Marine Geochemistry

522 Pages·2000·5.652 MB·English

by  Roy Chester

Marine Geochemistry
Roy Chester
Department of Earth Sciences, University of Liverpool
SECOND EDITION

Blackwell
Science

Marine Geochemistry
This book is dedicated with affection and gratitude
to Dr G. D. Nicholls, an innovative geochemist, and
a fine teacher who has the truly rare gift of being
able to inspire his students
Marine Geochemistry
Roy Chester
Department of Earth Sciences, University of Liverpool
SECOND EDITION

Blackwell
Science
© 2000 by The right of the Author to be distributors
Blackwell Science Ltd identified as the Author of this Work Marston Book Services Ltd
Editorial Offices: has been asserted in accordance PO Box 269
Osney Mead, Oxford OX2 0EL with the Copyright, Designs and Abingdon, Oxon OX14 4YN
25 John Street, London WC1N 2BL Patents Act 1988. (Orders:Tel: [phone]
23 Ainslie Place, Edinburgh EH3 6AJ Fax: [phone])
350 Main Street, Malden All rights reserved. No part of
MA 02148-5018, USA this publication may be reproduced, USA
54 University Street, Carlton stored in a retrieval system, or Blackwell Science, Inc.
Victoria 3053, Australia transmitted, in any form or by any Commerce Place
10, rue Casimir Delavigne means, electronic, mechanical, 350 Main Street
75006 Paris, France photocopying, recording or otherwise, Malden, MA 02148-5018
except as permitted by the UK (Orders:Tel: [phone]
Other Editorial Offices: Copyright, Designs and Patents Act 781 388 8250
Blackwell Wissenschafts-Verlag GmbH 1988, without the prior permission Fax: [phone])
Kurfürstendamm 57 of the copyright owner.
10707 Berlin, Germany Canada
A catalogue record for this title Login Brothers Book Company
Blackwell Science KK is available from the British Library 324 Saulteaux Crescent
MG Kodenmacho Building Winnipeg, Manitoba R3J 3T2
ISBN 0-632-05432-8
7–10 Kodenmacho Nihombashi (Orders:Tel: [phone])
Chuo-ku, Tokyo 104, Japan
Library of Congress Australia
First published 1990 by Unwin Cataloging-in-publication Data Blackwell Science Pty Ltd
Hyman Ltd 54 University Street
Reprinted 1993 by Chapman & Chester, R. (Roy), 1936– Carlton, Victoria 3053
Hall Ltd Marine geochemistry/Roy (Orders:Tel: [phone]
Second edition 2000 Chester.—[2nd ed.] Fax: [phone])
p. cm.
Set by SNP Best-set Typesetter Ltd., Includes index. For further information on
Hong Kong ISBN 0-632-05432-8 Blackwell Science, visit our website:
Printed and bound in Great Britain 1. Chemical oceanography. 2. www.blackwell-science.com
by MPG Books Ltd, Bodmin, Marine sediments.
Cornwall 3. Geochemistry.
I. Title.
The Blackwell Science logo is a GC111.2.C47 1999
trade mark of Blackwell Science Ltd, 551.46¢01—dc21

registered at the United Kingdom
Trade Marks Registry
Contents
Preface to the first edition, vii 5.2 Hydrothermal activity: low-temperature
basalt–seawater reactions, 95
Preface to the second edition, viii 5.3 The hydrothermal pathway: summary, 96
Acknowledgements, x 6 The transport of material to the oceans:
relative flux magnitudes, 98
Symbols and concentration units, xi 6.1 River fluxes to the oceans, 98
6.2 Atmospheric fluxes to the oceans, 106
List of abbreviations and acronyms, xiii
6.3 Hydrothermal fluxes to the oceans, 117
6.4 Relative magnitudes of the primary fluxes to the
1 Introduction, 1
oceans, 120
1.1 Setting the background: a unified ‘process-
6.5 Relative magnitudes of the primary fluxes to the
orientated’ approach to marine geochemistry, 1
oceans: summary, 131
Part I: The Global Journey:
Part II: The Global Journey:
Material Sources
the Ocean Reservoir
2 The input of material to the ocean reservoir, 7 Descriptive oceanography: water-column
9
parameters, 137
2.1 The background, 9
7.1 Introduction, 137
7.2 Some fundamental properties of sea water,
3 The transport of material to the oceans:
137
the river pathway, 11
7.3 Oceanic circulation, 144
3.1 Chemical signals transported by rivers, 11
7.4 Tracers, 148
3.2 The modification of river-transported signals at
7.5 An ocean model, 155
the land–sea interface: estuaries, 26
7.6 Characterizing oceanic water-column sections, 156
7.7 Water-column parameters: summary, 163
4 The transport of material to the oceans:
the atmospheric pathway, 52 8 Dissolved gases in sea water, 165

4.1 Material transported via the atmosphere: the 8.1 Introduction, 165
marine aerosol, 52 8.2 The exchange of gases across the air–sea
4.2 The chemistry of the marine aerosol, 69 interface, 165
4.3 Material transported via the atmosphere: the 8.3 Dissolved oxygen in sea water, 172
air–sea interface and the sea-surface microlayer, 8.4 Dissolved carbon dioxide in sea water: the
81 dissolved CO cycle, 176
2
4.4 The atmospheric pathway: summary, 83 8.5 Dissolved gases in sea water: summary, 196
5 The transport of material to the oceans: 9 Nutrients, organic carbon and the carbon
the hydrothermal pathway, 88 cycle in sea water, 200
5.1 Hydrothermal activity: high-temperature 9.1 The nutrients and primary production in sea
basalt–seawater reactions, 88 water, 200
v
vi Contents
9.2 Organic matter in the sea, 219 13.6 Chemical signals to marine sediments, 355
9.3 The marine organic carbon cycle, 232 13.7 Marine sediments: summary, 355
9.4 Organic matter in the oceans: summary, 236
14 Sediment interstitial waters and diagenesis,
10 Particulate material in the oceans, 242 357
10.1 The measurement and collection of oceanic total 14.1 Early diagenesis: the diagenetic sequence and
suspended matter, 242 redox environments, 357
10.2 The distribution of total suspended matter in the 14.2 Organic matter in marine sediments, 364
oceans, 242 14.3 Early diagenesis in marine sediments, 369
10.3 The composition of oceanic total suspended 14.4 New concepts in organic matter preservation in
matter, 246 marine sediments, 373
10.4 Total-suspended-matter fluxes in the oceans, 249 14.5 Diagenesis: summary, 378
10.5 Down-column changes in the composition of 14.6 Interstitial water inputs to the oceans, 378
oceanic TSM and the three-layer distribution 14.7 Interstitial water inputs to the oceans: summary,
model, 252 402
10.6 Particulate material in the oceans: summary, 255
15 The components of marine sediments,
11 Trace elements in the oceans, 258 405
11.1 Introduction, 258 15.1 Lithogenous components, 405
11.2 Oceanic residence times, 261 15.2 Biogenous components, 410
11.3 An oceanic trace-metal framework, 263 15.3 ‘Hydrogenous’ components: halmyrolysates
11.4 Geographical variations in the distributions of and precipitates, 420
trace elements in surface ocean waters: 15.4 Cosmogenous components, 437
coastal–open-ocean horizontal gradients, 264 15.5 Summary, 438
11.5 The vertical distribution of trace elements in the
water column, 271 16 Unscrambling the sediment-forming
11.6 Processes controlling the removal of trace chemical signals, 442
elements from sea water, 281 16.1 Definition of terminology, 442
11.7 Trace elements in sea water: summary, 306 16.2 The biogenous signal, 444
16.3 The detrital signal, 445
12 Down-column fluxes and the benthic 16.4 The authigenic signal, 445
boundary layer, 311 16.5 Unscrambling the detrital and authigenic signals,
12.1 Down-column fluxes, 311 445
12.2 The benthic boundary layer: the sediment–water 16.6 Signal spikes, 459
interface, 328 16.7 The ocean-wide operation of the sediment-
12.3 Down-column fluxes and the benthic boundary forming signals, 468
layer: summary, 333 16.8 Unscrambling the sediment-forming chemical
signals: summary, 476
Part III:The Global Journey:Material Sinks

Part IV: The Global Journey:
13 Marine sediments, 341
Synthesis
13.1 Introduction, 341
13.2 The formation of deep-sea sediments, 346 17 Marine geochemistry: an overview, 481
13.3 A general scheme for the classification of marine 17.1 How the system works, 481
sediments, 350 17.2 Balancing the books, 484
13.4 The distribution of marine sediments, 351 17.3 Conclusions, 488
13.5 The chemical composition of marine sediments,
351 Index, 493
Preface to the first edition
The past two or three decades have seen many impor- covering the geochemistry of oceanic sediments, and
tant advances in our knowledge of the chemistry, Dr G. Wolff for his invaluable advice on the organic
physics, geology and biology of the oceans. It has also geochemistry of biota, water and sediments. It is
become apparent that in order to understand the a great pleasure to acknowledge the help of Dr
manner in which the oceans work as a ‘chemical K. J. T. Murphy, who gave so freely of his time at
system’, it is necessary to use a framework which all stages in the preparation of the text. I also thank
takes account of these interdisciplinary advances. all those authors who have kindly allowed their
Marine Geochemistry has been written in response diagrams and tables to be reproduced in the book.
to the need for a single state-of-the-art text that Many other people have influenced the way in which
addresses the subject of treating the sea water, sedi- my thoughts have developed over the years, and to
ment and rock reservoirs as a unified system. In these friends and colleagues I owe a great debt of
taking this approach, a process-orientated frame- gratitude.
work has been adopted in which the emphasis is I would like to thank Unwin Hyman for their
placed on identifying key processes operating within understanding during the preparation of the volume;
the ‘unified ocean’. In doing this, particular attention Roger Jones for helping to develop the idea in the
has been paid to making the text accessible to stu- beginning, and Andy Oppenheimer, whose patience
dents from all disciplines in such a way that future in handling the manuscript has known no bounds.
advances can readily be understood. Finally, I would like to express my gratitude to my
I would like to express my thanks to those people wife Alison, for all the devoted support she has given
who have helped with the writing of this volume. me during the writing of this book and at all other
In particular, I wish to put on record my sincere times.
appreciation of extremely helpful suggestions made
by Professor John Edmond, FRS.In addition, I thank R. Chester
Dr S. Rowlatt for his comments on the sections Liverpool

vii
Preface to the second edition
The first edition of Marine Geochemistrywas written 3 The transport of particulate material to the interior
in response to the need for a single state-of-the-art of the ocean. Many of the Global Ocean Flux Study
text that treats the oceans as a unified system. The (GOFS) regional sediment-trap studies have been
original concept used an approach in which the reported in the literature since the first edition was
emphasis was placed on identifying key processes written, thus allowing a quantitative estimate of
operating within the ‘unified ocean’, and the format down-column fluxes to be made on an ocean-wide
was designed to accommodate future advances in the scale.
subject. Since the first edition was written there have 4 Primary production and iron limitation. A better
in fact been significant advances in several areas of understanding has now emerged of the status of dif-
marine geochemistry and the text of the present ferent oceanic regions in marine primary productiv-
edition has been modified to accommodate them, ity, and particularly on the potentially limiting role
while still retaining the original formula. Some of the played by the micronutrient iron in areas where pro-
modifications are essentially no more than ‘fine duction is low in relation to the amount of the nutri-
tuning’. In contrast, others are more fundamental, ents available; i.e. the HNLP regions.
and relate to advances which have provided fresh 5 Colloids. The importance of the role played by col-
insights into marine processes. The areas in which our loids in trace metal cycles has begun to be appreciated
knowledge of oceanic processes have undergone fun- to a greater extent over the past few years, and will be
damental conceptual changes include the following. a field for considerable further expansion.
1 Trace metal speciation.When the first edition was 6 The preservation/destruction of organic matter in
written this topic was still in its relative infancy, but marine sediments. In marine geochemistry, as in all
the field has expanded considerably over the past few scientific disciplines, certain topics are in vogue at
years. In particular, speciation studies have allowed particular times. If, on the basis of fundamental
new theories in trace-metal–biota relationships to be advances, the 1970s and 1980s could be regarded as
established. For example, it has been suggested that having been the ‘trace metal’ decades in ocean
feedback mechanisms between biological and chemi- research, the 1990s and beyond may well come to be
cal systems may be of the utmost importance in the viewed as the ‘organic matter’ decades. Already a
‘high nitrogen, low productivity’ (HNLP) regions of number of new theories have emerged on the factors
the oceans; with the biology strongly influencing the controlling the preservation of organic matter in
chemical speciation of the bioactive trace metals, and marine sediments. Like all revolutionary theories
the speciation of the metals themselves influencing these have been challenged, but they have opened up
primary production, species composition and trophic exciting avenues which will be further explored in the
structure. future.
2 Carbon dioxide, and its role in world climate The text of Marine Geochemistryhas been modified
change. New data have now become available on the to cover a number of these advances, and to accom-
oceanic carbon dioxide system, particularly on the modate them some material from the first edition has
role of new production in the drawdown of carbon been omitted.
dioxide from the atmosphere, and on the magnitudes In addition to the acknowledgements made in the
of the carbon dioxide fluxes associated with the Preface to the first edition, I would like to express my
major oceanic source/sink regions. personal thanks to my colleagues Dr H. Leach and Dr
viii