Tabs for Contents, notes, highlights

Hide Contents, Notes, and Highlights

Search TermsShow Hide

« Back to eTextbook

Copyright, iv
About the Authors, v
About Our Sustainability Initiatives, vi
Preface, xxxi
Why Study Earth?, 2
Chapter 1. Why Study Earth?, 2
Why Study Geology?, 2
In the Field, 4
1.1. What Is Geology?, 4
Geologists Work in Many Fields of Study, 5
The Importance of Time in Geology, 6
Putting It Together—What Is Geology?, 7
1.2. Why Study Geology?, 7
Geologists Study Earth Out of Curiosity, 7
Geologists Study Earth to Find Essential Resources, 7
Geologists Study Earth to Reduce Hazards, 8
Putting It Together—Why Study Geology?, 8
1.3. How Do We Know . . . How to Study Earth?, 8
Understanding Geologic Science, 8
Scientific Method, 8
Applying the Scientific Method in Geology, 10
Understanding the Big Picture, 10
Insights, 11
Putting It Together—How Do We Know . . . How to Study Earth?, 11
1.4. What Is the Principle of Uniformitarianism?, 11
Putting It Together—What Is the Principle of Uniformitarianism?, 12
1.5. What Is the Theory of Plate Tectonics?, 12
The Interior of Earth, 12
Tectonic Plates, 13
Types of Plate Boundaries, 13
Hot Spots, 13
Anticipating the Evidence for Plate Tectonics, 15
Putting It Together—What Is the Theory of Plate Tectonics?, 15
1.6. How Does the Concept of Work Apply to Earth?, 15
Work Requires Energy, 15
Heat Drives Geologic Processes, 15
How Heat Causes Motion, 16
Landscapes Have Potential Energy, 17
Putting It Together—How Does the Concept of Work Apply to Earth?, 18
Where Are You and Where Are You Going?, 19
Active Art, 19
Confirm Your Knowledge, 19
Confirm Your Understanding, 19
Part I. Earth Materials: Classification, Origin, Uses, 20
Chapter 2. Minerals: The Building Blocks of the Planet, 20
Why Study Minerals?, 20
In the Field, 22
2.1. What Are the Properties of Minerals?, 22
Minerals Have Characteristic Density, 22
Minerals Have Characteristic Hardness, 22
Some Minerals Have Characteristic Cleavage, 24
Mineral Color and Shape Can Vary, 25
Putting It Together—What Are the Properties of Minerals?, 26
2.2. What Makes Up Minerals?, 26
Extension Module 2.1 Basics of an Atom, 26
Putting It Together—What Makes Up Minerals?, 26
2.3. How Do Elements Combine to Make Minerals?, 26
Chemical Bonds Form Mineral Compounds, 26
Bonds Break when Minerals Dissolve, 28
The Internal Structure of Minerals, 28
Putting It Together—How Do Elements Combine to Make Minerals?, 30
2.4. How Do We Know . . . The Atomic Structure of Minerals?, 30
Understand the Tool, 30
Visualize the Result, 31
Insights, 32
Putting It Together—How Do We Know . . . The Atomic Structure of Minerals?, 32
2.5. What Is a Mineral?, 32
Definition of a Mineral, 32
Putting It Together—What Is a Mineral?, 32
2.6. What Determines the Physical Properties of Minerals?, 32
Composition Commonly Determines Color, 32
Atomic Structure Determines Most Physical Properties, 33
Putting It Together—What Determines the Physical Properties of Minerals?, 34
2.7. Which Minerals Are Most Important?, 35
Silicate Minerals Are the Primary Rock-Forming Minerals in the Crust, 35
Extension Module 2.2 Silicate Mineral Structures, 35
Nonsilicate Minerals Also Are Important, 38
Putting It Together—Which Minerals Are Most Important?, 39
Extension Module 2.3 Gemstones, 39
Where Are You and Where Are You Going?, 40
Extension Modules, 40
Confirm Your Knowledge, 40
Confirm Your Understanding, 41
Chapter 3. Rocks and Rock-Forming Processes, 42
Why Study Rocks?, 42
In the Field, 44
3.1. How and Where Do Rocks Form?, 44
Observations on a Beach, 44
Observations at a Spring, 46
Observations at a Volcano, 46
Putting It Together—How and Where Do Rocks Form?, 47
3.2. How Do We Classify Rocks?, 48
Which Is More Important: Where Rocks Form or How They Form?, 48
The Three Rock Classes, 48
Sedimentary Rocks, 48
Igneous Rocks, 49
Metamorphic Rocks, 49
Putting It Together—How Do We Classify Rocks?, 51
3.3. How Do We Know . . . How to Determine Rock Origins?, 51
Picture the Problem, 51
The Neptunist View, 51
The Vulcanist View, 52
Analyze the Problem, 53
Insights, 53
Putting It Together—How Do We Know . . . How to Determine Rock Origins?, 54
3.4. How Are the Rock Classes Related to One Another?, 54
Putting It Together—How Are the Rock Classes Related to One Another?, 55
Where Are You and Where Are You Going?, 55
Confirm Your Knowledge, 55
Confirm Your Understanding, 55
Chapter 4. The Formation of Magma and Igneous Rocks, 56
Why Study Igneous Rocks?, 56
In the Field, 58
4.1. What Are Igneous Processes?, 58
Putting It Together—What Are Igneous Processes?, 59
4.2. How Are Igneous Rocks Classified?, 59
The First Component in Classification: Composition, 60
The Second Component in Classification: Texture, 62
Naming Igneous Rocks: Composition + Texture, 62
Igneous Rocks Provide Essential Economic Resources, 63
Putting It Together—How Are Igneous Rocks Classified?, 63
4.3. Where Do Igneous Rocks Appear in a Landscape?, 63
Plutonic Rocks in the Landscape, 64
Volcanic Rocks in the Landscape, 65
Types of Volcanoes, 66
Caldera Formation, 68
Putting It Together—Where Do Igneous Rocks Appear in a Landscape?, 69
4.4. How and Why Do Rocks Melt?, 69
How Rocks Melt—Melting Temperature, 69
How Magma Composition Affects Rock Melting, 70
Why Rocks Melt, 70
Extension Module 4.1 Bowen’s Reaction Series, 71
Putting It Together—How and Why Do Rocks Melt?, 71
4.5. How Do We Know . . . How Magma Is Made?, 72
Picture the Problem, 72
Understand the Method, 72
Evaluate the Results, 72
Insights, 73
Putting It Together—How Do We Know . . . How Magma Is Made?, 73
4.6. How Does Magma Generation Relate to Plate Tectonics?, 73
Decompression: Melting at Divergent Plate Boundaries and Hot Spots, 73
Adding Water: Melting at Convergent Plate Boundaries, 73
Putting It Together—How Does Magma Generation Relate to Plate Tectonics?, 74
4.7. What Makes Igneous Rock Compositions So Diverse?, 74
The Melting of Different Rocks, 74
Magma Mixing, 74
Magma Assimilation, 74
Deriving One Magma Composition from Another, 75
Putting It Together—What Makes Igneous Rock Compositions So Diverse?, 76
4.8. Why Are There Different Types of Volcanoes and Volcanic Eruptions?, 76
The First Clue: Gas Content, 76
The Second Clue: Viscosity, 77
Putting It Together—Why Are There Different Types of Volcanoes and Volcanic Eruptions?, 77
4.9. What Hazards Do Volcanoes Present?, 77
The Hazards of Pyroclastic Flows, 77
The Hazards of Lahars, 78
The Hazards of Far-Flung Pumice and Ash, 78
Indirect Volcanic Hazards, 79
Reducing Volcanic Hazards, 79
Extension Module 4.2 Mitigating and Forecasting Volcanic Hazards, 79
Putting It Together—What Hazards Do Volcanoes Present?, 79
4.10. Why Don’t All Magmas Erupt?, 79
How to Make a Pluton, 79
Pluton Crystallization Produces Economic Resources, 80
Putting It Together—Why Don’t All Magmas Erupt?, 81
Where Are You and Where Are You Going?, 82
Active Art, 82
Extension Modules, 82
Confirm Your Knowledge, 83
Confirm Your Understanding, 83
Chapter 5. The Formation of Sediment and Sedimentary Rocks, 84
Why Study Sedimentary Rocks?, 84
In the Field, 86
5.1. How and Why Do Rocks Disintegrate to Form Sediment?, 88
Physical Weathering, 88
Chemical Weathering, 89
Extension Module 5.1 Chemical Reactions and Chemical Equations, 89
Extension Module 5.2 Why Is Seawater Salty?, 90
Extension Module 5.3 Geochemistry of Calcite, 91
What Minerals Survive Weathering?, 91
Putting It Together—How and Why Do Rocks Disintegrate to Form Sediment?, 92
5.2. What Is the Link Between Weathering and Sediment?, 92
Making Clastic Sediment, 92
Making Chemical Sediment, 92
Putting It Together—What Is the Link Between Weathering and Sediment?, 93
5.3. How Does Loose Sediment Become Sedimentary Rock?, 93
The First Step in Forming Sedimentary Rock: Compaction, 93
The Second Step in Forming Sedimentary Rock: Cementation, 93
Putting It Together—How Does Loose Sediment Become Sedimentary Rock?, 94
5.4. How Are Sedimentary Rocks Classified?, 94
Clastic Sedimentary Texture, 95
Clastic Sedimentary Rock Composition, 96
Chemical and Biogenic Sedimentary Rock Composition, 97
Putting It Together—How Are Sedimentary Rocks Classified?, 98
5.5. Why Are Fossils and Fossil Fuels Found in Sedimentary Rocks?, 98
Fossilized Organisms, 98
Fossil Fuels, 98
Extension Module 5.4 When Will We Run Out of Oil?, 99
Putting It Together—Why Are Fossils Found in Sedimentary Rocks?, 100
5.6. How Do Sedimentary Rocks Reveal Ancient Environments?, 101
What Fossils Reveal, 101
What Rock Types Reveal, 101
What Sedimentary Structures Reveal, 102
Evidence of Changing Environments, 104
Putting It Together—How Do Sedimentary Rocks Reveal Ancient Environments?, 105
5.7. How Do We Know . . . How to Interpret Unseen Deep-Ocean Currents?, 105
Picture the Problem, 105
Clues from the Field, 106
Clues from Experiments, 107
Integrating Experiments and Field Descriptions into a Hypothesis, 107
Completing a Uniformitarian Analysis, 107
Insights, 108
Putting It Together—How Do We Know . . . How to Interpret Unseen Deep Ocean Currents?, 108
5.8. How Are Plate Tectonics and Sedimentary Rocks Connected?, 109
Sediment Accumulates in Tectonic Basins, 109
Example of Sedimentary Rocks and Plate Tectonics, 109
Putting It Together—How Are Plate Tectonics and Sedimentary Rocks Connected?, 109
Where Are You and Where Are You Going?, 110
Active Art, 110
Extension Modules, 110
Confirm Your Knowledge, 110
Confirm Your Understanding, 111
Chapter 6. The Formation of Metamorphic Rocks, 112
Why Study Metamorphic Rocks?, 112
In the Field, 114
6.1. What Is Metamorphism?, 114
What Happens During Metamorphism, 115
The Significance of the Original Rock, 115
Putting It Together—What Is Metamorphism?, 116
6.2. What Role Does Temperature Play in Metamorphism?, 116
How Rock Temperature Increases, 116
Heat Drives Away Water and Gases, 117
Mineral Stability, 118
Putting It Together—What Is the Role of Temperature in Metamorphism?, 119
6.3. What Role Does Pressure Play in Metamorphism?, 119
Changes in Mineral Stability, 120
Recrystallization of Minerals into New Sizes and Shapes, 120
Foliation: How Rock Textures Record Strain and Recrystallization, 120
Putting It Together—What Is the Role of Pressure in Metamorphism?, 122
6.4. What Role Does Fluid Play in Metamorphism?, 122
Adding Fluid and Gas During Metamorphism, 122
Fluid Enhances Metamorphism, 123
The Origin of Fluids, 123
Fluid Changes the Composition of the Rocks, 123
Putting It Together—What Is the Role of Fluid in Metamorphism?, 123
6.5. Why Do Metamorphic Rocks Exist at the Surface?, 123
Putting It Together—Why Do Metamorphic Rocks Exist at the Surface?, 124
6.6. How Do We Know . . . How to Determine the Stability of Minerals?, 125
Picture the Problem, 125
Experimental Setup, 125
Visualize the Results, 126
Insights, 126
Putting It Together—How Do We Know . . . How to Determine the Stability of Minerals?, 127
6.7. How Are the Conditions of Metamorphism Determined?, 127
Using Index Minerals, 127
Putting It Together—How Are the Conditions of Metamorphism Determined?, 127
6.8. How Are Metamorphic Rocks Classified?, 128
Using Composition and Texture to Classify Metamorphic Rocks, 128
Foliated Rocks, 130
Non-Foliated or Weakly Foliated Rocks, 131
Putting It Together—How Are Metamorphic Rocks Classified?, 131
6.9. What Was the Rock Before It Was Metamorphosed?, 131
Metamorphosed Sedimentary Rocks, 131
Metamorphosed Igneous Rocks, 132
Putting It Together—What Was the Rock Before It Was Metamorphosed?, 132
6.10. Where Does Metamorphism Take Place?, 132
Contact Metamorphism, 133
Hydrothermal Metamorphism, 134
Regional Metamorphism, 135
Putting It Together—Where Does Metamorphism Occur?, 137
Extension Module 6.1 Metamorphic Isograds, Zones, and Facies, 137
Where Are You and Where Are You Going?, 138
Active Art, 138
Extension Module, 138
Confirm Your Knowledge, 138
Confirm Your Understanding, 139
Chapter 7. Earth Materials as Time Keepers, 140
Why Study the Ages of Rocks?, 140
In the Field, 142
7.1. How Do We Describe Rock Age?, 142
Putting It Together—How Do We Describe Rock Age?, 143
7.2. How Are Geologic Events Placed in Relative Order?, 143
The Principle of Superposition, 143
The Principle of Original Horizontality, 144
The Principle of Cross-Cutting Relationships, 144
The Principle of Inclusions, 145
Putting It Together—How Are Geologic Events Placed in Relative Order?, 145
7.3. How Do Geologists Determine the Relative Ages of Rocks That Are Found Far Apart?, 146
The Principle of Lateral Continuity, 146
The Principle of Faunal Succession, 146
Putting It Together—How Do Geologists Determine the Relative Ages of Rocks That Are Found Far Apart?, 147
7.4. How Was the Geologic Time Scale Constructed?, 148
Putting It Together—How Was the Geologic Time Scale Constructed?, 149
7.5. How Do You Recognize Gaps in the Rock Record?, 149
Unconformities, 150
Putting It Together—How Do You Recognize Gaps in the Rock Record?, 152
7.6. How Have Scientists Determined the Age of Earth?, 152
Nonscientific Assessments of Earth’s Age, 152
Evidence of an Older Earth, 152
How Long Would It Take for Earth to Cool?, 152
Using the Salty Ocean as a Clock, 153
Putting It Together—How Have Scientists Determined the Age of Earth?, 154
7.7. How Is the Absolute Age of a Rock Determined?, 154
The Significance of Radioactivity to Understanding Earth’s Age, 154
Extension Module 7.1 Radioactivity and Radioactive Decay, 154
Measure the Isotope Abundances, 155
Apply the Rate of Radioactive Decay, 156
Radioactive-Isotope Decay Provides Absolute Ages, 156
Understanding the Geologic Conditions, 157
An Example—Potassium-Argon Dating, 158
Extension Module 7.2 The Mathematics of Radioactive-Isotope Decay, 158
Putting Absolute Ages on the Geologic Time Scale, 158
The Oldest Rocks and the Age of Earth, 158
Extension Module 7.3 Using Geologic Clocks, 160
Putting It Together—How Is the Absolute Age of a Rock Determined?, 161
7.8. How Do We Know . . . How to Determine Half-Lives and Decay Rates?, 161
Understand the Problem, 161
Make the Measurements, 161
Visualize the Results, 161
Insights, 161
Putting It Together—How Do We Know . . . How to Determine Half-Lives and Decay Rates?, 162
7.9. How Do You Reconstruct Geologic History with Rocks?, 162
Putting It Together—How Do You Reconstruct Geologic History with Rocks?, 162
Where Are You and Where Are You Going?, 164
Active Art, 164
Extension Modules, 164
Confirm Your Knowledge, 165
Confirm Your Understanding, 165
Part II. Earth’s Internal Processes, 166
Chapter 8. Journey to the Center of Earth, 166
Why Study Earth’s Interior?, 166
In the Lab, 168
8.1. How Do Geologists Learn About Earth’s Interior?, 170
How Far Can We See into Earth?, 170
What Is the Density of Earth?, 171
Extension Module 8.1 Sizing Up Earth, 172
Putting It Together—How Do Geologists Learn About Earth’s Interior?, 172
8.2. How Do Earthquakes Make Images of Earth’s Interior?, 172
Visualizing Waves, 173
Earthquake Waves, 173
How Can Geologists Detect and Measure Earthquake Waves?, 174
A Simple Experiment for Measuring Seismic Waves, 174
Why Seismic Waves Speed Up, 175
Why Travel-Time Curves Are Discontinuous, 176
Extension Module 8.2 How to Locate an Earthquake, 178
Putting It Together—How Do Earthquakes Make Images of Earth’s Interior?, 180
8.3. How Do We Know . . . How to Determine Velocities of Seismic Waves in Rocks?, 180
Define the Problem, 180
Gather the Data, 180
Evaluate the Results, 180
Insights, 181
Extension Module 8.3 Velocity of Seismic Waves, 182
Putting It Together—How Do We Know . . . How to Determine Velocities of Seismic Waves in Rocks?, 182
8.4. What Composes the Interior of Earth?, 182
The Velocity and Density Structure of Earth, 182
The Crust-Mantle Boundary, 184
The Mantle Low-Velocity Zone, 184
The Mantle Transition Zone, 184
Extension Module 8.4 Mantle Minerals, 185
Changes in the Lowermost Mantle, 185
Core Composition, 185
Extension Module 8.5 Meteorites as Guides to Earth’s Interior, 185
Putting It Together—What Composes the Interior of Earth?, 185
8.5. How Hot Is the Interior of Earth?, 185
Determining the Geothermal Gradient, 185
Why the Interior Is So Hot, 187
Putting It Together—How Hot Is the Interior of Earth?, 188
Where Are You and Where Are You Going?, 188
Active Art, 188
Extension Modules, 188
Confirm Your Knowledge, 189
Confirm Your Understanding, 189
Chapter 9. Making Earth, 190
Why Study the Origin of Earth?, 190
In the Field, 192
9.1. How Did Earth Form?, 192
Finding the Evidence, 192
Extension Module 9.1 A Geologic Tour of the Solar System, 194
Starting with a Cloud of Gas and Dust, 194
Forming the Protosun, 194
Making Planetesimals and Planetary Embryos, 196
Planets and the Sun, 197
Extension Module 9.2 The Origin of the Moon, 197
The Leftovers, 197
Planetary Differentiation, 198
Putting It Together—How Did Earth Form?, 198
9.2. How Did the Core and Mantle Form?, 199
Core Formation from a Magma Ocean, 199
Heat Sources for Magma Ocean and Core Formation, 200
Putting It Together—How Did the Core and Mantle Form?, 201
9.3. How Does the Crust Form?, 201
Oceanic Crust Compared to Continental Crust, 201
The Origin of Oceanic Crust, 201
The Origin of Continental Crust, 201
Putting It Together—How Does the Crust Form?, 202
9.4. How Did the Hydrosphere and Atmosphere Form?, 202
Later Delivery of Water to an Initially Dry Earth, 202
Planetary Embryos Form an Initially Wet Earth, 203
Insights on Water Delivery from Comets and Meteorites, 203
Making the Early Atmosphere, 203
Putting It Together—How Did the Hydrosphere and Atmosphere Form?, 204
9.5. How Do We Know . . . the Hydrosphere Came from the Geosphere?, 205
Define the Problem, 205
State the Hypothesis, 205
Gather the Data, 205
Test the Hypothesis, 205
Insights, 206
Putting It Together—How Do We Know . . . the Hydrosphere Came from the Geosphere?, 206
Where Are You and Where Are You Going?, 206
Extension Modules, 207
Confirm Your Knowledge, 207
Confirm Your Understanding, 207
Chapter 10. Motion Inside Earth, 208
Why Study Earth’s Internal Motion?, 208
In the Lab, 210
10.1. How Does Convection Work?, 210
What Causes Convection Rather Than Conduction?, 211
How Solids Can Convect, 213
Where Can Convection Occur Inside Earth?, 214
Extension Module 10.1 Is Mantle Convection Physically Possible?, 214
Putting It Together—How Does Convection Work?, 214
10.2. What Does Mantle Convection Look Like?, 215
What Heat-Flow Data Show, 215
What Causes the Density Contrasts in the Mantle Required for Convection?, 215
Solid Convection Generates Magma, 215
What Seismic Data Show, 216
What Mantle Convection Should Look Like, 218
Putting It Together—What Does Mantle Convection Look Like?, 219
10.3. How Does Outer-Core Convection Generate the Magnetic Field?, 219
What the Magnetic Field Looks Like, 219
The Magnetic Field Changes with Time, 220
Why Must the Magnetic Field Form in the Core?, 222
How the Magnetic Field Forms, 222
Why Does the Magnetic Field Change?, 223
Putting It Together—How Does Outer-Core Convection Generate the Magnetic Field?, 223
10.4. How Do We Know . . . Earth’s Core Is a Dynamo?, 223
Define the Problem, 223
Build the Simulation, 224
Evaluate the Results, 224
The Unexpected Results, 225
Insights, 225
Putting It Together—How Do We Know . . . Earth’s Core Is a Dynamo?, 225
Where Are You and Where Are You Going?, 226
Active Art, 226
Extension Module, 226
Confirm Your Knowledge, 227
Confirm Your Understanding, 227
Part III. Earth Deformation, 228
Chapter 11. Deformation of Rocks, 228
Why Study Rock Deformation?, 228
In the Field, 230
11.1. What Do Deformed Rocks Look Like?, 232
Describing the Orientation of Rock Layers, 232
Describing Folded Rocks, 232
Describing Broken Rocks, 233
Making a Geologic Map and Cross Section, 235
Putting It Together—What Do Deformed Rocks Look Like?, 237
11.2. How Are Resources Related to Geologic Structures?, 237
Oil and Gas Traps, 237
Metallic Mineral Resources, 239
Putting It Together—How Are Resources Related to Geologic Structures?, 240
11.3. Why Do Rocks Deform?, 240
Rocks Break or Flow When Stress Exceeds Strength, 240
Three Types of Stress and Strain, 240
Faulting, Folding, and Flowing Are Strain, 241
Putting It Together—Why Do Rocks Deform?, 242
11.4. How Do We Know . . . Why Some Rocks Break and Others Flow?, 242
Define the Problem, 242
The Experimental Setup, 242
First Results, 243
Second Results, 244
Insights, 244
Putting It Together—How Do We Know . . . Why Some Rocks Break and Others Flow?, 245
11.5. How Do Geologic Structures Relate to Stress, Strain, and Strength?, 245
Deformation by Tension, 245
Deformation by Compression, 246
Deformation by Shear, 247
How Folds Form Near the Surface, 247
Putting It Together—How Do Geologic Structures Relate to Stress, Strain, and Strength?, 248
11.6. How Do Earthquakes Relate to Rock Deformation?, 248
How Earthquakes Relate to Faults, 248
Fault Movement Without Earthquakes, 249
Elastic Rebound Theory Explains Building Stress Along Faults, 249
Foreshocks, Mainshock, and Aftershocks, 250
Putting It Together—How Do Earthquakes Relate to Rock Deformation?, 251
11.7. How Are Earthquakes Measured?, 251
Measuring Intensity, 251
Measuring Magnitude, 252
Extension Module 11.1 Calculating Magnitude and Energy Released from an Earthquake, 254
Putting It Together—How Are Earthquakes Measured?, 255
11.8. Why Are Earthquakes Destructive?, 255
Ground Shaking, 255
Tsunami, 258
Risk Assessment Tools, 258
Earthquake Prediction, 259
Putting It Together—Why Are Earthquakes Destructive?, 259
Extension Module 11.2 Mitigating and Forecasting Earthquake Hazards, 259
Where Are You and Where Are You Going?, 260
Active Art, 260
Extension Modules, 260
Confirm Your Knowledge, 261
Confirm Your Understanding, 261
Chapter 12. Global Tectonics: Plates and Plumes, 262
Why Study Tectonic Plates and Their Motions?, 262
In the Lab, 264
12.1. How Does Continental Drift Relate to Plate Tectonics?, 266
Putting It Together—How Does Continental Drift Relate to Plate Tectonics?, 266
12.2. What Is the Evidence That Plates Are Rigid?, 266
What Surface Deformation Reveals, 266
What the Locations of Volcanoes Reveal, 269
What the Distribution of Mountain Belts Suggests, 269
Putting It Together—What Is the Evidence That Plates Are Rigid?, 270
12.3. What Is the Evidence That Plates Move Apart at Divergent Boundaries?, 271
What Do Divergent Plate Boundaries Look Like?, 271
What Oceanic-Crust Composition Reveals, 271
The Significance of Mid-Ocean Earthquakes and Faults, 271
What the Age and Magnetism of Oceanic Crust Reveal, 271
What Heat-Flow Data Show, 274
What Seismic Tomography Reveals, 274
The Significance of Continental Rift Valleys, 275
Putting It Together—What Is the Evidence That Plates Move Apart at Divergent Plate Boundaries?, 277
12.4. What Is the Evidence That Subduction Occurs at Convergent Plate Boundaries?, 277
What Does a Convergent Boundary Look Like?, 277
What Happens at Convergent Boundaries?, 278
What Earthquakes Reveal, 278
What Seismic Tomography Data Reveal, 278
What Heat-Flow Data Reveal, 279
Why Does Subduction Occur?, 280
The Types of Convergent Plate Boundaries, 281
Putting It Together—What Is the Evidence That Subduction Occurs at Convergent Plate Boundaries?, 282
12.5. What Is the Evidence That Plates Slide Past One Another at Transform Plate Boundaries?, 282
What a Transform Boundary Looks Like, 282
What Fault Displacements Show, 282
What Earthquakes on Oceanic Transforms Show, 282
Putting It Together—What Is the Evidence That Plates Slide Past One Another at Transform Plate Boundaries?, 284
12.6. What Does the Mantle-Plume Hypothesis Explain that Plate Tectonics Cannot Explain?, 284
The Problem of Hot Spots, 284
The Mantle-Plume Hypothesis, 284
Testing the Plume Hypothesis, 287
Putting It Together—What Does the Mantle-Plume Hypothesis Explain that Plate Tectonics Cannot Explain?, 288
12.7. How Do We Know . . . That Plates Move in Real Time?, 288
Understand the Problem, 288
Visualize Relative and Absolute Motion, 288
Extension Module 12.1 Describing Plate Motion on the Surface of a Sphere, 288
Test the Predictions, 288
Evaluate the Results, 290
Insights, 290
Putting It Together—How Do We Know . . . That Plates Move in Real Time?, 292
12.8. What Causes Plate Motion and Plumes?, 292
Downwelling at Convergent Boundaries, 292
Upwelling at Plumes, Superplumes, and Divergent Boundaries, 293
Putting It Together—What Forces Cause Plate Motion and Plumes?, 293
12.9. What Are the Consequences of Plate Motion over Geologic Time?, 293
Reconstructing Past Plate Motions, 293
Extension Module 12.2 Using Paleomagnetism to Reconstruct Past Continental Positions, 293
Paleozoic Plate Tectonics, 293
Mesozoic Plate Tectonics, 295
Cenozoic Plate Tectonics, 295
Putting It Together—What Are the Consequences of Plate Motion over Geologic Time?, 295
Where Are You and Where Are You Going?, 296
Active Art, 296
Extension Modules, 296
Confirm Your Knowledge, 297
Confirm Your Understanding, 297
Chapter 13. Tectonics and Surface Relief, 298
Why Study Surface Relief?, 298
In the Field, 300
13.1. Why Are Continents High and Oceans Low?, 300
Elevation Relates to Crust Type, 300
Isostasy Determines Elevation, 301
Demonstrating Isostasy in a Tub of Water, 302
How Isostasy Explains Elevations of Continents and Oceans, 304
Putting It Together—Why Are Continents High and Oceans Low?, 305
13.2. How Do We Know . . . That Mountains Have Roots?, 305
Define the Problem, 305
Examine Two Historical Hypotheses, 305
Evaluate the Hypotheses, 305
Insights, 307
Putting It Together—How Do We Know . . . That Mountains Have Roots?, 307
13.3. How Does Isostasy Relate to Active Geologic Processes?, 307
The Effects of Tectonic Shortening and Stretching, 307
The Effects of Erosion and Deposition, 307
What Elevation Changes Related to Ice-Age Glaciers Reveal About Isostasy, 309
Isostatic Adjustment Causes Earthquakes, 311
Putting It Together—How Does Isostasy Relate to Active Geologic Processes?, 311
13.4. Why Does Sea Level Change?, 311
Changing the Volume of Water in the Container, 312
Changing the Size of the Container, 312
How Isostasy Explains Water Depth in Oceans, 313
Sea Level Changes when Average Lithosphere Age Changes, 313
Putting It Together—Why Does Sea Level Change?, 313
13.5. How and Where Do Mountains Form?, 313
Mountain Belts Near Continental Margins, 314
Mountain Belts Where Continents Collide, 315
The Role of the Mantle in Surface Topography, 316
How Fast Do Mountains Rise?, 316
Extension Module 13.1 Measuring Uplift Rates, 317
Putting It Together—How and Where Do Mountains Form?, 317
13.6. How Does Mountain Building Relate to Continent Growth?, 317
Assembly at Subduction Zones, 317
Making the Ancient Continental Centers, 319
Putting It Together—How Does Mountain Building Relate to the Growth of Continents?, 321
Where Are You and Where Are You Going?, 322
Active Art, 322
Extension Module, 322
Confirm Your Knowledge, 322
Confirm Your Understanding, 323
Part IV. Surface and Near Surface Processes, 324
Chapter 14. Soil Formation and Landscape Stability, 324
Why Study Soils?, 324
In the Field, 326
14.1. What Is Soil?, 326
A Geologic Definition of Soil, 326
Soil Forms from Parent Material, 328
Putting It Together—What Is Soil?, 328
14.2. What Distinguishes Soil Horizons?, 328
Horizons Close to the Surface: A, O, and E, 328
The Middle Horizon of Mineral Accumulation: B, 329
The Bottom Horizon of the Soil: C, 330
Soil Horizons Result from Mineral Additions, Subtractions, and Transformations, 330
Putting It Together—What Distinguishes Soil Horizons?, 330
14.3. How Do Soils Form?, 330
Explaining Mineral Subtractions from A and E Horizons, 330
Explaining Soil Fertility and Infertility, 331
Explaining Mineral Additions and Transformations in the B Horizon, 331
Explaining Calcite in Desert Soil, 332
Putting It Together—How Do Soils Form?, 333
14.4. What Factors Determine Soil Characteristics?, 333
The Role of Parent Material, 333
The Role of Climate, 333
The Role of Vegetation, 334
The Role of Time, 334
The Role of Landscape Relief, 335
Putting It Together—What Factors Determine Soil Characteristics?, 335
14.5. What Are the Types of Soils?, 336
Forest Soils, 336
Rainforest Soils, 336
Grassland Soils, 337
Desert Soils, 339
Wetland Soils, 339
Soils with Weakly Developed Horizons, 340
Putting It Together—What Are the Types of Soils?, 340
14.6. How Do We Know . . . That Soils Include Atmospheric Additions?, 341
Picture the Problem, 341
State the Hypothesis, 341
Collect the Data, 342
Use the Data, 342
Insights, 343
Putting It Together—How Do We Know . . . That Soils Include Atmospheric Additions?, 343
14.7. How Do Human Activities Affect Soils?, 343
Soil Erosion by Flowing Water, 344
Soil Erosion by Blowing Wind, 344
Preventing Soil Erosion, 345
Putting It Together—How Do Human Activities Affect Soils?, 346
Where Are You and Where Are You Going?, 346
Confirm Your Knowledge, 347
Confirm Your Understanding, 347
Chapter 15. Mass Movements: Landscapes in Motion, 348
Why Study Landslides?, 348
In the Field, 350
15.1. What Are the Characteristics of Mass Movements?, 353
Criteria for a Meaningful Classification, 353
Distinguishing the Materials in Motion, 353
Mass Movement by Free Fall, 353
Mass Movement by Sliding Along a Surface, 354
Mass Movement by Flow Resembling a Liquid, 355
Single Events—Multiple Processes, 356
Putting It Together—What Are the Characteristics of Mass Movements?, 357
15.2. What Causes Mass Movements?, 357
Using an Analogy of Mass Movement, 357
Gravity Is the Driving Force, 357
Friction and Cohesion Are the Resisting Forces, 357
Driving Force Greater than Resisting Force Equals Movement, 358
Putting It Together—What Causes Mass Movements?, 360
15.3. What Factors Determine Slope Stability?, 360
The Role of Water, 360
The Role of Geologic Materials, 360
The Role of Slope, 361
The Role of Geologic Structures, 361
The Role of Weathering, 361
The Role of Vegetation, 361
Putting It Together—What Factors Determine Slope Stability?, 362
15.4. When Do Mass Movements Occur?, 363
Rainfall and Snowmelt Triggers, 363
Earthquake Triggers, 363
Volcanic Eruption Triggers, 363
Putting It Together—When Do Mass Movements Occur?, 366
15.5. How Do We Know . . . How to Map Mass-Movement Hazards?, 366
Picture the Goal, 366
Assembling the Data, 367
Applying the Tool, 368
Picture the Results, 368
Insights, 369
Putting It Together—How Do We Know . . . How to Map Mass-Movement Hazards?, 369
15.6. How Do Mass Movements Sculpt the Landscape?, 369
Mass Movements and Mountain Building Go Together, 369
Mass Movements Move Mountains, 369
Putting It Together—How Do Mass Movements Sculpt the Landscape?, 370
Where Are You and Where Are You Going?, 371
Active Art, 371
Confirm Your Knowledge, 371
Confirm Your Understanding, 371
Chapter 16. Streams: Flowing Water Shapes the Landscape, 372
Why Study Streams?, 372
In the Field, 374
16.1. Where Does the Water Come From?, 376
The Hydrologic Cycle, 376
The Drainage Basin: The Area Where the Water Comes From, 376
Discharge: The Amount of Water Flowing in a Stream, 377
Extension Module 16.1 How a Stream Gage Works, 377
Putting It Together—Where Does the Water Come From?, 378
16.2. Where Does Sediment Come From?, 378
The Sources of Sediment in Streams, 378
How Much Sediment Do Streams Carry?, 378
Putting It Together—Where Does Sediment Come From?, 380
16.3. How Do Streams Pick Up Sediment?, 380
How Alluvial Streams Pick Up Loose Sediment, 380
How Bedrock Streams Break Off Pieces of Rock, 381
Putting It Together—How Do Streams Pick Up Sediment?, 382
16.4. How Do Streams Transport Sediment?, 383
Sediment Moves as Bedload and Suspended Load, 383
Stream Power Limits Sediment Transport, 383
Putting It Together—How Do Streams Transport Sediment?, 384
16.5. Why Do Streams Deposit Sediment?, 384
Deposition Happens When Discharge Decreases, 384
Deposition Happens Where Water Depth Decreases, 384
Deposition Happens Where Slope Decreases, 385
Deposition Happens Where Velocity Decreases, 385
Putting It Together—Why Do Streams Deposit Sediment?, 386
16.6. Why Does a Stream Change Along Its Course?, 386
Streams Adjust to Carry Available Water and Sediment, 386
Streams Become Wider, Deeper, and Faster Downstream, 387
Slope Decreases Along the Base Level of Erosion, 387
Sediment Size Decreases Downstream, 388
Putting It Together—Why Does a Stream Change Along Its Course?, 388
16.7. What Factors Determine Channel Pattern?, 388
Meandering and Braided Channels, 388
The Roles of Bedload and Discharge in Determining Channel Pattern, 388
The Roles of Suspended Load and Slope in Determining Channel Pattern, 388
The Role of Banks in Determining Channel Pattern, 388
Putting It Together—What Factors Determine Channel Pattern?, 390
16.8. How Does a Floodplain Form?, 390
Shifting Channels Make Floodplains, 390
Overbank Flooding Builds Up Floodplains, 391
Putting It Together—How Does a Floodplain Form?, 392
16.9. Why Do Streams Flood?, 392
Flash Floods, 392
Prolonged Floods, 393
Putting It Together—Why Do Streams Flood?, 394
16.10. How Do We Know . . . the Extent of the “100-Year Flood”?, 394
Picture the Problem, 394
Design the Analysis, 394
Analyze the Discharge Data, 394
Analyze the Water Depth, 396
Insights, 396
Putting It Together—How Do We Know . . . the Extent of the “100-Year Flood”?, 396
Extension Module 16.2 How to Determine Recurrence Intervals of Floods, 397
Extension Module 16.3 How to Reduce Flood Hazards, 397
16.11. How Do Human Activities Affect Streams?, 397
How Dams Affect Rivers, 397
How Changing Land Use Affects Rivers, 397
Putting It Together—How Do Human Activities Affect Streams?, 398
16.12. How Do Stream-Formed Landscapes Change Through Geologic Time?, 398
Terraces—Evidence of Downcutting and Filling of Valleys, 398
How Climate Changes River Characteristics, 399
How Tectonics Changes River Characteristics, 400
Incised Rivers—Tectonics or Climate?, 401
How Sea-Level Variation Changes River Characteristics, 401
How Bedrock Geology Affects Landscape Development, 402
Putting It Together—How Do Stream-Formed Landscapes Change through Geologic Time?, 402
16.13. How Do Lakes Form?, 403
How to Naturally Dam a River, 403
How Tectonic Activity Forms Lakes, 403
Putting It Together—How Do Lakes Form?, 405
Where Are You and Where Are You Going?, 405
Active Art, 406
Extension Modules, 406
Confirm Your Knowledge, 406
Confirm Your Understanding, 406
Chapter 17. Water Flowing Underground, 408
Why Study Ground Water?, 408
In the Field, 410
17.1. What Is Ground Water and Where Is It Found?, 412
How Ground Water Is Stored in Rock and Regolith, 412
Locating Ground Water, 412
Extension Module 17.1 Anatomy of a Water Well, 413
Ground Water Flows, 414
The Water Table Separates Saturated and Unsaturated Zones, 415
Why Water Sometimes Is Found at Surprisingly Shallow Depths, 416
Characteristics of Aquifers, 416
The Water-Table Level Changes Through Time, 417
Putting It Together—What Is Ground Water and Where Is It Found?, 420
17.2. Why and How Does Ground Water Flow?, 420
Ground Water Flows from Areas of High Energy to Areas of Low Energy, 420
Extension Module 17.2 Darcy’s Law, 421
Where Ground Water Flows, 421
Deeply Flowing Ground Water Forms Hot Springs, 421
Why the Water Table Is Lower Near a Pumping Well, 423
Why Ground Water Sometimes Flows Higher than the Ground Surface, 423
Pollution Also Moves in Ground Water, 424
Putting It Together—Why and How Does Ground Water Flow?, 425
17.3. How Do We Know . . . How Fast Ground Water Moves?, 426
Picture the Problem, 426
Design the Experiment, 426
Analyze the Data, 427
Insights, 428
Putting It Together—How Do We Know . . . How Fast Ground Water Moves?, 428
17.4. What Is the Composition of Ground Water?, 429
Water-Mineral Reactions in Aquifers, 429
Hard and Soft Water, 430
Ground Water Forms Economic Mineral Deposits, 430
Ground-Water Chemistry Near Coastlines, 430
Unnatural Additions: Ground-Water Pollution, 431
Putting It Together—What Is the Composition of Ground Water?, 432
17.5. How Does Ground Water Shape the Landscape?, 432
Landscapes Molded by Ground-Water Dissolution of Rock, 432
Extension Module 17.3 The Geology of Caves, 434
Landscapes Molded by Seeping Ground Water, 435
Putting It Together—How Does Ground Water Shape the Landscape?, 436
Where Are You and Where Are You Going?, 436
Active Art, 436
Extension Modules, 436
Confirm Your Knowledge, 437
Confirm Your Understanding, 437
Chapter 18. Glaciers: Cold-Climate Sculptors of Continents, 438
Why Study Glaciers?, 438
In the Field, 440
18.1. What Is a Glacier?, 443
Types of Glaciers, 443
Where Glaciers Form, 443
Sizes of Glaciers, 443
Putting It Together—What Is a Glacier?, 444
18.2. How Does Glacial Ice Form?, 444
Snow Metamorphism, 444
How Much Time and Pressure Are Necessary to Make Glacial Ice?, 444
Putting It Together—How Does Glacial Ice Form?, 445
18.3. How Does Ice Flow?, 445
How Fast Do Glaciers Move?, 445
Glacial Ice Is Weak Rock, 445
Flow from Where Ice Builds Up to Where It Melts, 446
Why It Is Important to Know the Bottom Temperature of a Glacier, 448
Putting It Together—How Does Ice Flow?, 448
18.4. How Do Glaciers Erode and Transport Sediment?, 448
Comparing Glaciers and Rivers, 448
Glaciers Exert Shear Stress, 448
The Role of Meltwater, 448
Erosion by Abrasion, 449
Erosion by Plucking, 449
Contributions from the Freeze-Thaw Process and Mass Movement, 450
Where Erosion Occurs, 450
The Transport of Sediment on Top of, Within, and Below Glaciers, 450
The Rates of Glacial Erosion, 450
Putting It Together—How Do Glaciers Erode and Transport Sediment?, 451
18.5. How Do Glaciers Deposit Sediment?, 451
The Sediment Left Behind, 452
Sediment Deposited at the Glacier Margin, 452
Sediment Deposited by Meltwater Streams, 452
Putting It Together—How Do Glaciers Deposit Sediment?, 453
18.6. What Happens When Glaciers Reach the Ocean?, 454
The Formation of Tidewater Glaciers and Ice Shelves, 454
Making Icebergs, 454
Putting It Together—What Happens when Glaciers Reach the Ocean?, 456
18.7. How Do Valley Glaciers Modify the Landscape?, 456
U-Shaped Valleys, 456
Overdeepened Valleys, 456
Hanging Valleys, 459
Knife-Edged Ridges and Pointed Peaks, 459
Lateral and End Moraines, 459
Putting It Together—How Do Valley Glaciers Modify the Landscape?, 459
18.8. How Do Ice Sheets Modify the Landscape?, 460
Widespread Scour of Bedrock, 460
Thick Till and Long Moraines, 461
Streamlined Features in Rock and Till, 462
Glacially Formed Lakes, 462
Putting It Together—How Do Ice Sheets Modify the Landscape?, 463
18.9. What Did North America Look Like During the Last Ice Age?, 463
The Extent of Glaciers, 463
Where the Ice Sheets Came From, 463
Lower Sea Levels and the Bering Land Connection, 464
Landscapes Beyond the Glaciers, 464
Extension Module 18.1 Ice Age Lakes in the Great Basin, 465
Landscape Changes During Glacial Retreat, 465
Extension Module 18.2 Humongous Ice-Age Floods in the Pacific Northwest, 466
Implications for Soil Formation and Fertility, 466
Putting It Together—What Did North America Look Like During the Last Ice Age?, 468
18.10. How Do We Know . . . How to Determine When Ice Ages Happened?, 468
Picture the Problem, 468
The Background of the Method, 468
Collect the Data, 469
Insights, 469
Extension Module 18.3 Ice Ages Through Earth’s History, 470
Putting It Together—How Do We Know . . . How to Determine When Ice Ages Happened?, 470
18.11. What Causes Ice Ages?, 470
Variations in Earth’s Rotation and Orbit, 470
Variations in Solar Heating of Earth’s Surface, 472
Putting It Together—What Causes Ice Ages?, 472
Where Are You and Where Are You Going?, 472
Active Art, 473
Extension Modules, 473
Confirm Your Knowledge, 473
Confirm Your Understanding, 473
Chapter 19. Shorelines: Changing Landscapes Where Land Meets Sea, 474
Why Study Shorelines?, 474
In the Field, 476
19.1. What Factors Determine the Shape of a Shoreline?, 478
Putting It Together—What Factors Determine the Shape of a Shoreline?, 478
19.2. How Do Waves Form and Move in Water?, 478
What Are Waves?, 478
How Water Waves Form, 479
How Waves Move Water, 480
What Happens When Waves Approach the Shoreline?, 481
How Waves Generate Currents, 482
How Tsunami Waves Are Different from Other Waves, 483
Putting It Together—How Do Waves Form and Move in Water?, 485
19.3. How Do Waves Form Shoreline Landscapes?, 485
How Waves Erode, Transport, and Deposit Sediment, 485
How Waves Shape Rocky Shorelines, 487
How Waves Make Beaches, 487
How Longshore Currents Shape Shorelines, 490
Sediment Sources for Beaches, 491
The Sediment Budget Determines Beach Growth or Loss, 491
How Barrier Islands and Tidal Inlets Form, 493
Putting It Together—How Do Waves Form Shoreline Landscapes?, 495
19.4. What Is the Role of Tides in Forming Coastal Landscapes?, 495
Why Tides Exist, 495
Where Tides Affect the Shoreline, 495
How Tidal Flats Form, 496
Tidal Processes at Inlets, 498
Tides as an Energy Source, 498
Putting It Together—What Is the Role of Tides in Forming Coastal Landscapes?, 498
19.5. Why Does Shoreline Location Change Through Time?, 499
Processes That Change Shoreline Location, 499
Submergent and Emergent Shorelines, 499
Evidence That Uplift and Subsidence Change Shorelines, 501
Evidence That Sediment Deposition and Erosion Change Shorelines, 501
Putting It Together—Why Does Shoreline Location Change Through Time?, 503
19.6. How Do We Know . . . That Global Sea Level Is Rising?, 503
Picture the Problem, 503
Examine the Evidence for Historic Sea-Level Change, 503
Examine the Evidence for Prehistoric Sea-Level Change, 504
Integrate the Data Sets, 505
Insights, 505
Putting It Together—How Do We Know . . . That Global Sea Level Is Rising?, 505
19.7. What Are the Consequences of Rising Sea Level?, 505
The Effects of Rising Sea Level on Beaches and Barrier Islands, 507
The Effects of Rising Sea Level on Estuaries, 507
The Effects of Rising Sea Level on Deltas, 508
The Effects of Rising Sea Level on Sea Cliffs, 508
Human Responses to Shoreline Erosion, 508
Putting It Together—What Are the Consequences of Rising Sea Level?, 510
Extension Module 19.1 Changing Shorelines in the Great Lakes, 510
Where Are You and Where Are You Going?, 510
Active Art, 511
Extension Module, 511
Confirm Your Knowledge, 511
Confirm Your Understanding, 511
Chapter 20. Wind: A Global Geologic Process, 512
Why Study Wind?, 512
In the Field, 514
20.1. Why Does Wind Blow?, 516
What Is Wind?, 516
Constructing Global Wind Patterns, 516
Extension Module 20.1 How the Coriolis Effect Works, 518
Local Wind Patterns, 518
Putting It Together—Why Does Wind Blow?, 518
20.2. Where Is Wind an Influential Process in the Landscape?, 519
Wind Is Effective Where Vegetation Is Sparse or Absent, 519
Wind Is Effective Where Surface Particles Are Small, 520
Putting It Together—Where Is Wind an Influential Process in the Landscape?, 520
20.3. What Determines the Locations of Deserts?, 520
Subtropical Deserts, 520
Rain-Shadow Deserts, 520
Coastal Deserts, 522
Polar Deserts, 522
Putting It Together—What Determines the Locations of Deserts?, 522
20.4. How Does Wind Pick Up and Transport Sediment?, 523
Getting Particles in Motion, 523
Transporting Particles, 523
Putting It Together—How Does Wind Pick Up and Transport Sediment?, 525
20.5. How Does Wind Shape the Landscape?, 525
Landscapes Eroded by Wind, 525
The Variety of Sand Dunes, 527
Blankets of Loess, 527
Desert Pavements: Formed by Sediment Deflation or Accumulation?, 528
Wind-Formed Landscapes of the Recent Past, 531
Putting It Together—How Does Wind Shape the Landscape?, 532
20.6. How Do We Know . . . That Wind Blows Dust Across Oceans?, 532
Picture the Problem, 532
Develop a Hypothesis, 533
Test the Hypothesis, 533
Insights, 535
Putting It Together—How Do We Know . . . That Wind Blows Dust Across Oceans?, 535
Where Are You and Where Are You Going?, 535
Active Art, 536
Extension Module, 536
Confirm Your Knowledge, 536
Confirm Your Understanding, 537
Chapter 21. Global Warming: Real-Time Change in the Earth System, 538
Why Study Climate Change?, 538
In the Lab, 540
21.1. What Is the Evidence for Global Warming?, 540
The Evidence from Local Temperature Records, 541
The Evidence from Global Temperature Records, 542
The Supporting Evidence from Glacier Observations, 543
The Supporting Evidence from Sea-Level Measurements, 544
Putting It Together—What Is the Evidence for Global Warming?, 545
21.2. What Is the Geologic Record of Climate Change?, 545
How Paleoclimate Is Reconstructed, 545
Climate Change Before the Quaternary Period, 547
Fluctuating Quaternary Climate, 548
The Climate of the Last 1000 Years, 549
Putting It Together—What Is the Geologic Record of Climate Change?, 550
21.3. Why Does Climate Change?, 550
The Energy Budget, 550
Identifying Factors That Change in the Energy Budget, 551
Ocean Circulation and Climate, 553
Putting It Together—Why Does Climate Change?, 553
21.4. What Natural Processes and Human Activities Affect Global Temperature?, 554
Changes in Solar Energy, 554
Changes in Albedo, 554
Changes in Atmosphere Composition by Human Activities, 555
How Greenhouse-Gas Concentrations Relate to the Carbon Cycle, 556
The Effects of Volcanic Eruptions on Atmosphere Composition, 558
Balancing the Energy Budget, 558
Changes in Ocean Circulation, 559
Putting It Together—What Natural Processes and Human Activities Affect Global Temperature?, 561
21.5. How Do We Know . . . That Humans Cause Global Warming?, 562
Define the Problem, 562
Build a Computer Model, 562
Evaluate the Results, 563
Insights, 564
Putting It Together—How Do We Know . . . That Humans Cause Global Warming?, 564
21.6. How Will Climate Change in the Future?, 564
Computer Models of Future Climate, 564
Uncertainty and Skepticism, 566
Putting It Together—How Will Climate Change in the Future?, 567
Where Are You and Where Are You Going?, 567
Active Art, 568
Confirm Your Knowledge, 568
Confirm Your Understanding, 569
Appendix A. Periodic Table of the Elements, A-1
Appendix B. Ions and Natural Isotopes that Are Significant to Geologic Studies, A-2
Appendix C. Common Conversions, A-3
Glossary, G-1
Credits, C-1
Index, I1

Search Results

« Back to eTextbook


PAGE	Description

iv	...

Tabs for Contents, notes, highlights

Table of Contents

Search Results