Table Of ContentPRINCIPLES
OF GEODYNAMICS
BY
ADRIAN E. SCHEIDEGGER
PH. D. (TORONTO) i D1PL. PHYS. ETH. (ZURICH)
PROFESSOR OF PETROPHYSICS
UNIVERSITY OF ILLINOIS, URBANA, ILL. (U.S.A.)
SECOND EDITION
WITH 142 FIGURES
SPRINGER-VERLAG BERLIN HEIDELBERG GMBH
1963
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© by Springer·Veriag Berlin Heidelberg 1958 and 1963
Ursprunglich erschienen bei Springer·Veriag OHG., Berlin· Gottingen· Heidelberg 1963
Library of Congress Catalog Card Number A 58·4632
ISBN 978-3-662-12783-4 ISBN 978-3-662-12781-0 (eBook)
DOI 10.1007/978-3-662-12781-0
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TO
MY WIFE
Preface
Geodynamics is an old science. Most of the basic theories have been
conceived in principle during the 19th century and not many fundamen
tal ideas have been added since. Some progress has been made in the
following-up of these concepts and, in some instances, in the deter
mination of some important facts about the Earth. Nevertheless, geo
dynamics has been a highly speculative subject for about a hundred
years and it is not likely that this situation will change during the next
hundred. It is also unlikely that many basic new ideas will be added in
that time interval. The reason for this lies in the extreme difficulty of
obtaining really relevant data about the mechanics of the Earth, partly
due to the impossibility of probing into the depths of the Earth by direct
means to any considerable extent and partly due to the fact that the time in
tervals in which" something happens" are ofthe order of millions of years,
which is much too long for any human being to wait and experiment with.
The situation in geodynamics is therefore much akin to that which
existed when the ancient Greek philosophers were speculating about the
possibly atomic structure of matter: there was, at that time, absolutely
no hope to either confirm or to reject the hypothesis. The subsequent
historical developments proved indeed that two thousand years of
technological advances were required before the question could be sett
led. Geodynamics is much in the same position now as the physics of
matter was two millennia ago: the basic ideas that one can think of
have all been thought of, but there seems to be no chance of settling
the fundamental questions for a long time to come.
It seems, therefore, that the time is ripe for an evaluation of the
existing ideas in the light of presently available facts. This, in spite of
the early recognition of the subject, has never been done. All existing
books, monographs and papers (of which there is legion) have been
written to advance one or the other of the hypotheses as the "true" one.
This led, in consequence, to much wishful thinking, to the inadvertant
ignoring of unpleasant facts, and to the straining of others to fit pre
conceived ideas. The writer admits that he has been guilty of the same
offense, falling in with the general trend and type of geodynamic specu
lations. It was only after much thought and disappointment that he
arrived, so to speak, at being an "agnostic" on the subject. It is, how
ever, his conviction that any real advances can only be expected if
one starts with such a frame of mind. Otherwise, too much energy is
needlessly wasted in the zealous promotion of concepts for which there
can realistically be no hope of "proof" in the foreseeable future.
VI Preface
The present book represents, therefore, the writer's notes and ideas
on the principles of geodynamics. It is not a comprehensive literature
survey, but rather a compilation of the most competent presentations
of each one of the,-usually very old-, basically possible hypotheses.
Much of the material has been taken from the writer's own earlier at
tempts at struggling for the" proof" of one or the other of the ideas in
which he was inclined to believe at the time, some of it from similar
attempts of other geophysicists. He has particularly heavily drawn from
those of his earlier articles which appeared in the Canadian Journal of
Physics, in the Transactions of the American Geophysical Union, in
Geofisica Pura e Applicata, in the Journal of the Alberta Society of
Petroleum Geologists, in the New Scientist, in the Journal of Geology
(published by the University of Chicago Press), in Canadian Oil and Gas
Industries and in the Bulletin of the Geological Society of America.
Permission to do this has kindly been granted by the editors of the
journals in question and this is here gratefully acknowledged.
The first two chapters of the book give a brief summary of the
physical facts about the Earth as far as they are known, the third puts
together the principles of the theory of deformation of continuous matter
which is the basic mechanical background of geodynamics, and the rest
represents a synoptic view of the subject, much in the same way as one
might present a synoptic view of the world's philosophies, without tak
ing sides for one or the other.
The present edition is already the second edition of the book; in it,
numerous revisions were made. Naturally, the writer is most pleased
by the ready acceptance which quantitative methods have found in the
Earth Sciences. Between the first and second editions of this book, the
writer had an opportunity to write his "Theoretical Geomorphology" and
it is hoped that the two books together form a reasonably coherent
presentation of theoretical quantitative geology.
The writer is indebted to many colleagues and friends for helpful
discussions and stimulating criticism. It was Dr. J. Tuzo WILSON in
Toronto who started him off on the subject of theoretical geophysics in
the first place. Many of the ideas presented here, especially those on the
physiography of the Earth, can therefore be backtraced to Dr. WILSON'S
stimulating influence. The writer owes much to Dr. J. A. JACOBS, of
the University of British Columbia in Vancouver, for the discussion of
mathematical matters, and especially to Dr. EGON OROWAN of the
Massachusetts Institute of Technology whose influence on the writer's
conception of fracture and failure has been great. As usual, the Springer
Verlag has been most efficient in producing the present book and has
always been willing to accede to the writer's numerous requests.
Urbana, Illinois, U.S.A.,
November 3, 1962. A. E. SCHEIDEGGER
Table of Contents
Page
1. Physiographic and Geological Data Regarding the Earth
1.1. Introduction . . . .
1.2. Geological Evolution 3
1.21. The Basic Rock Types 3
1.22. Geological Time Scale 4
1.23. Paleoclimatic Data . . 4
1.3. Geography of Continents and Oceans 10
1.31. Geometrical Arrangement 10
1.32. The Hypsometric Curve. . . . 14
1.33 Comparison of Continents and Oceans 16
1.4. Physiography of Continental Areas 16
1.41. General Features. . . . . . 16
1.42. Mountain Ranges . . . . . 18
1.43. Systems of Mountain Ranges 21
1.44. The Continental Shelf. . . . 25
1.45. Different Views of Orogenesis 25
1.5. Physiography of Oceanic Areas 28
1.51. General Remarks. 28
1.52. Abyssal Plains. . . . . 29
1.53. Mid-Ocean Ridges . . . 30
1.54. Smaller Features in Basins 33
1.6. Physiography of Faults and Folds 34
1.61. Faults . . . . . . . . . . 34
1.62. Folds. . . . . . . . . . . 36
1.63. Patterns of Faults and Folds 37
1.7. Physiography of Some Special Features 38
1.71. Meteor Craters. 38
1. 72. Boudinage 40
1.73. Diapirs .... 40
1.74. Volcanoes. . . 42
1. 7 5. Vertical Displacements 44
II. Geophysical Data Regarding the Earth 47
2.1. The Layering of the Earth .... 47
2.11. Earthquakes and Seismic Waves 47
2.12. The Basic Division of the Earth into Layers 49
2.13. Crustal Studies 50
2.14. The Interior of the Earth . . . . . . .. 52
VIII Table of Contents
Page
2.2. Focal Studies 57
2.21. General Remarks. 57
2.22. Seismicity Studies 57
2.23. Magnitude Studies 60
2.24. Fault Plane Studies 64
2.3. Gravity Data ..... 70
2.31. Gravity and Gravity Anomalies 70
2.32. Distribution of Gravity Anomalies 72
2.4. Underground Stresses . . 75
2.41. General Remarks. . 75
2.42. Direct Measurements 76
2.43. Manifestations in Wells 78
2.44. Manifestations of Ground Stresses in Mine Shafts. 81
2.45. Surface Problems 83
2.46. Seismological Implications. . . . 83
2.47. Geological Manifestations . . . . 86
2.48. Stresses and Large-Scale Tectonics 88
2.5. Data from Age Determinations .... 89
2.51. Principles . . . . . . . . . . . 89
2.52. An Extended Geological Time Scale 90
2.6. Thermal Data 93
2.61. Surface Heat Flow Measurements 93
2.62. Temperature in the Earth's Interior 95
2.63. Thermal History of the Earth 96
2.7. Electromagnetic Effects . . . . 98
2.71. The Earth's Magnetic Field 98
2.72. Paleomagnetism . . 99
2.73. Magnetic Anomalies 101
2.74. Telluric Currents 101
2.8. Geochemical Data. . . . 102
2.81. Geochemistry of the Interior of the Earth. 102
2.82. Geochemistry of the Crust 103
III. The Mechanics of Deformation ... 106
3.1. Finite Strain in Rheological Bodies 106
3.11. The Physics of Deformation . 106
3.12. The Structure of a Finite Strain Theory 107
3.13. The Possible Schemes of Dynamics .. 113
3.14. Additional Stress and Strain ..... 114
3.15. Finite Strain in Tectonic Deformations 115
3.2. Elasticity and Plasticity . . . . . . 117
3.21. Infinitesimal Elasticity Theory. 117
3.22. Dislocations . . . . . . . . 123
3.23. Plasticity . . . . . . . . . 124
3.3. Hydrodynamics of Viscous Fluids . 128
3.31. Fluids Kinematics . . . . . 128
3.32. Dynamics of Viscous Fluids . 129
3.33. Thermohydrodynamics of Viscous Fluids 130
Table of Contents IX
Page
3.4. Other Types of Rheological Behavior 132
3.41. Principles . . . 132
3.42. Maxwell Liquid . . . . . . . 132
3.43. Kelvin Solid. . . . . . . . . 133
3.44. Heat Convection in General Rheology 135
3.5. Discontinuous Displacements. . 137
3.51. The Physics of Fracture. . 137
3.52. Phenomenological Theories 138
3.53. Microscopic Theories . . . 142
3.54. Analytical Attempts . . . 146
3.6. Rheology of the Earth: The Basic Problem of Geodynamics 147
3.61. General Considerations . . . . . 147
3.62. Stresses of Short Duration 149
3.63. Stresses of Intermediate Duration 152
3.64. Stresses of Long Duration. 157
3.65. Summary ....... 160
IV. Effects of the Rotation of the Earth 162
4.1. The Figure of the Earth . . . . 162
4.11. The Ellipticity of the Earth 162
4.12. Theory of the Equilibrium Figure of the Earth. 163
4.2. The Polf1uchtkraft 166
4.21. Concept of the Polf1uchtkraft 166
4.22. ERTEL'S Theory . . . . . . 167
4.23. Criticisms . . . . . . . . . 170
4.3. The Question of Stability of the Earth's Axis of Rotation 171
4.31. The Problem ........... . 171
4.32. Effects of Circulations on a Rigid Earth 171
4.33. Polar Wandering in a Yielding Earth. 173
4.4. Other Effects of the Earth's Rotation 180
4.41. Tidal Forces 180
4.42. Coriolis Force 181
V. Continents and Oceans 182
5.1. Primeval History of the Earth 182
5.11. The Problem of Continents and Oceans 182
5.12. The Origin of the Earth ..... . 182
5.13. The Earth's Early Thermal History 185
5.14. The Birth of the Moon ..... . 188
5.2. Evolution and Growth of Primeval Continents 190
5.21. The Hypothesis of Laurasia and Gondwanaland 190
5.22. The Notion of Continental Drift 190
5.23. Continental Spreading 191
5.24. Volcanic Growth of Continents 191
5.25. Meteorite Impact Hypothesis . 193
x
Table of Contents
Page
5.3. Primeval Convection 193
5.31. The Formation of Continents by Convection. 193
5.32. Physical Aspects of Convection Currents 195
5.33. Analytical Theory . . . . . . . . . 197
5.34. Possibility of Present-Day Convection 201
5.4. Tetrahedral Shrinkage. 202
5.41. Principles . . . . 202
5.42. Criticism . . . . 203
5.5. Formation of Continents by Expansion 203
5.51. General Principles 203
5.52. Thermal Theories 205
5.53. Chemical Theories 207
5.54. Cosmological Speculations. 207
5.6. Evaluation of Theories of Continents and Oceans 208
VI. Orogenesis . . . . 209
6.1. Fundamentals 209
6.11. General Remarks 209
6.12. The Volumes Involved in Orogenesis 209
6.13. The Hypothesis of Crustal Shortening. 210
6.14. Possible Magmatic Origin of Oceanic Features 214
6.15. Geosynclines 216
6.2. The Contraction Hypothesis 218
6.21. Principles . . . . . . 218
6.22. The Existence of a Level of No Strain 223
6.23. The Thickness of the Earth's Crust and Mountain Building. The
Available Contraction. . . . 226
6.24. The Junctions of Island Arcs 229
6.25 The Extension Factor. . . . 234
6.26. Compatibility with Seismic Data . 236
6.27. Compatibility with Oceanic Features 236
6.3. Continental Drift Theory 237
6.31. Principles . . . . . . . . . . . . 237
6.32. Extension Factor. Transcurrent Faulting 240
6.33. Origin of the Forces Causing Drifting. . 241
6.4. Convection Current Hypothesis of Orogenesis 244
6.41. General Principles . . . . . . . 244
6.42. Steady-State Convection . . . . 245
6.43. Intermittent Convection Currents 248
6.44. Roller Cell Theory . . . . . 251
6.45. Rotation Fields . . . . . . 253
6.5. The Hypothesis of Zonal Rotation 254
6.51. Principles . . . . . . . . . 254
6.52. The Origin of the Atlantic Ocean. 255
6.53. Persistence of Zonal Rotation .. 256
Table of Contents XI
Page
6.6. Undation Theory . . . . . . . . . 258
6.61. Principles . . . . . . . . . . 258
6.62. Forces in the Undation Theory 260
6.63. Gravity Tectonics . . . . . . 265
6.64. DALLMus' Secondary Orogenesis 267
6.65. Serpentinization . . . . . . . 270
6.66. Evaluation of the Undation Theory 270
6.7. Expansion Hypothesis of Orogenesis 270
6.71. Principal Outlines . . . . . . 270
6.72. MATSCHINSKI'S Buckling Theory 272
6.73. Expansion by Rock Metamorphism. 272
6.8. Orogenesis and Polar Wandering 273
6.81. The Problem 273
6.82. General Theory ... 275
6.83. The Elastic Model .. 278
6.84. Model of a Weak Earth 280
6.85. Tectonic Significance 284
6.9. Conclusion . . . . . . . . 287
6.91. General Remarks 287
6.92. Orogenesis and Rotation of the Earth 287
6.93. Cosmological Speculations. . . . . 288
6.94. Evaluation of Theories of Orogenesis 289
VII. Dynamics of Faulting and Folding 292
7.1. Dynamics of Faulting . . 292
7.11. Principles . . . . . 292
7.12. ANDERSON'S Theory 292
7.13. Analytical Theories. 296
7.14. The Role of Pore Pressure. 297
7.15. Jointing 297
7.2. Theory of Earthquakes 297
7.21. Requirements of a Theory of Earthquakes 297
7.22. Mechanisms of Stress Creation. 298
7.23. Models of Earthquake Foci . . . 301
7.24. Friction at an Earthquake Fault. 306
7.25. Fracture Theories of Earthquakes 308
7.3. Analytical Theories of Folding 310
7.31. The Problem of Folding. 310
7.32. Buckling . . . . . . . 311
7.33. Theories Assuming Infinitely Flexible Strata 312
7.34. General Rheology ...... . 315
7.4. Model Experiments of Faults and Folds 315
7.41. Theory of Scale Models 315
7.42. Faults 317
7.43. Folds. . . . . . . . 318
