Physical Geology : Earth Revealed , Seventh Edition

Cover Page
......Page 1
Title Page
......Page 4
Copyright Page
......Page 5
BRIEF CONTENTS......Page 6
Preface
......Page 14
CONTENTS......Page 7
1 Introducing Geology, the Essentials of Plate Tectonics, and OtherImportant Concepts......Page 26
Supplying Things We Need......Page 27
Avoiding Geologic Hazards......Page 28
Understanding Our Surroundings......Page 32
Earth Systems......Page 33
An Overview of Physical Geology—Important Concepts......Page 34
The Theory of Plate Tectonics......Page 36
Divergent Boundaries......Page 37
Convergent Boundaries......Page 38
Transform Boundaries......Page 42
Surficial Processes: The Earth’s External Heat Engine......Page 44
Geologic Time......Page 47
SUMMARY......Page 48
2 Earth’s Interior and Geophysical Properties......Page 52
Evidence from Seismic Waves......Page 53
The Crust......Page 56
The Mantle......Page 57
The Core......Page 59
Isostasy......Page 63
Gravity Measurements......Page 65
Magnetic Reversals......Page 67
Magnetic Anomalies......Page 70
Geothermal Gradient......Page 71
Heat Flow......Page 72
SUMMARY......Page 73
3 The Sea Floor 
......Page 78
Methods of Studying the Sea Floor
......Page 79
Continental Shelves and Continental Slopes......Page 81
Submarine Canyons......Page 83
Turbidity Currents......Page 84
Passive Continental Margins......Page 85
Abyssal Plains......Page 86
Oceanic Trenches......Page 87
Geologic Activity on the Ridge......Page 88
Seamounts, Guyots, and Aseismic Ridges......Page 90
Reefs......Page 92
Oceanic Crust and Ophiolites......Page 94
SUMMARY......Page 97
4 Plate Tectonics 
......Page 102
The Early Case for Continental Drift......Page 104
Skepticism about Continental Drift
......Page 106
Paleomagnetism and the Revival of Continental Drift......Page 107
Recent Evidence for Continental Drift......Page 108
Hess’s Driving Force......Page 109
Explanations......Page 110
Marine Magnetic Anomalies......Page 111
Another Test: Fracture Zones and Transform Faults......Page 114
Divergent Plate Boundaries......Page 115
Ocean-Ocean Convergence......Page 120
Ocean-Continent Convergence......Page 122
Continent-Continent Convergence......Page 123
Plate Size......Page 126
What Causes Plate Motions?......Page 127
Mantle Plumes and Hot Spots......Page 129
SUMMARY......Page 133
5 Mountain Belts and the Continental Crust 
......Page 138
Introduction......Page 139
Ages of Mountain Belts and Continents......Page 142
Thickness and Characteristics of Rock Layers......Page 143
Metamorphism and Plutonism......Page 144
Normal Faulting......Page 145
Thickness and Density of Rocks......Page 146
Orogenies and Plate Convergence 1......Page 147
Post-Orogenic Uplift and Block-Faulting......Page 152
Displaced Terranes......Page 156
SUMMARY......Page 158
6 Geologic Structures
......Page 162
Stress and Strain in the Earth’s Lithosphere......Page 163
How Do Rocks Behave When Stressed?......Page 164
Geologic Maps and Field Methods......Page 165
Folds......Page 167
Geometry of Folds......Page 168
Further Description of Folds......Page 170
Joints......Page 172
Faults......Page 174
SUMMARY......Page 182
7 Earthquakes 
......Page 186
Introduction......Page 187
Causes of Earthquakes......Page 189
Seismic Waves......Page 190
Body Waves......Page 191
Determining the Location of an Earthquake......Page 192
Measuring the Size of an Earthquake......Page 195
Location and Size of Earthquakes in the United States......Page 198
Effects of Earthquakes......Page 200
Tsunami......Page 204
Earthquakes and Plate Tectonics......Page 207
Earthquakes at Plate Boundaries......Page 209
Earthquake Prediction and Seismic Risk......Page 212
SUMMARY......Page 217
8 Time and Geology
......Page 222
The Key to the Past......Page 223
Principles Used to Determine Relative Age......Page 224
Unconformities......Page 229
Correlation......Page 231
Numerical Age......Page 234
Isotopic Dating......Page 235
Uses of Isotopic Dating......Page 240
Combining Relative and Numerical Ages......Page 241
Age of the Earth......Page 242
Comprehending Geologic Time......Page 243
SUMMARY......Page 245
9 Atoms, Elements, and Minerals
......Page 250
Introduction......Page 251
Atoms and Elements......Page 253
Ions and Crystalline Structures 
......Page 254
The Silicon-Oxygen Tetrahedron 
......Page 258
Nonsilicate Minerals......Page 260
Variations in Mineral Structures and Compositions......Page 261
Luster......Page 264
Hardness......Page 265
External Crystal Form......Page 266
Cleavage......Page 268
Specific Gravity 
......Page 270
Special Properties......Page 271
The Many Conditions of Mineral Formation......Page 272
SUMMARY......Page 274
10 Volcanism and Extrusive Rocks
......Page 278
Supernatural Beliefs......Page 279
Volcanic Catastrophes......Page 282
Eruptive Violence and Physical Characteristics of Lava......Page 285
Gases......Page 286
Composition......Page 287
Extrusive Textures......Page 288
Types of Volcanoes......Page 290
Shield Volcanoes......Page 291
Composite Volcanoes......Page 294
Volcanic Domes......Page 298
Lava Floods......Page 299
Pillow Basalts......Page 303
SUMMARY......Page 305
11 Igneous Rocks, Intrusive Activity, and the Origin of 
Igneous Rocks......Page 310
The Rock Cycle......Page 311
A Plate Tectonic Example......Page 312
Ingeneous Rocks
......Page 313
Identification of Igneous Rocks......Page 314
Chemistry of Igneous Rocks......Page 317
Shallow Intrusive Structures......Page 320
Intrusives that Crystallize at Depth......Page 321
Abundance and Distribution of Plutonic Rocks
......Page 322
How Magma Forms
......Page 323
Factors that ControlMelting Temperatures......Page 324
Sequence of Crystallizationand Melting......Page 325
Partial Melting......Page 327
Igneous Processes at DivergentBoundaries......Page 328
Intraplate Igneous Activity......Page 329
Igneous Processes at Convergent Boundaries......Page 330
SUMMARY......Page 334
12 Weathering and Soil 
......Page 338
Atmosphere......Page 339
How Weathering Alters Rocks......Page 340
Effects of Weathering......Page 341
Frost Action......Page 342
Other Processes......Page 343
Chemical Weathering......Page 344
Role of Acids 
......Page 345
Solution Weathering......Page 346
Chemical Weathering of Feldspar......Page 347
Chemical Weathering of Other Minerals......Page 348
Factors Affecting Weathering......Page 349
Soil Horizons......Page 350
Residual and Transported Soils......Page 352
Soils and Climate......Page 354
SUMMARY......Page 356
13 Mass Wasting 
......Page 360
Introduction to Mass Wasting
......Page 361
Type of Movement......Page 362
Gravity......Page 365
Water......Page 366
Creep......Page 367
Flow......Page 369
Rockfalls and Rockslides......Page 373
Underwater Landslides......Page 376
Preventing Mass Wasting of Soil......Page 377
Preventing Rockfalls and Rockslides on Highways......Page 379
SUMMARY......Page 381
14 Sediment and Sedimentary Rocks
......Page 384
Transportation......Page 386
Deposition......Page 387
Lithification......Page 388
Breccia and Conglomerate 
......Page 390
Sandstone......Page 392
The Fine-Grained Rocks......Page 393
Carbonate Rocks......Page 394
Evaporites......Page 398
The Origin of Oil and Gas......Page 399
Sedimentary Structures......Page 400
Fossils......Page 404
Formations......Page 405
Source Area......Page 406
Environment of Deposition......Page 408
Plate Tectonics and Sedimentary Rocks......Page 410
SUMMARY......Page 412
15 Metamorphism, Metamorphic Rocks, and Hydrothermal Rocks
......Page 416
Introduction......Page 417
Factors Controlling the Characteristics of Metamorphic Rocks......Page 418
Temperature......Page 419
Pressure......Page 420
Fluids......Page 421
Nonfoliated Rocks......Page 422
Foliated Rocks......Page 424
Regional Metamorphism......Page 426
Pressure-Temperature Regimes......Page 430
Hydrothermal Processes......Page 432
Hydrothermal Activity at Divergent Plate Boundaries......Page 433
Metasomatism......Page 434
Hydrothermal Rocks and Minerals......Page 435
SUMMARY......Page 437
16 Streams and Floods
......Page 440
Earth Systems—Thehydrologic Cycle......Page 441
Running Water......Page 442
Drainage Patterns......Page 443
Velocity......Page 444
Discharge......Page 446
Stream Erosion......Page 447
Stream Transportation of Sediment......Page 448
Bars......Page 450
Meandering Streams and Point Bars......Page 453
Flood Plains......Page 454
Deltas......Page 456
Alluvial Fans......Page 458
Flash Floods......Page 459
The Great Flood of 1993......Page 463
Downcutting and Base Level......Page 466
The Concept of a Graded Stream......Page 467
Stream Terraces......Page 468
Incised Meanders......Page 470
SUMMARY......Page 472
17 Ground Water
......Page 476
Porosity and Permeability......Page 477
The Water Table......Page 478
The Movement of Ground Water......Page 479
Aquifers......Page 481
Wells......Page 482
Springs and Streams......Page 483
Contamination of Ground Water......Page 486
Caves, Sinkholes, and Karst Topography......Page 490
Other Effects......Page 493
Hot Water Underground......Page 494
Geothermal Energy......Page 495
SUMMARY......Page 496
18 Deserts and Wind Action 
......Page 500
Distribution of Deserts......Page 501
Some
 Characteristics of Deserts......Page 502
Desert Features in the Southwestern United States......Page 505
Wind Erosion and Transportation......Page 509
Wind Deposition......Page 511
SUMMARY......Page 518
19 Glaciers and Glaciation 
......Page 522
Introduction......Page 523
Formation and Growth of Glaciers......Page 524
Movement of Valley Glaciers......Page 527
Movement of Ice Sheets......Page 529
Glacial Erosion......Page 531
Erosional Landscapes Associated with Alpine Glaciation......Page 532
Glacial Deposition......Page 537
Moraines......Page 538
Outwash......Page 541
The Theory of Glacial Ages......Page 542
Direct Effects of Past Glaciation in North America......Page 544
Indirect Effects of Past Glaciation......Page 546
Evidence for Older Glaciation......Page 549
SUMMARY......Page 550
20 Waves, Beaches, and Coasts 
......Page 554
Water Waves......Page 555
Surf......Page 556
Rip Currents......Page 557
Beaches......Page 559
Longshore Drift of Sediment......Page 560
Human Interference with Sand Drift......Page 561
Erosional Coasts......Page 563
Depositional Coasts......Page 565
Drowned Coasts......Page 566
Uplifted Coasts......Page 567
The Biosphere and Coasts......Page 568
SUMMARY......Page 571
21 Geologic Resources 
......Page 574
Energy Resources......Page 575
Coal......Page 576
Petroleum and Natural Gas......Page 579
Heavy Crude and Oil Sands......Page 585
Oil Shale......Page 587
Uranium......Page 588
Geothermal Power......Page 589
Renewable Energy Sources......Page 591
Ores Formed by Igneous Processes......Page 592
Ores Formed by Surface Processes......Page 594
Mining......Page 595
Some Important Metals......Page 596
Construction Materials......Page 599
Other Nonmetallics......Page 600
The Human Perspective......Page 601
SUMMARY......Page 602
22 Earth’s Companions 
......Page 606
The Sun......Page 607
The Solar System......Page 608
The Milky Way and the Universe......Page 609
The Solar Nebula......Page 611
Formation of Atmospheres......Page 613
Portraits of the Planets......Page 614
Description of the Moon......Page 615
Mercury......Page 618
Venus......Page 621
Mars......Page 623
Why Are the Terrestrial Planets So Different?......Page 628
Jupiter......Page 629
Saturn......Page 632
Neptune......Page 633
Pluto......Page 634
Meteorites......Page 635
Comets......Page 636
Giant Meteor Impacts......Page 638
SUMMARY......Page 639
Appendix A Identification of Minerals......Page 641
Appendix B Identification of Rocks......Page 645
Appendix C The Elements Most Significant to Geology......Page 648
Appendix D Periodic Table of Elements......Page 649
Appendix E Selected Conversion Factors......Page 650
Appendix F Rock Symbols......Page 651
Appendix G Commonly Used Prefixes, Suffices, and Roots......Page 652
Glossary......Page 653
Index......Page 665