An Introduction To Marine Geology

C.S.S. Hudson: photograph courtesy of the Department of Energy, Mines and Resources of Canada. An Introduction to Marine Geology by M. J . KEEN ASSOCIATE PROFESSOR, I N S T I T U T E OF O C E A N O G R A P H Y , DALHOUSIE U N I V E R S I T Y , H A L I F A X , NOVA SCOTIA PERGAMON PRESS OXFORD · NEW YORK · TORONTO SYDNEY · BRAUNSCHWEIG Pergamon Press Ltd., Headington Hill Hall, Oxford Pergamon Press Inc., Maxwell House, Fairview Park, Elmsford, New York 10523 Pergamon of Canada Ltd., 207 Queen's Quay West, Toronto 1 Pergamon Press (Aust.) Pty. Ltd., 19a Boundary Street, Rushcutters Bay, N.S.W. 2011, Australia Vieweg & Sohn GmbH, Burgplatz 1, Braunschweig Copyright © 1968 Pergamon Press Ltd. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of Pergamon Press Limited. First edition 1968 Reprinted 1969 Reprinted 1970 Library of Congress Catalog Card No. 67 - 26689 Printed in Great Britain by Hazell Watson & Viney Ltd., Aylesbury, Bucks and reprinted lithographically by A. Wheaton & Co., Exeter, Devon This book is sold subject to the condition that it shall not, by way of trade, be lent, resold, hired out, or otherwise disposed of without the publisher's consent, in any form of binding or cover other than that in which it is published. 08 012505 O(flexicover) 08 012506 9 ( h a r d cover) Preface I have attempted to present an account of some aspects of marine geology and marine geophysics, comprehensible to those at an early stage in their study of geology, and to scientists who are not specialists in these fields. There are many who, being biologists, chemists, mathematicians or physicists, work in the laboratory or on board ship with geologists and geophysicists, and this book may help them to understand the aims of their colleagues' experiments. I have not hesitated to simplify terminology where there is no loss of necessary precision. No attempt has been made to present a full account of all possible aspects of marine geology that might be considered, and I have not referred to near-shore processes at all. Many sections are explanatory and will be familiar to any geologist who by chance reads the book; he should, of course, turn the pages until he finds something less familiar to him. Dalhousie University Halifax, Nova Scotia M. vii J . KEEN N O T E T o FIRST REPRINT Ideas about ocean-floor spreading developed rapidly during the production of this book. The references listed below may help the reader. Some are already referred to, and are collected here for convenience. The readers attention is also drawn to The Sea, Vol. iv, to appear in 1969. Bullard, E. C , Reversals of the earth's magnetic field, Phil. Trans. Roy. Soc. Lond. A 2 6 3 , 4 8 1 - 5 2 4 (1968) Isacks, B., Oliver, J . and Sykes, L. R., Seismology and the new global tectonics, Jour. Geophys. Res. 73, 5 8 5 5 - 5 9 0 0 (1968) Le Pinchon, X . , Viscosity of the mantle from relaxation time spectra of isostatic adjustment, Jour. Geophys. Res. 73, 3 6 6 1 - 3 6 9 8 (1968) Mckenzie, D. P., Some remarks on heat flow and gravity anomalies, Jour. Geophys. Res. 7 2 , 6 2 6 1 - 6 2 7 4 (1967) McKenzie, D. and Parker, R. L., The North Pacific: an example of tectonics on a sphere, Nature 216, 1 2 7 6 - 1 2 8 0 (1967) Morgan, W. J . , Rises, trenches, great faults, and crustal blocks, Jour. Geophys. Res. 73, 1 9 5 9 - 1 9 8 2 (1968) Sykes, L. R., Mechanism of earthquakes and nature of faulting on the mid-oceanic ridges,/owr. Geophys. Res. 72, 2 1 3 1 - 2 1 5 3 (1967) Vine, F . J . and Mathews, D. H., Magnetic anomalies over ocean ridges, Nature 199, 9 4 7 - 9 4 9 (1963) Wilson, J . T