Understanding Earth » (6th Edition)

More than any other introductory physical geology textbook, Understanding Earth is designed to bring the worldview of the working geologist to an audience not only new to this specific field, but in many cases to science in general. Students aren't merely presented with concepts and processes--they come to learn how we know what we know, and how that knowledge impacts their lives as citizens and consumers.

Meet the Authors     vi
Preface     xiii
The Modern Theory and Practice of Geology
The Earth System     1
The Scientific Method     2
Earth's Shape and Surface     3
The Geologic Record     4
Peeling the Onion: Discovery of a Layered Earth     6
Earth as a System of Interacting Components     10
An Overview of Geologic Time     14
Plate Tectonics: The Unifying Theory     18
The Discovery of Plate Tectonics     19
The Mosaic of Plates     22
Rates and History of Plate Motions     30
The Grand Reconstruction     35
Mantle Convection: The Engine of Plate Tectonics     37
The Theory of Plate Tectonics and the Scientific Method     42
Basic Geologic Processes
Earth Materials: Minerals and Rocks     44
What Are Minerals?     45
The Atomic Structure of Matter     46
Chemical Reactions     47
Chemical Bonds     49
The Atomic Structure of Minerals     49
Rock-Forming Minerals     52
Physical Properties of Minerals     56
What Are Rocks?     62
Igneous Rocks     63
SedimentaryRocks     64
Metamorphic Rocks     66
The Rock Cycle: Interactions Between the Plate Tectonic and Climate Systems     66
Minerals Occur in Rocks as Valuable Resources     68
Earth Issues: Sulfide Minerals React to Form Acid Waters on Earth and Mars     57
Igneous Rocks: Solids from Melts     76
How Do Igneous Rocks Differ from One Another?     78
How Do Magmas Form?     83
Where Do Magmas Form?     85
Magmatic Differentiation     85
Forms of Magmatic Intrusions     88
Igneous Activity and Plate Tectonics     91
Sedimentation: Rocks Formed by Surface Processes     100
Sedimentary Rocks Are Produced by Surface Processes in the Rock Cycle     102
Sedimentary Basins: The Sinks for Sediments     106
Sedimentary Environments     108
Sedimentary Structures     111
Burial and Diagenesis: From Sediment to Rock     114
Classification of Siliciclastic Sediments and Sedimentary Rocks     116
Classification of Chemical and Biological Sediments and Sedimentary Rocks     119
Earth Policy: Darwin's Coral Reefs and Atolls     124
Metamorphism: Modification of Rocks by Temperature and Pressure      130
Metamorphism and the Earth System     132
Causes of Metamorphism     133
Types of Metamorphism     134
Metamorphic Textures     136
Regional Metamorphism and Metamorphic Grade     141
Plate Tectonics and Metamorphism     144
Deformation: Modification of Rocks by Folding and Fracturing     150
Mapping Geologic Structure     152
How Rocks Deform     154
Basic Deformation Structures     156
Styles of Continental Deformation     163
Unraveling Geologic History     165
Earth and Planets Through Geologic Time
Clocks in Rocks: Timing the Geologic Record     168
Reconstructing Geologic History from the Stratigraphic Record     170
Geologic Time Scale: Relative Ages     178
Measuring Absolute Time with Radioactive Clocks     180
Geologic Time Scale: Absolute Ages     183
Timing the Earth System     184
Earth Issues: The Grand Canyon Sequence and Regional Correlation of Strata     176
Early History of the Terrestrial Planets     188
Origin of the Solar System     190
Early Earth: Formation of a Layered Planet     192
Diversity of the Planets     195
What's in a Face? The Age and Complexion of Planetary Surfaces     197
Mars Rocks!     204
Exploring the Solar System and Beyond     210
Evolution of the Continents     214
The Tectonics of North America     216
Tectonic Provinces Around the World     221
How Continents Grow     224
How Continents Are Modified     226
The Formation of Cratons     235
The Deep Structure of Continents     236
Geobiology: Life Interacts with the Earth     240
The Biosphere as a System     242
Microbes: Nature's Tiny Chemists     246
Geobiological Events in Earth's History     254
Astrobiology: The Search for Extraterrestrial Life     265
Earth Issues: The Mother of all Mass Extinctions: Whodunit?     264
Internal Geosystems
Volcanoes     270
Volcanoes as Geosystems     272
Lavas and Other Volcanic Deposits     273
Eruptive Styles and Landforms     277
Geosystem Interactions     282
The Global Pattern of Volcanism     284
Volcanism and Human Affairs     288
Earth Policy: Mount St. Helens: Dangerous but Predictable     292
Earthquakes     296
What Is an Earthquake?     298
Studying Earthquakes     301
Earthquakes and Patterns of Faulting     309
Earthquake Destructiveness     313
Can Earthquakes Be Predicted?     320
Earth Issues: The Great Indian Ocean Tsunami of 2004     312
Earth Issues: Seven Steps to Earthquake Safety     319
Exploring: Earth's Interior     324
Exploring the Interior with Seismic Waves     325
Layering and Composition of the Interior     328
Earth's Internal Heat and Temperature     332
The Three-Dimensional Structure of the Mantle     338
Earth's Magnetic Field and the Geodynamo     337
Earth Issues: The Uplift of Scandinavia: Nature's Experiment with Isostasy     331
Earth Issues: The Geoid: Shape of Planet Earth     338
Surficial Geosystems
The Climate System     346
Components of the Climate System     348
The Greenhouse Effect     352
Climate Variability     355
The Carbon Cycle     362
Twentieth-Century Warming: Human Fingerprints of Global Change     366
Earth Issues: Vostok and GRIP: Ice-Core Drilling in Antarctica and Greenland     358
Earth Issues: El Nino: The Wayward Child      360
Weathering, Erosion, and Mass Wasting: Interface Between Climate and Tectonics     370
Weathering, Erosion, Mass Wasting, and the Rock Cycle     372
Controls on Weathering     372
Chemical Weathering     373
Physical Weathering     378
Soil: The Residue of Weathering     381
Mass Wasting     384
Classification of Mass Movements     388
Understanding the Origins of Mass Movements     395
The Hydrologic Cycle and Groundwater     400
Flows and Reservoirs     402
Hydrology and Climate     404
The Hydrology of Runoff     406
Groundwater     408
Water Resources from Major Aquifers     415
Erosion by Groundwater     417
Water Quality     418
Water Deep in the Crust     421
Earth Issues: Water Is a Precious Resource: Who Should Get It?     404
Earth Issues: When Do Groundwaters Become Nonrenewable Resources?     416
Stream Transport: From Mountains to Oceans     426
Stream Valleys, Channels, and Floodplains     428
Drainage Networks     432
Where Do Channels Begin? How Running Water Erodes Solid Rock     435
How Stream Waters Flow and Transport Sediment     437
Deltas: The Mouths of Rivers     440
Streams as Geosystems     443
Earth Issues: The Development of Cities on Floodplains     432
Winds and Deserts     452
Wind as a Flow of Air     454
Wind as a Transport Agent     455
Wind as an Agent of Erosion     458
Wind as a Depositional Agent     460
The Desert Environment     464
Earth Issues: Martian Dust Storms and Dust Devils     457
Coastlines and Ocean Basins     472
Basic Differences Between Ocean Basins and Continents     474
Coastal Processes     474
Shorelines     485
Sea Level Change as a Measure of Global Warming     488
Continental Margins     491
The Deep Oceans     494
Ocean Sedimentation     500
Earth Policy: The Great New Orleans Flood     480
Earth Issues: Preserving Our Beaches     490
Glaciers: The Work of Ice     504
Ice as a Rock     506
How Glaciers Form     508
How Glaciers Move     511
Glacial Landscapes     515
Glaciations and the Climate System     522
Earth Issues: Isostasy and Sea-Level Change     524
Landscapes: Tectonic and Climate Interaction     530
Topography, Elevation, and Relief     532
Landforms: Features Sculpted by Erosion and Sedimentation     535
Interacting Geosystems Control Landscape     541
Models of Landscape Evolution     545
Earth Issues: Uplift and Climate Change: A Chicken-and-Egg Dilemma     544
Earth Science and Society
The Human Impact on Earth's Environment     550
Civilization as a Global Geosystem     552
Fossil-Fuel Resources     556
Alternative Energy Resources     564
Global Change     569
Welcome to the Anthropocene: A New Geologic Epoch     574
Earth System Engineering and Management     575
Earth Policy: Subsurface Toxic and Nuclear Waste Contamination     566
Earth Policy: The Kyoto Accords and the Politics of Climate Change     577
Conversion Factors     AP-1
Numerical Data Pertaining to Earth     AP-2
Chemical Reactions     AP-3
Properties of the Most Common Minerals of Earth's Crust     AP-4
Glossary     GL-1
Suggested Readings     SR-1
Index     I-1