Paleomagnetism : continents and oceans / Michael W. McElhinny, Phillip L. McFadden.

Format:

Book

Author/Creator:

McElhinny, M. W.

Contributor:

McFadden, Phillip L.

Series:

International geophysics series 0074-6142 ; v. 73.

International geophysics series, 0074-6142 ; v. 73

Language:

English

Subjects (All):

Paleomagnetism.

Physical Description:

xii, 386 pages : illustrations (some color), maps (some color) ; 24 cm.

Place of Publication:

San Diego, Calif. ; London : Academic, [2000]

Summary:

Paleomagnetism is the study of the fossil magnetism in rocks. It has been paramount in determining that the continents have drifted over the surface of the Earth throughout geological time. The fossil magnetism preserved in the ocean floor has demonstrated how continental drift takes place through the process of sea-floor spreading. The methods and techniques used in paleomagnetic studies of continental rocks and of the ocean floor are described and then applied to determining horizontal movements of the Earth's crust over geological time. An up-to-date review of global paleomagnetic data enables 1000 million years of Earth history to be summarized in terms of the drift of the major crustal blocks over the surface of the Earth.

The first edition of McElhinny's book was heralded as a "classic and definitive text". It thoroughly discussed the theory of geomagnetism, the geologic reversals of the Earth's magnetic field, and the shifting of magnetic poles. In the 25 years since the highly successful first edition of Palaeomagnetism and Plate Tectonics (Cambridge, 1973) the many advances in the concepts, methodology, and insights into paleomagnetism warrant this new treatment. This completely updated and revised edition of Paleomagnetism: Continents and Oceans will be a welcome resource for a broad audience of earth scientists as well as laypeople curious about magnetism, paleogeography, geology, and plate tectonics.

Because the book is intended for a wide audience of geologists, geophysicists, and oceanographers. It balances the mathematical and descriptive aspects of each topic.

Contents:

Chapter 1 Geomagnetism and Paleomagnetism

1.1 Geomagnetism 1

1.1.1 Historical 1

1.1.2 Main Features of the Geomagnetic Field 3

1.1.3 Origin of the Main Field 7

1.1.4 Variations of the Dipole Field with Time 12

1.2 Paleomagnetism 14

1.2.1 Early Work in Paleomagnetism 14

1.2.2 Magnetism in Rocks 16

1.2.3 Geocentric Axial Dipole Hypothesis 18

1.2.4 Archeomagnetism 22

1.2.5 Paleointensity over Geological Times 25

1.2.6 Paleosecular Variation 26

Chapter 2 Rock Magnetism

2.1 Basic Principles of Magnetism 31

2.1.1 Magnetic Fields, Remanent and Induced Magnetism 31

2.1.2 Diamagnetism and Paramagnetism 34

2.1.3 Ferro-, Antiferro-, and Ferrimagnetism 35

2.1.4 Hysteresis 37

2.2 Magnetic Minerals in Rocks 38

2.2.1 Mineralogy 38

2.2.2 Titanomagnetites 40

2.2.3 Titanohematites 45

2.2.4 Iron Sulfides and Oxyhydroxides 46

2.3 Physical Theory of Rock Magnetism 48

2.3.1 Magnetic Domains 48

2.3.2 Theory for Single-Domain Grains 51

2.3.3 Magnetic Viscosity 54

2.3.4 Critical Size for Single-Domain Grains 56

2.3.5 Thermoremanent Magnetization 60

2.3.6 Crystallization (or Chemical) Remanent Magnetization 64

2.3.7 Detrital and Post-Depositional Remanent Magnetization 68

2.3.8 Viscous and Thermoviscous Remanent Magnetization 71

2.3.9 Stress Effects and Anisotropy 74

Chapter 3 Methods and Techniques

3.1 Sampling and Measurement 79

3.1.1 Sample Collection in the Field 79

3.1.2 Sample Measurement 82

3.2 Statistical Methods 84

3.2.1 Some Statistical Concepts 84

3.2.2 The Fisher Distribution 87

3.2.3 Statistical Tests 91

3.2.4 Calculating Paleomagnetic Poles and Their Errors 98

3.2.5 Other Statistical Distributions 99

3.3 Field Tests for Stability 100

3.3.1 Constraining the Age of Magnetization 100

3.3.2 The Fold Test 101

3.3.3 Conglomerate Test 108

3.3.4 Baked Contact Test 109

3.3.5 Unconformity Test 111

3.3.6 Consistency and Reversals Tests 112

3.4 Laboratory Methods and Applications 114

3.4.1 Progressive Stepwise Demagnetization 114

3.4.2 Presentation of Demagnetization Data 119

3.4.3 Principal Component Analysis 124

3.4.4 Analysis of Remagnetization Circles 125

3.5 Identification of Magnetic Minerals and Grain Sizes 127

3.5.1 Curie Temperatures 127

3.5.2 Isothermal Remanent Magnetization 128

3.5.3 The Lowrie-Fuller Test 131

3.5.4 Hysteresis and Magnetic Grain Sizes 133

3.5.5 Low-Temperature Measurements 135

Chapter 4 Magnetic Field Reversals

4.1 Evidence for Field Reversal 137

4.1.1 Background and Definition 137

4.1.2 Self-Reversal in Rocks 139

4.1.3 Evidence for Field Reversal 141

4.2 The Geomagnetic Polarity Time Scale 143

4.2.1 Polarity Dating of Lava Flows 0-6 Ma 143

4.2.2 Geochronometry of Ocean Sediment Cores 146

4.2.3 Extending the GPTS to 160 Ma 149

4.3 Magnetostratigraphy 154

4.3.1 Terminology in Magnetostratigraphy 154

4.3.2 Methods in Magnetostratigraphy 155

4.3.3 Quality Criteria for Magnetostratigraphy 157

4.3.4 Late Cretaceous-Eocene: The Gubbio Section 158

4.3.5 Late Triassic GPTS 159

4.3.6 Superchrons 162

4.4 Polarity Transitions 164

4.4.1 Recording Polarity Transitions 164

4.4.2 Directional Changes 166

4.4.3 Intensity Changes 171

4.4.4 Polarity Transition Duration 172

4.4.5 Geomagnetic Excursions 174

4.5 Analysis of Reversal Sequences 175

4.5.1 Probability Distributions 175

4.5.2 Filtering of the Record 177

4.5.3 Nonstationarity in Reversal Rate 179

4.5.4 Polarity Symmetry and Superchrons 180

Chapter 5 Oceanic Paleomagnetism

5.1 Marine Magnetic Anomalies 183

5.1.1 Sea-Floor Spreading and Plate Tectonics 183

5.1.2 Vine-Matthews Crustal Model 188

5.1.3 Measurement of Marine Magnetic Anomalies 189

5.1.4 Nature of the Magnetic Anomaly Source 191

5.2 Modeling Marine Magnetic Anomalies 195

5.2.1 Factors Affecting the Shape of Anomalies 195

5.2.2 Calculating Magnetic Anomalies 199

5.3 Analyzing Older Magnetic Anomalies 204

5.3.1 The Global Magnetic Anomaly Pattern 204

5.3.2 Magnetic Anomaly Nomenclature 208

5.3.3 The Cretaceous and Jurassic Quiet Zones 209

5.4 Paleomagnetic Poles for Oceanic Plates 212

5.4.1 Skewness of Magnetic Anomalies 212

5.4.2 Magnetization of Seamounts 214

5.4.3 Calculating Mean Pole Positions from Oceanic Data 216

5.5 Evolution of Oceanic Plates 221

5.5.1 The Hotspot Reference Frame 221

5.5.2 Evolution of the Pacific Plate 224

Chapter 6 Continental Paleomagnetism

6.1 Analyzing Continental Data 227

6.2 Data Selection and Reliability Criteria 228

6.2.1 Selecting Data for Paleomagnetic Analysis 228

6.2.2 Reliability Criteria 228

6.2.3 The Global Paleomagnetic Database 230

6.3 Testing the Geocentric Axial Dipole Model 232

6.3.1 The Past 5 Million Years 232

6.3.2 The Past 3000 Million Years 236

6.3.3 Global Paleointensity Variations 239

6.3.4 Paleoclimates and Paleolatitudes 241

6.4 Apparent Polar Wander 245

6.4.1 The Concept of Apparent Polar Wander 245

6.4.2 Determining Apparent Polar Wander Paths 246

6.4.3 Magnetic Blocking Temperatures and Isotopic Ages 249

6.5 Phanerozoic APWPs for the Major Blocks 251

6.5.1 Selection and Grouping of Data 251

6.5.2 North America and Europe 252

6.5.3 Asia 261

6.5.4 The Gondwana Continents 269

Chapter 7 Paleomagnetism and Plate Tectonics

7.1 Plate Motions and Paleomagnetic Poles 281

7.1.1 Combining Euler and Paleomagnetic Poles 281

7.1.2 Making Reconstructions from Paleomagnetism 287

7.2 Phanerozoic Supercontinents 289

7.2.1 Laurussia 289

7.2.2 Paleo-Asia 291

7.2.3 Gondwana 295

7.2.4 Pangea 298

7.2.5 Paleogeography: 300 Ma to the present 301

7.3 Displaced Terranes 303

7.3.1 Western North America 303

7.3.2 The East and West Avalon Terranes 306

7.3.3 Armorica 308

7.3.4 The Western Mediterranean 310

7.3.5 South and East Asia 312

7.4 Rodinia and the Precambrian 315

7.4.1 Rodinia 315

7.4.2 Paleomagnetism and Rodinia 317

7.4.3 Earth History: Ma to the Present 321

7.4.4 Precambrian Cratons 323

7.5 Non-Plate Tectonic Hypotheses 325

7.5.1 True Polar Wander 325

7.5.2 An Expanding Earth? 330.

Notes:

Includes bibliographical references (pages 333-376) and index.

ISBN:

0124833551

OCLC:

42622200