Paleomagnetism of Sedimentary Rocks This Book Is Dedicated to My Son, Peter (1989– 2008), to My Daughters, Emily and Alice, and to Anna
Total Page：16
File Type：pdf, Size：1020Kb
Paleomagnetism of Sedimentary Rocks This book is dedicated to my son, Peter (1989– 2008), to my daughters, Emily and Alice, and to Anna. COMPANION WEBSITE: This book has a companion website: www.wiley.com/go/kodama/paleomagnetism with Figures and Tables from the book Paleomagnetism of Sedimentary Rocks Process and Interpretation Kenneth P. Kodama Professor, Department of Earth and Environmental Sciences Lehigh University Bethlehem Pennsylvania, USA A John Wiley & Sons, Ltd., Publication This edition fi rst published 2012 © 2012 by Kenneth P. Kodama. Blackwell Publishing was acquired by John Wiley & Sons in February 2007. Blackwell’s publishing program has been merged with Wiley’s global Scientifi c, Technical and Medical business to form Wiley-Blackwell. Registered offi ce: John Wiley & Sons, Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK Editorial offi ces: 9600 Garsington Road, Oxford, OX4 2DQ, UK The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK 111 River Street, Hoboken, NJ 07030-5774, USA For details of our global editorial offi ces, for customer services and for information about how to apply for permission to reuse the copyright material in this book please see our website at www.wiley.com/wiley-blackwell. The right of the author to be identifi ed as the author of this work has been asserted in accordance with the UK Copyright, Designs and Patents Act 1988. 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, except as permitted by the UK Copyright, Designs and Patents Act 1988, without the prior permission of the publisher. Designations used by companies to distinguish their products are often claimed as trademarks. All brand names and product names used in this book are trade names, service marks, trademarks or registered trademarks of their respective owners. The publisher is not associated with any product or vendor mentioned in this book. This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is sold on the understanding that the publisher is not engaged in rendering professional services. If professional advice or other expert assistance is required, the services of a competent professional should be sought. Library of Congress Cataloging-in-Publication Data Kodama, Kenneth P. Paleomagnetism of sediments and sedimentary rocks : process and interpretation / Kenneth P. Kodama. p. cm. Includes bibliographical references and index. ISBN 978-1-4443-3502-6 (cloth) 1. Paleomagnetism. 2. Sediments (Geology) I. Title. QE501.4.P35K64 2013 552'.501538727–dc23 2012011834 A catalogue record for this book is available from the British Library. Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books. Front cover image: “Red Rocks” – original oil painting by Anna Kodama Cover Design by: Steve Thompson Set in 9/11 pt Photina by Toppan Best-set Premedia Limited 1 2012 Contents 1 The Paleomagnetism of Sediments and 7 Tectonic Strain Effects on Remanence: Sedimentary Rocks: Importance Rotation of Remanence and Remagnetization and Reliability, 1 in Orogenic Belts, 81 2 The Magnetization Mechanism of Sediments and 8 Magnetization of Sediments and the Sedimentary Rocks: Depositional Remanent Environment, 94 Magnetization, 16 9 The Magnetization of Sedimentary Rocks: 3 Post-Depositional Remanent Magnetization, 26 Processes and their Interpretation, 124 4 Inclination Shallowing in Sedimentary Rocks: Evidence, Mechanism and Cause, 34 Glossary of Paleomagnetic and Rock Magnetic Acronyms, 136 5 How to Detect and Correct a Compaction-shallowed Inclination, 46 References, 139 6 Post-Depositional Diagenesis and Chemical Index, 154 Remanent Magnetization, 66 Color plate between pages 90 and 91 COMPANION WEBSITE: This book has a companion website: www.wiley.com/go/kodama/paleomagnetism with Figures and Tables from the book Plate 1 (Figure 3.2) Diagram of how de Menocal et al. (1990) and other workers determine the lock-in depth of a paleomagnetic marker such as the Brunhes–Matuayama polarity transition (BMM) or a geomagnetic excursion. Essentially, the depth difference between the paleomagnetic marker and an earlier time marker that doesn’t have a lag in the sediment column (a foram layer, a 10Be-dated layer or a tektite layer) is plotted versus the sediment accumulation rate. Each data point comes from a different core, sampling sediments with different accumulation rates. The y-intercept of the red line is a measure of the lock-in depth of the paleomagnetic marker. Figure redrafted from Earth & Planetary Science Letters, 99, PB de Menocal et al., Depth of post-depositional remanence acquisition in deep-sea sediments: a case study of the Brunhes- Matuyama reversal and oxygen isotope Stage 19.1, 1–13, copyright 1990, with permission from Elsevier. Paleomagnetism of Sedimentary Rocks: Process and Interpretation, First Edition. Kenneth P. Kodama. © 2012 Kenneth P. Kodama. Published 2012 by Blackwell Publishing Ltd. Plate 2 (Figure 3.3) Comparison of the Bermuda Rise (BR, Lund & Keigwin 1994) and Lake St Croix (LSC, Lund & Banerjee 1985) paleosecular variation records as envisioned by Tauxe et al. (2006). The inclination records (on the left) are correlated according to each core’s age model as presented by Tauxe et al. (2006). The offset in absolute inclination is more than likely due to the difference in latitudes between the sites. As Tauxe et al. point out, the major features in the paleosecular variation show no offsets, arguing against a lock-in depth for the Bermuda Rise sediments. However, when declinations are compared for the two records (on the right) using exactly the same correlation, the declination swing to the east in the Bermuda Rise record is decreased in amplitude and increased in wavelength (smoothed) and offset down in the sediment column. This behavior is usually observed for a pDRM lock-in depth, in this case about 8 cm in the Bermuda Rise record. Plate 3 (Figure 4.1) tan If versus tan I0 for single-clay synthetic sediments (kaolinite, illite, montmorillonite) in saline pore water (blue), distilled water (green) and for natural marine sediments (red). The slope of the lines indicates the best-fi t fl attening factor f for each sediment type. The f factors range from 0.68 for distilled pore water to 0.74 for natural sediments, very similar to those for Anson & Kodama’s (1987) experiments. Plate 4 (Figure 4.2) Change in intensity (ΔJ) for single-clay synthetic sediments (top) and natural sediments (bottom) as a function of initial inclination during laboratory compaction. All synthetic sediments include 0.5 mm acicular magnetite and either distilled pore water (top left) or saline pore water (top right). Montmorillonite, illite, kaolinite and clay-rich natural sediments (Muddy Natural Sediment) show a strong relationship between initial inclination and the size of the intensity decrease. Decreased clay content in the natural marine sediment (Silty Marine Sediment) reduces the effect for steep and intermediate inclinations. 40 30 PP 20 LW PL 10 0 Northward transport (˚) -10 20 30 40 50 60 70 80 90 100 Age (Ma) Plate 5 (Figure 5.4) Paleolatitudinal offset of California tectonostratigraphic terranes shown by red circles as a function of age in Ma. Offsets are calculated from the paleomagnetic data of sedimentary rocks for different tectonostratigraphic terranes compared to the predicted paleolatitude for cratonic North America for a particular age. Blue squares show the uncorrected paleolatitudinal offset for the Cretaceous Pigeon Point Formation (PP) and the Cretaceous Ladd and Williams Formation (LW). The blue arrows point to the corresponding anisotropy-corrected paleolatitudinal offsets shown by the blue hexagons. Red square and hexagon are for the Cretaceous Point Loma Formation (PL). In these three cases, the paleomagnetic inclination for these formations was corrected for inclination shallowing with the remanence anisotropy measured for the rocks. (See references for the terranes depicted by the red circles in Butler et al. 1991.) Plate 6 (Figure 5.7) Site mean directions before (left) and after (right) individual sample-by-sample magnetic anisotropy correction of inclination shallowing (Kodama 1997). The mean of the site means (square with 95% confi dence circle) moves from shallower than the expected Paleocene direction for North America, shown by gray hexagon (based on Diehl et al. 1983), to nearly exactly in agreement with it after correction. KP Kodama, A successful rock magnetic technique for correcting paleomagnetic inclination shallowing: Case study of the Nacimiento Formation, New Mexico, Journal of Geophysical Research, 102, B3, 5193–5205, 1997. Figure 14, page 5202. Copyright 1997 American Geophysical Union. Reproduced by kind permission of American Geophysical Union. Plate 7 (Figure 5.8) Red dots show paleopoles based on red beds for the Mesozoic and Paleozoic. Open squares show Van der Voo’s (1990) mean paleopoles for the lower Tertiary (Tl), upper Cretaceous (Ku), upper Jurassic (Ju), lower Jurassic (Jl), upper Triassic (Tru), lower Triassic (Trl), upper Permian (Pu), lower Permian (Pl), upper Carboniferous (Cu), lower Carboniferous (Cl), upper Devonian (Du), lower Devonian (Dl), upper Silurian/lower Devonian (Su/Dl) and middle Ordovician (Om). The more modern APWP of Besse & Courtillot (2002) only extends back to 200 Ma, or between the Tru and Jl mean paleopoles. North America’s APWP for earlier times relies heavily on results from red beds. Plate 8 (Figure 5.10) LIP data in support of the TK03 fi eld model used for the EI inclination correction. Red line is the TK03 model, dashed lines are from Constable & Parker’s (1988) fi eld model while the dotted line is Quidelleur & Courtillot’s (1996) fi eld model. The Parana LIP is Cretaceous (about 120 Ma) and was considered problematic by Tauxe et al. (2008). Keweenawan is 1.1 Ga and is from the Northshore basalts of Lake Superior (Tauxe & Kodama 2009), E is the 30 Ma Ethiopian traps of Rochette et al.