Exploring Earth : An Introduction to Physical Geology

by Davidson, Jon P.; Reed, Walter E.; Davis, Paul M.

• ISBN13: 9780130183729
• ISBN10: 0130183725
• Edition: 2nd
• Format: Paperback
• Copyright: 2002-01-01
• Publisher: Benjamin Cummings

Summary

For an introductory physical geology course taught at both two- and four-year schools. Exploring Earth takes an integrative, process approach to teaching physical geology by presenting the traditional breadth of topics using plate tectonics as a unifying theme. These highly respected researchers and teachers explore the science of geology with the reader via clear, comprehensible prose and an exceptional art program.

Table of Contents

(NOTE: Each chapter begins with Overview and Introduction and concludes with Summary, Key Terms, and Questions for Review and Further Thought.)

I: PLANET EARTH: ACTING AND INTERACTING.

1. The Changing Planet: Earth as a System.

Understanding Earth: The Question of Scale. Geologic Time: An Important Perspective. A Process Approach to Physical Geology. Focus 1.1: Earth Systems and Connections: Can Plate Tectonics Cause Ice Ages? Focus 1.2: A Matter of Perspective: Big and Small Numbers. Focus 1.3: The Philosophy of Science.

2. Earth: Origin and Composition.

The Composition of the Universe. The Building Blocks of the Universe. Our Solar System. The Planet Earth. The Future of Earth and Our Solar System. Focus 2.1: A Chemistry Refresher: Atoms and Molecules. Focus 2.2: The Doppler Shift: Evidence for the Expanding Universe and Other Solar Systems. Focus 2.3: Impacts and Their Effects on Earth. Focus 2.4: Planetary Density. Focus 2.5: The Moon.

II: COMPOSITION AND TIME.

3. Minerals: The Building Blocks of Rocks.

What Is a Mineral? Crystals. Mineral Properties. Mineral Groups. Distribution of Elements and Minerals in Earth. Focus 3.1: A Chemistry Refresher: Atoms and the Periodic Table. Focus 3.2: Determining Crystal Structures and Compositions. Focus 3.3: Mineral Stability and Phase Diagrams. Focus 3.4: Thin Sections.

4. The Cornerstones of Geology: Rocks!

Igneous Rocks. Sedimentary Rocks. Metamorphic Rocks. The Rock Cycle. Focus 4.1: Simulating Earths' Interior. Focus 4.2: Crystallization of Lava: The Hawaiian Lava Lake. Focus 4.3: Determining Metamorphic Pressures and Temperatures. Focus 4.4: Getting Information from Rocks: Observation and Interpretation.

5. Earth Processes: Physical Principles.

Seismic Waves. Velocity Variations within Earth. Gravity and Isostasy. Geomagnetism. Focus 5.1: The Velocities of Seismic Waves. Focus 5.2: Isostasy: Controls on Surface Elevation. Focus 5.3: Magnetic Fields in Space.

6. The Perspective of Geologic Time.

The Age of Earth. Dating the Geologic Record. Radioactive Dating. Focus 6.1: Meteorite Impacts and Mass Extinctions. Focus 6.2: Dating Rocks, Minerals, and Other Materials Using Isotopes. Focus 6.3: Carbon Dating and Its Uses.

III: EARTH DYNAMICS.

7. Plate Tectonics.

Continental Drift: The Beginnings of the Idea. Plate Tectonics: A Unifying Theory. The Rock Record: Fossils, Climate, and Continents. Plates and Plate Boundaries. A Plate-Tectonic Link to Earthquakes and Volcanoes. Topography of the Lithosphere. What Drives Plate Motions? Plumes, Subducted Slabs, and the Workings of Place Tectonics. Plate Motions through Geologic Time. Ocean Basin Depths and Satellite Altimetry. Focus 7.1: The Nature of the Low-Velocity Zone. Focus 7.2: The San Andreas Fault, California. Focus 7.3: Hawaii: An Example of Intraplate Magmatism. Focus 7.4: Vector Notation for Plate Motion.

8. Deformation, Earthquakes, and Formation of Geologic Structures.

Crustal Deformation. Geologic Structures. Earthquakes. Plate Motions and Earthquakes. Intraplate Deformation. The Volcano Deformation Cycle. Focus 8.1: Calculation of Moment Magnitude. Focus 8.2: Prediction of the Haicheng Earthquake of 1975. Focus 8.3: The Loma Prieta Earthquake. Volcanic Deformation in Hawaii.

9. Making and Breaking Plates.

Rifts: Windows to the Mantle. Oceanic Rifting. Transform Margins. Continental Rifting. Focus 9.1: The East Pacific Rise and Mid-Atlantic Ridge. Focus 9.2: The Alpine Fault, New Zealand. Focus 9.3: The Salton Trough of California. Focus 9.4: Continental Rifting: The East African Rift.

10. Destroying Plates and Building Continents.

Convergent Plate Margins: Structure and Dynamics. Building Continents. Focus 10.1: The Andes and the Lesser Antilles: A Continental Arc and an Oceanic Arc. Focus 10.2: The Continental Collision between India and Asia and the Building of the Himalayas.

IV: SHAPING OF EARTH.

11. Earth's Water.

Properties of Water. Water in the Solar System. Water and Plate Tectonics. Water Cycles. Fresh Water. Our Need for Water. Focus 11.1: Water beyond Earth. Focus 11.2: Water Movement. Focus 11.3: Saltwater and Freshwater Isostasy.

12. The Formation of Sediments: Weathering.

Physical Weathering: The Disaggregation of Rocks into Sediment. Chemical Weathering: Oxidation, Hydration, and Hydrolysis of Minerals. Weathering and Plate-Tectonic Setting. The Role of Climate in Weathering. Focus 12.1: Acids and Minerals. Focus 12.2: Why Is the Ocean Salty?

13. Sedimentary Systems: Transportation and Deposition of Sediments.

Transportation of Sediments. Deposition of Sediments. Tectonic Control on Sedimentary Processes and Depositional Environments. Focus 13.1: Controls on Settling Velocities of Grains.

14. Geomorphology: The Study of Landforms.

Mass Wasting. Shaping the Surface: The Hydrologic Cycle. Fluvial Geomorphology. Glaciers. Deserts. Coasts. Volcanic Islands. Geomorphology at Passive and Active Continental Margins. Focus 14.1: Fractals and Scale Invariance in Geology. Focus 14.2: The Physics of Mass Wasting. Focus 14.3: Ice Ages.

V: EARTH AND ENVIRONMENT.

15. Geologic Hazards and the Environment.

Earthquakes: Where the Dangers Are. Volcanic Hazards. Landslides. Flooding. Coastal Erosion Problems. Pollution. The Greenhouse Effect and Global Warming. The Ozone Hole. Focus 15.1: A Comparison of Two Earthquakes: At a Subduction Zone and in a Plate Interior. Focus 15.2: The Eruption of Mount St. Helens. Focus 15.3: The Antarctic Ozone Hole.

16. Earth Resources.

Mineral Resources. Mineral Deposits. Fossil Fuels. Estimating the Time Until Nonrenewable Resources Will Run Out. Focus 16.1: Uranium Ore and Nuclear Energy. Focus 16.2: How Plate Tectonics Redistributes Mineral and Organic Resources. Focus 16.3: Resources from Space.

Appendix I: Conversion Tables.
Appendix II: Geologic Time Scale.
Appendix III: The Periodic Table of the Elements.
Appendix IV: Common Minerals and Their Properties.
Appendix V: Rock Types, Descriptions, and Examples.
Appendix VI: Earth Statistics.
Glossary.
Photo Credits.
Index.

Excerpts

Preface With this book, we hope to introduce readers to the world of physical geology and to share with them the excitement of exploring Earth and the processes that formed it. We hope that readers of this book will gain a better understanding of Earth and an increased awareness of our planet. Whey traveling by airplane, a reader will appreciate how mountains, rivers, and deserts were formed, and what governs their locations, shapes, and textures. A hiker will understand how multicolored pebbles in a stream formed and where they came from. Earthquakes, volcanic eruptions, tidal waves, and other geologic hazards will be viewed with a greater understanding of the processes that give rise to such events. We have taught the introductory geology and geophysics courses at the University of California at Los Angeles and the University of Durham for a cumulative total of forty years. Students have traveled with us on field trips to every continent. Because our special areas of study include not only geology, but also geophysics and geochemistry, we seized the opportunity to present an interdisciplinary approach to physical geology. We felt the need for a book that presents geology in the framework of plate tectonics with a strong emphasis on geologic processes. We feel strongly that this approach presents the field of geology in its full richness while making the subject both more interesting and easier to learn. We wrote this book for students with little or no scientific background. Toward this end, we have avoided unnecessary use of jargon, introducing geologic terms in context and only as needed. We describe geologic time using millions wand billions of years rather than using the traditional geological time scale, which we have found can cause unnecessary difficulty for students taking their first geology course. We have limited the use of mathematical expressions, but those that we have included serve to introduce students to a few of the powerful and concise tools geologists use to quantify the processes and characteristics of Earth. We think this book will give pleasure to students by increasing their awareness and understanding of their surroundings. Indeed, we hope that some will continue on to become geologists and share in the excitement that we have experienced working in this field. In any case, it has been our intention here to make the subject easy to learn and one of never-ending fascination. Organization of the Book After a brief introduction to the Earth as a system in Chapter 1, in which plate tectonics, climate, and time are all closely linked, the order of material presented in the book follows the evolution of Earth from its formation to the development of plate tectonics and present-day geology. Chapter 2 presents the formation of Earth and the elements and the partition of Earth into crust, mantle, and core. Throughout, we emphasize how scientists arrived at our present understanding of Earth's internal composition and processes. Students can then appreciate the origin of Earth's huge internal energy source and understand how that energy drives plate tectonics. In Chapters 3 and 4, we turn to the material of Earth itself and explore rocks and the minerals from which rocks are formed. Chapter 5 introduces the approaches that gave rise to our present understanding of Earth's interior and internal processes. These include measurements of seismic waves, gravity, and magnetism of Earth. It also provides the background for the development of the plate-tectonic theory. Chapter 6 then takes a closer look at geologic time--how it is measured and how we can appreciate the operation of processes at various different rates--many imperceptible over human lifetimes. Chapter 7 explores plate tectonics from its early roots in the theory of continental drift to our present-day understanding--including some of the outstanding problems which are still