Antarctic Marine Geology

298 Pages·1999·77.87 MB·English

by  John B. Anderson

Antarctic Marine Geology
The fragile Antarctic environment consists of a closely linked system of the
lithosphere, atmosphere, cryosphere, hydrosphere and biosphere. Changes in
this system have influenced global climate, oceanography and sea level for most
of Cenozoic time. The geological history of this region therefore provides a
special record of important interactions between the various components of
the Earth System.
Antarctic Marine Geology is the first comprehensive single-authored book
to introduce students and researchers to the geological history of the region
and the unique processes that occur there. The Antarctic geological literature
is widely disseminated, and until now no single reference has existed which
provides such a summary. The book is intended as a reference for all scientists
working in Antarctica, and will also serve as a textbook for graduate courses
in Antarctic marine geology.
John B. Anderson has worked in Antarctica for 29 years, and he has partici-
pated in 19 scientific expeditions. He has published over 100 refereed papers,
most dealing with Antarctic marine geology. He is a former member of the
Polar Research Board and 1997 NSF-OPP External Panel. Anderson received
the 1996 Rice University graduate teaching award and the 1992 Gulf Coast
Association of Geological Societies Outstanding Educator Award.

Antarctic
Marine
Geology
JOHN B. ANDERSON
Rice University
h
\
•**
??' ^tv
CAMBRIDGE
UNIVERSITY PRESS
CAMBRIDGE UNIVERSITY PRESS
Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore,
Sao Paulo, Delhi, Dubai, Tokyo
Cambridge University Press
The Edinburgh Building, Cambridge CB2 8RU, UK
Published in the United States of America by Cambridge University Press, New York
www.cambridge.org
Information on this title: www.cambridge.org/9780521131681
© Cambridge University Press 1999
This publication is in copyright. Subject to statutory exception
and to the provisions of relevant collective licensing agreements,
no reproduction of any part may take place without the written
permission of Cambridge University Press.
First published 1999
This digitally printed version 2010
A catalogue record for this publication is available from the British Library
Library of Congress Cataloguing in Publication data
Anderson, John B., 1944-
Antarctic marine geology / John B. Anderson.
p. cm.
Includes index.
ISBN 0-521-59317-4 (hardback)
1. Geology -Antarctica. 2. Submarine geology. I. Title.
QE350.A49 1999
559.8'9-dc21 98-37219
CIP
ISBN 978-0-521-59317-5 Hardback
ISBN 978-0-521-13168-1 Paperback
Cambridge University Press has no responsibility for the persistence or
accuracy of URLs for external or third-party internet websites referred to in
this publication, and does not guarantee that any content on such websites is,
or will remain, accurate or appropriate.
Contents
CHAPTER 1
Antarctica's Environment page 1
Antarctica's role in the global
environment, 1 • Present glacial setting, 6
• Weather and Climate, 20 • Physical
oceanographic setting, 23
CHAPTER 2
Geologic History of Antarctica 28
General structure and components of
Antarctica, 28 • Orogenic events affecting
East and West Antarctica, 30 • Reconstruction
of Gondwana, 36 • Breakup and dispersal of
Gondwana, 40 • Antarctic stratigraphy, 43
CHAPTER 3
Continental Shelf Geomorphology
and Relief-Forming Processes 58
Why is the continental shelf so deep?, 58
• Geomorphology, 63 • Regional studies,
72 • Summary, 88
CHAPTER 4
Sedimentology 89
Subglacial environment, 89 • Grounding
zone environment, 101 • Ice shelf
environment, 106 • Ice cliff environment,
112* Ice-free coasts, 113* Proglacial
marine environment, 113* Bay and fjord
environments, 120 • Continental slope and
rise environment, 127 • Abyssal environment,
131 • Case studies, 134
CONTENTS
CHAPTER 5
Continental Margin Evolution 155
Ross Sea, 155 • Pacific-Antarctic margin,
169 • Bransfield Basin, 179 • Western
Weddell Sea margin, 185 • Eastern Weddell
Sea margin, 190 • Wilkes Land, 196 • Prydz
Bay, 202 • Summary, 205
CHAPTER 6
Antarctica's Glacial History 207
Using "proxy" criteria to define Antarctica's
glacial history, 207 • Continental and
continental shelf record of ice sheet evolution,
217 • History of the Antarctic cryosphere,
223 • Late Quaternary ice sheet activity:
Case studies, 235 • Summary, 247
Bibliography 249
Index 287
Acknowledgments
This book draws heavily from the theses and dissertations valuable editorial assistance and David Matty and Robyn
of my graduate students who have traveled to the Antarc- Wright Dunbar contributed to the writing of Chapter 2.
tic with me to collect data, have conducted most of the Stephanie Shipp, Nicki Atkinson, Ashley Lowe and Breezy
analyses of these data, and have been a constant source Long drafted the figures for the book and assisted with
of inspiration these past two decades. I owe a special other technical aspects of publication.
word of thanks to all of them. Thank you Barbara An- I also want to express my gratitude to the crews and
drews, Mohammed Baegi, Laura Banfield, Phil Bart, Lou technical support staff from all my cruises on the USCGC
Bartek, Kathy Balshaw Biddle, Chris Brake, Jana DaSilva, Glacier, ARA Islas Orcadas, R/V Polar Duke, and the
Laura De Santis, Eugene Domack, Robyn Wright Dun- R/V NB Palmer. Their dedication and highly professional
bar, Pam Fisco, Tom Griffith, Elke Jahns, John Jeffers, support has made all my ventures to Antarctica reward-
Doug Kennedy, Dennis Kurtz, Margaret Herron, Ashley ing experiences. I appreciate the support of the Antarctic
Lowe, Scott MacDonald, Robert Milam, Nathan My- Marine Geology Research Facility, particularly Dennis
ers, Peter Pope, David Reid, Tony Rodriguez, Christina Cassidy and Tom Janecek, for providing samples and be-
Roqueplo, Stephanie Shipp, Jill Singer, Fernando Siringan, ing so helpful during our many visits to the facility to
Mike Smith, Mark Thomas and Julia Wellner. I cannot be- study the Antarctic core collections. My research during
gin to list my colleagues in the field who have contributed the past two decades has been funded by the National
through stimulating discussion and interaction. Science Foundation-Office of Polar Programs.
I owe a special word of thanks to Stephanie Shipp, who Lastly, I must thank my wife Doris and my children
edited several versions of the book and helped with its John and Heather for their love, encouragement and sup-
overall organization. She saw this project through to the port. They spent many winters at home while I was in
end. Thank you Stephanie. Antarctica. And lastly, thanks to my mother and father,
Michelle Fassell, Charlotte Kelchner, Ashley Lowe, Walter and Lena Anderson, who have always inspired me
Tony Rodriguez, Cindy Ross and Julia Wellner provided by their positive outlooks on life.

CHAPTER ONE
Antarctica's Environment
This chapter introduces the reader to the various com- from the Antarctic coast. Even early humans may have
ponents of Antarctica's glacial, atmospheric, and oceano- responded to its influence (Denton, Prentice, and Burckle,
graphic environment. It is not intended as an in-depth 1991). Conversely, there is little doubt that human beings
treatment of these subjects. Rather, this chapter is intended have seriously altered the fragile ecosystem of the Southern
to provide marine geologists with sufficient information to Ocean by uncontrolled harvesting of seals, whales, finfish,
focus on and solve problems related to sedimentary pro- and krill.
cesses and to examine the stratigraphic record as it relates Tectonic activity on the continent, especially the up-
to changes in the Antarctic environment. It is also intended lift of the Transantarctic Mountains (TAM), strongly in-
to provide the information needed to plan and execute suc- fluenced the early evolution of the Antarctic Ice Sheet
cessful marine geologic and geophysical expeditions. (Fig. 1.1). Eventually, the TAM formed a physiographic
boundary between the East and West Antarctic ice sheets.
These ice sheets have had a very different evolution and
ANTARCTICA'S ROLE IN THE are still quite different in terms of their size, shape, and
GLOBAL ENVIRONMENT dynamics: these differences are, in large part, due to their
different geologic settings.
Isolated from other continents by the Southern Ocean The Antarctic atmosphere-cryosphere-lithosphere sys-
(oceans south of ~60° S), Antarctica is the only continent tem constantly changes, continuously influencing the glob-
that experiences a true polar climate. The Antarctic Ice al system. On a short-term scale, Antarctica serves as an
Sheet is almost as large as it was during the last glacial atmospheric heat sink causing the temperature gradient
maximum, containing at least 80% of its previous volume that drives atmospheric circulation in the Southern Hemi-
(Denton and Hughes, 1981). Thus, Antarctica provides a sphere (Mullan and Hickman, 1990). The stable upper-
modern setting in which to study "Ice Age" Earth. Antarc- atmospheric air mass that resides over the continent has
tica claims a long history of Cenozoic glaciation and has been seriously altered by manufactured chemicals, result-
played a key role in regulating world climate, oceanogra- ing in the creation of the well-known Antarctic Ozone
phy, and eustasy for most of this geologic era. Hole (Farman, Gardiner, and Shanklin, 1985; Solomon
Antarctica's lithosphere, atmosphere, cryosphere, hy- et al., 1986). In addition, ice core records provide evi-
drosphere, and biosphere are closely linked and have been dence that the quantity of atmospheric greenhouse gases
for much of the continent's glacial history, but the con- (CO2 and CH4) has increased markedly during the past
tinent has not always been glaciated. During the Creta- 200 years and that these gases are presently more abun-
ceous, the coastal regions of Antarctica supported lush, dant than at any time in the past 160,000 years (Oeschger
temperate forests inhabited by a wide diversity of ani- and Siegenthaler, 1988; Lorius, Jouzel, and Raynaud,
mals. At that time, the continent was situated at a latitude 1993).
similar to southern South America. As Antarctica drifted Sea-ice growth and decay around Antarctica influence
away from the other Gondwana continents and toward climate and ocean circulation throughout much of the
the south, its climate cooled and daylight hours became Southern Hemisphere. The temperature gradient associ-
more seasonally distributed. The evolutionary changes of ated with Antarctica's sea-ice zone is one of the strongest
plants and animals trying to adapt to these harsher con- on Earth. The oscillating sea-ice canopy around Antarc-
ditions on the continent are among the most spectacular tica is intimately associated with surface water masses
and poorly understood paleontologic events in Earth's ge- and is the primary regulator of the ocean's vertical heat
ologic history. There were also significant changes in wa- flux and stability (Mullan and Hickman, 1990; Martinson
ter mass properties and circulation patterns in the South- and Iannuzzi, 1998). Predicted global warming trends are
ern Ocean, and these changes influenced organisms far expected to reduce significantly the areal extent of this