tailieunhanh - A Dictionary of Earth Sciences third edition

absolute pollen frequency (APF) *Pollen data from sediments, expressed in terms of the absolute numbers for each *species, *genus, or *family, per unit volume of sedi- ment and, where deposition rates are known, per unit time. In certain circumstances this approach gives clearer information than does the traditional way of expressing pollen data as *relative pollen frequencies (RPFs). APFs are particularly useful in site comparisons in which one or more high pollen producers vary. For example, when trees first appear in the regional pollen rain their prolific pollen may, in an RPF method, give the impression of declining herbaceous species, whereas exami- nation by an APF method will show constant values for herb species | A WIDE RANGING AND AUTHORITATIVE GUIDE CONTAINING OVER 6 250 ENTRIES Oxford r DICTIONARY OF Earth I Sciences J s X MICHAEL ALLABY A Dictionary of Earth Sciences THIRD EDITION Edited by MICHAEL ALLABy OXTORD UNIVERSITY PRESS 03 UNIVERSITY PRESS Great Clarendon Street Oxford 0X2 ỖDP Oxford University Press is a department of the University of Oxford. It furthers the University s objective of excellence in research scholarship and education by publishing worldwide in Oxford New York Auckland Cape Town Dar es Salaam Hong Kong Karachi Kuala Lumpur Madrid Melbourne Mexico City Nairobi New Delhi Shanghai Taipei Toronto With offices in Argentina Austria Brazil Chile Czech Republic France Greece Guatemala Hungary Italy Japan Poland Portugal Singapore South Korea Switzerland Thailand Turkey Ukraine Vietnam Oxford is a registered trademark of Oxford University Press in the UK and in certain other countries Published in the United States by Oxford University Press Inc. New York Oxford University Press 1990 1999 2003 2008 The moral rights of the authors have been asserted Database right Oxford University Press maker First published 1990 First issued as an Oxford University Press paperback 1991 Second edition 1999 Reissued with new covers and corrections 2003 Third edition 2008 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 without the prior permission in writing of Oxford University Press or as expressly permitted by law or under terms agreed with the appropriate reprographics rights organization. Enquiries concerning reproduction outside the scope of the above should be sent to the Rights Department Oxford University Press at the address above You must not circulate this book in any other binding or cover and you must impose this same condition on any acquirer British Library Cataloguing in Publication Data Data available Library of Congress Cataloging in Publication Data Data available