Essentials of geology

Cover......Page 1
Title......Page 2
Copyright......Page 3
Contents......Page 7
Preface......Page 16
1 An Introduction to Geology......Page 21
  Physical and Historical Geology......Page 23
  Geology, People, and the Environment......Page 24
  Catastrophism......Page 25
  Geology Today......Page 26
  The Magnitude of Geologic Time......Page 27
 1.3 The Nature of Scientific Inquiry......Page 28
  Theory......Page 29
  Plate Tectonics and Scientific Inquiry......Page 30
  Hydrosphere......Page 31
  Atmosphere......Page 32
  Geosphere......Page 33
  Earth System Science......Page 34
  The Earth System......Page 35
  Origin of Planet Earth......Page 36
  Formation of Earth’s Layered Structure......Page 37
  Earth’s Mantle......Page 38
  The Basic Cycle......Page 40
  Alternative Paths......Page 41
 1.9 The Face of Earth......Page 43
  Major Features of the Continents......Page 45
  Major Features of the Ocean Floor......Page 46
  Concepts in Review......Page 47
  Give It Some Thought......Page 50
2 Plate Tectonics: A Scientific Revolution Unfolds......Page 51
 2.1 From Continental Drift to Plate Tectonics......Page 53
  Evidence: The Continental Jigsaw Puzzle......Page 54
  Evidence: Rock Types and Geologic Features......Page 55
  Evidence: Ancient Climates......Page 56
  Rejection of the Drift Hypothesis......Page 57
 2.4 The Theory of Plate Tectonics......Page 58
  Plate Boundaries......Page 59
  Oceanic Ridges and Seafloor Spreading......Page 61
  Continental Rifting......Page 62
 2.6 Convergent Plate Boundaries and Subduction......Page 63
  Oceanic–Continental Convergence......Page 64
  Oceanic–Oceanic Convergence......Page 65
  Continental–Continental Convergence......Page 66
 2.7 Transform Plate Boundaries......Page 67
 2.8 How Do Plates and Plate Boundaries Change?......Page 69
  Plate Tectonics in the Future......Page 70
  Evidence: Ocean Drilling......Page 71
  Evidence: Mantle Plumes and Hot Spots......Page 72
  Evidence: Paleomagnetism......Page 73
  Geologic Evidence for Plate Motion......Page 76
  Measuring Plate Motion from Space......Page 77
  Forces That Drive Plate Motion......Page 78
  Models of Plate–Mantle Convection......Page 79
  Concepts in Review......Page 80
  Give It Some Thought......Page 83
3 Matter and Minerals......Page 85
  Defining a Mineral......Page 87
  What Is a Rock?......Page 88
  Elements: Defined by Their Number of Protons......Page 89
  Ionic Bonds: Electrons Transferred......Page 91
  Metallic Bonds: Electrons Free to Move......Page 92
  Optical Properties......Page 93
  Mineral Strength......Page 94
  Other Properties of Minerals......Page 96
  Silicate Versus Nonsilicate Minerals......Page 97
  Silicate Structures......Page 98
  Joining Silicate Structures......Page 99
  The Light Silicates......Page 100
  The Dark Silicates......Page 102
 3.8 Important Nonsilicate Minerals......Page 103
  Mineral Resources and Ore Deposits......Page 106
  Concepts in Review:......Page 108
  Give It Some Thought......Page 111
4 Igneous Rocks and Intrusive Activity......Page 113
  The Nature of Magma......Page 115
  Igneous Processes......Page 116
  Granitic (Felsic) Versus Basaltic (Mafic) Compositions......Page 117
  Silica Content as an Indicator of Composition......Page 118
  Types of Igneous Textures......Page 119
  Granitic (Felsic) Igneous Rocks......Page 122
  Pyroclastic Rocks......Page 125
  Generating Magma from Solid Rock......Page 126
  Bowen’s Reaction Series and the Composition of Igneous Rocks......Page 128
  Magmatic Differentiation and Crystal Settling......Page 129
  Assimilation and Magma Mixing......Page 130
  Formation of Andesitic and Granitic Magmas......Page 131
  Nature of Intrusive Bodies......Page 132
  Tabular Intrusive Bodies: Dikes and Sills......Page 133
  Massive Intrusive Bodies: Batholiths, Stocks, and Laccoliths......Page 134
  Magmatic Segregation and Ore Deposits......Page 136
  Origin of Diamonds......Page 138
  Concepts in Review......Page 139
  Give It Some Thought......Page 143
5 Volcanoes and Volcanic Hazards......Page 145
 5.1 Mount St. Helens Versus Kilauea......Page 147
  Factors Affecting Viscosity......Page 148
  Quiescent Versus Explosive Eruptions......Page 149
  Lava Flows......Page 150
  Pyroclastic Materials......Page 152
 5.4 Anatomy of a Volcano......Page 154
  Mauna Loa: Earth’s Largest Shield Volcano......Page 155
  Kilauea, Hawaii: Eruption of a Shield Volcano......Page 156
 5.6 Cinder Cones......Page 157
  Parícutin: Life of a Garden-Variety Cinder Cone......Page 158
 5.7 Composite Volcanoes......Page 159
  Pyroclastic Flow: A Deadly Force of Nature......Page 160
  Lahars: Mudflows on Active and Inactive Cones......Page 161
  Other Volcanic Hazards......Page 162
  Calderas......Page 164
  Fissure Eruptions and Basalt Plateaus......Page 166
  Volcanic Necks and Pipes......Page 167
 5.10 Plate Tectonics and Volcanic Activity......Page 169
  Volcanism at Divergent Plate Boundaries......Page 170
  Intraplate Volcanism......Page 173
  Concepts in Review......Page 174
  Give It Some Thought......Page 177
6 Weathering and Soils......Page 179
 6.1 Weathering......Page 181
  Frost Wedging......Page 182
  Salt Crystal Growth......Page 183
  Biological Activity......Page 184
  How Granite Weathers......Page 185
  Spheroidal Weathering......Page 186
  Rock Characteristics......Page 187
  Differential Weathering......Page 188
  What Is Soil?......Page 189
  Climate......Page 190
  Topography......Page 191
 6.7 The Soil Profile......Page 192
 6.8 Classifying Soils......Page 193
  Clearing the Tropical Rain Forest—A Case Study of Human Impact on Soil......Page 195
  Soil Erosion: Losing a Vital Resource......Page 196
  Concepts in Review......Page 199
  Give It Some Thought......Page 202
7 Sedimentary Rocks......Page 203
 7.1 The Importance of Sedimentary Rocks......Page 205
 7.2 Origins of Sedimentary Rock......Page 206
 7.3 Detrital Sedimentary Rocks......Page 207
  Shale......Page 208
  Sandstone......Page 209
  Limestone......Page 211
  Dolostone......Page 213
  Chert......Page 214
 7.5 Coal: An Organic Sedimentary Rock......Page 215
  Lithification......Page 217
 7.7 Classification of Sedimentary Rocks......Page 218
  Importance of Sedimentary Environments......Page 219
  Sedimentary Facies......Page 220
  Sedimentary Structures......Page 223
  Nonmetallic Mineral Resources......Page 225
  Energy Resources......Page 226
 7.10 The Carbon Cycle and Sedimentary Rocks......Page 228
  Concepts in Review......Page 230
  Give It Some Thought......Page 233
8 Metamorphism and Metamorphic Rocks......Page 235
 8.1 What Is Metamorphism?......Page 237
  Heat as a Metamorphic Agent......Page 238
  Confining Pressure......Page 239
  Chemically Active Fluids......Page 240
  Foliation......Page 241
  Foliated Textures......Page 242
  Other Metamorphic Textures......Page 243
  Foliated Metamorphic Rocks......Page 244
  Nonfoliated Metamorphic Rocks......Page 246
  Contact or Thermal Metamorphism......Page 247
  Hydrothermal Metamorphism......Page 248
  Regional Metamorphism......Page 249
  Other Metamorphic Environments......Page 250
  Index Minerals and Metamorphic Grade......Page 251
  Concepts in Review......Page 253
  Give It Some Thought......Page 255
9 Earthquakes and Earth’s Interior......Page 257
 9.1 What Is an Earthquake?......Page 259
  Discovering the Causes of Earthquakes......Page 260
  Aftershocks and Foreshocks......Page 261
  Faults and Large Earthquakes......Page 262
  Instruments That Record Earthquakes......Page 263
  Seismic Waves......Page 264
 9.3 Locating the Source of an Earthquake......Page 265
  Magnitude Scales......Page 267
  Destruction from Seismic Vibrations......Page 270
  Fire......Page 271
  What Is a Tsunami?......Page 272
  Earthquakes Associated with Plate boundaries......Page 274
  Damaging Earthquakes East of the Rockies......Page 275
  Short-Range Predictions......Page 276
  Long-Range Forecasts......Page 278
 9.8 Earth’s Interior......Page 279
  Probing Earth’s Interior: “Seeing” Seismic Waves......Page 280
  Mantle......Page 281
  Concepts in Review......Page 282
  Give It Some Thought......Page 285
10 Origin and Evolution of the Ocean Floor......Page 287
  Mapping the Seafloor......Page 289
  Passive Continental Margins......Page 291
  Active Continental Margins......Page 292
  Deep-Ocean Trenches......Page 293
  Volcanic Structures on the Ocean Floor......Page 294
  Explaining Coral Atolls—Darwin’s Hypothesis......Page 295
 10.4 Anatomy of the Oceanic Ridge......Page 296
 10.5 Oceanic Ridges and Seafloor Spreading......Page 297
  Spreading Rates and Ridge Topography......Page 298
 10.6 The Nature of Oceanic Crust......Page 299
  Interactions Between Seawater and Oceanic Crust......Page 300
  Evolution of an Ocean Basin......Page 301
  Why Oceanic Lithosphere Subducts......Page 303
  Subducting Plates: The Demise of Ocean Basins......Page 304
  Concepts In Review......Page 305
  Give It Some Thought......Page 308
11 Crustal Deformation and Mountain Building......Page 309
 11.1 Crustal Deformation......Page 311
  Types of Deformation......Page 312
  Factors That Affect Rock Strength......Page 313
  Anticlines and Synclines......Page 314
  Domes and Basins......Page 315
  Monoclines......Page 316
 11.3 Faults and Joints: Rock Structures Formed by Brittle Deformation......Page 317
  Dip-Slip Faults......Page 318
  Strike-Slip Faults......Page 319
  Joints......Page 320
 11.4 Mountain Building......Page 322
  Andean-Type Mountain Building......Page 323
  Sierra Nevada, Coast Ranges, and Great Valley......Page 324
  Cordilleran-Type Mountain Building......Page 325
  The Himalayas......Page 327
  The Appalachians......Page 328
  The Principle of Isostasy......Page 331
  How High Is Too High?......Page 332
  Concepts in Review......Page 333
  Give It Some Thought......Page 335
12 Mass Wasting: The Work of Gravity......Page 337
  Landslides as Geologic Hazards......Page 339
  Slopes Change Through Time......Page 340
  The Role of Water......Page 341
  Removal of Vegetation......Page 342
  Earthquakes as Triggers......Page 343
  The Potential for Landslides......Page 344
  Type of Motion......Page 345
 12.4 Rapid Forms of Mass Wasting......Page 346
  Rockslide......Page 347
  Debris Flow......Page 348
  Earthflow......Page 349
  Creep......Page 350
  The Sensitive Permafrost Landscape......Page 351
  Concepts in Review......Page 352
  Give It Some Thought......Page 355
13 Running Water......Page 357
 13.1 Earth as a System: The Hydrologic Cycle......Page 359
 13.2 Running Water......Page 360
  River Systems......Page 361
  Drainage Patterns......Page 362
  Factors Affecting Flow Velocity......Page 363
  Changes Downstream......Page 365
  Stream Erosion......Page 366
  Transport of Sediment by Streams......Page 367
  Alluvial Channels......Page 369
  Base Level and Graded Streams......Page 371
  Valley Deepening......Page 372
  Incised Meanders and Stream Terraces......Page 373
  Deltas......Page 375
  The Mississippi River Delta......Page 376
  Alluvial Fans......Page 377
  Types of Floods......Page 378
  Flood Control......Page 379
  Concepts in Review......Page 381
  Give It Some Thought......Page 383
14 Groundwater......Page 385
  Geologic Importance of Groundwater......Page 387
  Groundwater: A Basic Resource......Page 388
  The Water Table......Page 389
  Permeability, Aquitards, and Aquifers......Page 392
  A Simple Groundwater Flow System......Page 393
  Different Scales of Movement......Page 394
 14.5 Wells......Page 395
 14.6 Artesian Systems......Page 396
  Hot Springs......Page 398
  Geysers......Page 399
  Mining Groundwater......Page 401
  Subsidence......Page 402
  Saltwater Contamination......Page 403
  Groundwater Contamination......Page 404
  Caverns......Page 405
  Karst Topography......Page 406
  Concepts in Review......Page 409
  Give It Some Thought......Page 411
15 Glaciers and Glaciation......Page 413
 15.1 Glaciers: A Part of Two Basic Cycles......Page 415
  Ice Sheets......Page 416
  Other Types of Glaciers......Page 417
  How Glaciers Move......Page 418
  Observing and Measuring Movement......Page 419
  Budget of a Glacier: Accumulation Versus Wastage......Page 420
  How Glaciers Erode......Page 422
  Landforms Created by Glacial Erosion......Page 423
  Glacial Drift......Page 426
  Moraines, Outwash Plains, and Kettles......Page 427
  Drumlins, Eskers, and Kames......Page 429
  Sea-Level Changes......Page 430
  Changes to Rivers and Valleys......Page 431
  Pluvial Lakes......Page 432
  Development of the Glacial Theory......Page 433
  Causes of Ice Ages......Page 434
  Concepts in Review......Page 437
  Give It Some Thought......Page 439
16 Deserts and Wind......Page 441
  Subtropical Deserts and Steppes......Page 443
  Middle-Latitude Deserts and Steppes......Page 444
 16.2 Geologic Processes in Arid Climates......Page 445
  The Role of Water......Page 446
 16.3 Basin and Range: The Evolution of a Desert Landscape......Page 447
  Transportation of Sediment by Wind......Page 449
  Erosional Features......Page 451
  Sand Deposits......Page 453
  Types of Sand Dunes......Page 454
  Loess (Silt) Deposits......Page 456
  Concepts in Review......Page 457
  Give It Some Thought......Page 458
17 Shorelines......Page 459
  Basic Features......Page 461
  Beaches......Page 462
  Circular Orbital Motion......Page 464
  Waves in the Surf Zone......Page 465
  Sand Movement on the Beach......Page 466
  Depositional Features......Page 469
  The Evolving Shore......Page 470
 17.5 Stabilizing the Shore......Page 472
  Hard Stabilization......Page 473
  Alternatives to Hard Stabilization......Page 474
  Atlantic and Gulf Coasts......Page 475
  Pacific Coast......Page 476
  Coastal Classification......Page 477
  Profile of a Hurricane......Page 478
  Hurricane Destruction......Page 480
  Causes of Tides......Page 482
  Tidal Currents......Page 483
  Concepts in Review......Page 484
  Give It Some Thought......Page 487
18 Geologic Time......Page 489
  The Importance of a Time Scale......Page 491
  Principle of Original Horizontality......Page 492
  Inclusions......Page 493
  Unconformities......Page 494
  Applying Relative Dating Principles......Page 496
  Types of Fossils......Page 497
  Conditions Favoring Preservation......Page 498
  Correlation Within Limited Areas......Page 499
  Fossils and Correlation......Page 501
  Radioactivity......Page 502
  Half-Life......Page 503
  Using Various Isotopes......Page 504
  Dating with Carbon-14......Page 505
 18.5 The Geologic Time Scale......Page 506
  Terminology and the Geologic Time Scale......Page 507
 18.6 Determining Numerical Dates for Sedimentary Strata......Page 508
  Concepts in Review......Page 509
  Give It Some Thought......Page 511
19 Earth’s Evolution Through Geologic Time......Page 513
  The Right Planet......Page 515
  Viewing Earth’s History......Page 516
  Earth’s Early Evolution......Page 518
  Oxygen in the Atmosphere......Page 520
  Evolution of the Oceans......Page 521
 19.4 Precambrian History: The Formation of Earth’s Continents......Page 522
  Earth’s First Continents......Page 523
  The Making of North America......Page 524
  Supercontinents of the Precambrian......Page 525
  Paleozoic History......Page 527
  Mesozoic History......Page 528
  Cenozoic History......Page 529
  Origin of Life......Page 531
  Early Paleozoic Life-Forms......Page 533
  The Great Permian Extinction......Page 535
  Reptiles: Dominating the Land, Sea, and Sky......Page 537
  Demise of the Dinosaurs......Page 538
  From Reptiles to Mammals......Page 540
  Humans: Mammals with Large Brains and Bipedal Locomotion......Page 541
  Large Mammals and Extinction......Page 542
  Concepts in Review......Page 543
  Give It Some Thought......Page 545
20 Global Climate Change......Page 547
  Climate–Geology Connections......Page 549
 20.2 Detecting Climate Change......Page 550
  Oxygen Isotope Analysis......Page 551
  Tree Rings—Archives of Environmental History......Page 552
  Other Types of Proxy Data......Page 553
  Composition of the Atmosphere......Page 554
  Extent and Structure of the Atmosphere......Page 555
  Energy from the Sun......Page 557
  Heating the Atmosphere: The Greenhouse Effect......Page 558
 20.5 Natural Causes of Climate Change......Page 559
  Volcanic Activity and Climate Change......Page 560
  Solar Variability and Climate......Page 562
  Rising CO2 Levels......Page 563
  The Atmosphere’s Response......Page 564
  The Role of Trace Gases......Page 565
  Computer Models of Climate: Important yet Imperfect Tools......Page 567
 20.8 How Aerosols Influence Climate......Page 568
  Sea-Level Rise......Page 569
  The Changing Arctic......Page 570
  The Potential for “Surprises”......Page 572
  Concepts in Review......Page 573
  Give It Some Thought......Page 576
Appendix Metric and English Units Compared......Page 577
Glossary......Page 578
 C......Page 587
 F......Page 588
 H......Page 589
 M......Page 590
 P......Page 591
 S......Page 592
 Z......Page 593