ENCYCLOPEDIA OF GEOLOGY ENCYCLOPEDIA OF GEOLOGY EDITED BY RICHARD C. SELLEY L. ROBIN M. COCKS IAN R. PLIMER ELSEVIER ACADEMIC PRESS Amsterdam Boston Heidelberg London New York Oxford Paris San Diego San Francisco Singapore Sydney Tokyo Elsevier Ltd., The Boulevard, Langford Lane, Kidlington, Oxford, OX5 1GB, UK © 2005 Elsevier Ltd. The following articles are © 2005, The Natural History Museum, London, UK: FOSSIL VERTEBRATES/Hominids Palaeontology PALAEOZOIC/Silurian PRECAMBRIAN/Overview Terranes, Overview Conservation of Geological Specimens MINERALS/Olivines MINERALS/Sulphates TERTIARY TO PRESENT/Pleistocene and The Ice Age Environmental Geochemistry Biological Radiations and Speciation PALAEOZOIC/Ordovician TERTIARY TO PRESENT/Eocene TERTIARY TO PRESENT/Paleocene FOSSIL PLANTS/Angiosperms FOSSIL PLANTS/Gymnosperms Biozones MESOZOIC/Cretaceous MESOZOIC/End Cretaceous Extinctions Stratigraphical Principles FOSSIL INVERTEBRATES/Molluscs Overview FOSSIL INVERTEBRATES/Trilobites FOSSIL INVERTEBRATES/Echinoderms (Other Than Echinoids) FOSSIL INVERTEBRATES/Echinoids TERTIARY TO PRESENT/Pliocene FOSSIL INVERTEBRATES/Bryozoans MINERALS/Feldspathoids Russia The following article is a US Government work in the public domain and not subject to copyright: NORTH AMERICA/Atlantic Margin "Earth from Space" endpaper figure reproduced with permission from Reto Stockli, Nazmi El Saleous, and Marit Jentoft-Nilsen and NASA GSFC All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publishers. Permissions may be sought directly from Elsevier's Rights Department in Oxford, UK: phone (+44) 1865 843830, fax (+44) 1865 853333, [email protected]. Requests may also be completed on-line via the homepage (http://www.elsevier.com/locate/permissions). First edition 2005 Library of Congress Control Number: 2004104445 A catalogue record for this book is available from the British Library ISBN 0-12-636380-3 (set) This book is printed on acid-free paper Printed and bound in Spain EDITORS v Editors EDITORS Richard C. Selley Imperial College London, UK L. Robin M. Cocks Natural History Museum London, UK Ian R. Plimer University of Melbourne Melbourne, VA Australia CONSULTANT EDITOR Joe McCall Cirencester Gloucestershire, UK vi EDITORIALADVISORYBOARD Editorial Advisory Board Jaroslav Aichler Georg Hoinkes Czech Geological Survey Universita¨t Graz Jesenı´k, Czech Republic Universita¨tplatz 2 Graz, Austria Andrew RArmour Revus Energy A/S RA Howie Royal Holloway, London University Norway London, UK John Collinson ShunshoIshihara Delos, Beech Geological Survey of Japan Staffordshire, UK Tsukuba, Japan AlexanderM Davis GilbertKelling Infoscape Solutions Ltd. Keele University Guildford, UK Keele, UK Ken Macdonald PeterDoyle University of California Santa Barbara University College London Santa Barbara, CA, USA London, UK Norman MacLeod Wolfgang Franke The Natural History Museum Institut fu¨r Geowissenschaften London, UK Giessen, Germany Stuart Marsh YvesFuchs British Geological Survey Universite´ Marne la Valle Nottingham, UK France Joe McCall Cirencester, Gloucestershire, UK PaulGarrard Formerly Imperial College London, UK David ROldroyd University of New South Wales Sydney, NSW, Australia RO Greiling Universita¨t Heidelberg Heidelberg, Germany Rong Jia-yu Nanjing Institute of Geology and Palaeontology Nanjing, China Gwendy Hall Natural Resources Canada Mike Rosenbaum Ottawa, ON, Canada Twickenham, UK Robert DHatcher, Jr. Peter Styles University of Tennessee Keele University Knoxville, TN, USA Keele, UK EDITORIALADVISORYBOARD vii HansDSues SHWhite Carnegie Museum of Natural History Universiteit Utrecht Pittsburgh, PA, USA Utrecht, The Netherlands JohnVeevers Macquarie University Sydney, NSW, Australia FOREWORD ix Foreword Fewareasofsciencecanhavechangedasfastasgeologyhasinthepastfortyyears.Inthefirsthalfofthelast centurygeologistsweredivided,oftenbitterly,betweenthedriftersandthosewhobelievedthattheEarthand its continents were static. Neither side of this debate foresaw that the application of methods from physics, chemistry and mathematics to these speculations would revolutionize the study of all aspects of the Earth Sciences,andwouldleadtoaccurateanddetailedreconstructionsofworldgeographyatformertimes,aswell as to an understanding of the origin of the forces that maintain the continental movements. This change in world-viewisnolongercontroversial,andisnowembeddedineveryaspectoftheEarthSciences.Itisareal pleasure to see this change, which has revitalized so many classic areas of research, reflected in the articles ofthisencyclopedia.Particularlyaffectedarethearticlesonlarge-scaleEarthprocesses,whichdiscussmany of the new geological ideas that have come from geophysics and geochemistry. Forty years ago we had no understanding of these topics, which are fundamental to so many aspects of the Earth Sciences. The editors havedecided,andinmyviewquiterightly,nottoincludedetaileddiscussionofthepresenttechnologythatis usedtomakegeophysicalandgeochemicalmeasurements.Suchinstrumentalaspectsarechangingrapidlyand becomedatedveryquickly.Theycaneasilybefoundinmoretechnicalpublications.Insteadtheeditorshave concentratedontheinfluencesuchstudieshavehadonourunderstandingoftheEarthanditsevolution,andin sodoinghaveproducedanexcellentandaccessibleaccountofwhatisnowknown. Anyencyclopediahastosatisfyawidevarietyofusers,andinparticularthosewhoknowthatsomesubject likesedimentationormineralexplorationispartofgeology,andgotoanencyclopediaofgeologytofindout more.Theeditorshavemadeaverythoroughattempttosatisfysuchusers,andhaveincludedsectionsonsuch unexpected geological topics as the evolution of the Earth’s atmosphere, the geology of Jupiter, Saturn, and their moons, aggregates, and creationism. I congratulate the editors and authors for producing such a fine summaryofourpresentknowledge,andamparticularlypleasedthattheyintendtoproduceanonlineversion oftheencyclopedia.ThoughIhavebecomeaddictedtousingtheInternetasmygeneralencyclopedia,Iwillbe delightedtobeabletoaccesssomethingconcernedwithmyownfieldthatisasorganizedandscholarlyasare thesevolumes. DanMcKenzie RoyalSocietyProfessorofEarthSciences CambridgeUniversity,UK