vann, Richard Waller, Jemma

Wadham, Charles Warren and Ian Willis.

We acknowledge the support and advice of all colleagues (both past and

present) at the Centre for Glaciology, University of Wales, Aberystwyth as

well as Ian Gulley and Antony Smith (Institute of Geography and Earth

Sciences, University of Wales, Aberystwyth) for drawing many of the

diagrams used in this book.

Bryn Hubbard and Neil Glasser

Aberystwyth

1

Introduction

1.1 AIM

The aim of this book is to provide students and researchers with a practical

guide to field techniques in glaciology and glacial geomorphology. Many

books and papers have been written about glaciology and glacial geomorph￾ology, but nearly all of these present the results of glaciological or geomorph￾ological studies rather than describing the methods by which these results

were achieved. We have written this book with three principal audiences

in mind: (1) undergraduate fieldtrip and dissertation students who may be

conducting fieldwork independently and for the first time, (2) undergraduates

studying a standard theoretical course in glaciology or glacial geomorphology,

whose understanding may be enhanced by knowledge of the techniques used

to achieve various theoretical outcomes, and (3) postgraduate research stu￾dents and professionals who may be designing field projects and equipment

and perhaps implementing them for the first time.

1.2 THE SCOPE OF THIS BOOK

Glaciology and glacial geomorphology are essentially field sciences and the

emphasis of this book is therefore on fieldwork. We recognize that not all

problems can be solved by field research, partly because of the complexity of

glaciological and geomorphological problems in nature and partly because

not all problems lend themselves readily to investigation in the field. Some

properties of glaciers are difficult or time-consuming to measure in the field

(e.g. patterns of spectral reflectance, temporal changes in altitude or velocity,

Field Techniques in Glaciology and Glacial Geomorphology Bryn Hubbard and Neil Glasser

2005 John Wiley & Sons, Ltd