Essentials Of Geology - 4th Edition - ESSENTIALS OF GEOLOGY FOURTH EDITION Stephen Marshak Essentials of Geology F O U R T H ED I T I O N Essentials of

Essentials Of Geology - 4th Edition - ESSENTIALS OF GEOLOGY...

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Unformatted text preview: ESSENTIALS OF GEOLOGY FOURTH EDITION Stephen Marshak Essentials of Geology F O U R T H ED I T I O N Essentials of Geology F OURT H ED I T ION Stephen Marshak UNIVERSIT Y OF ILLINOIS W . W . N O R T O N & C O M PA N Y N E W YO R K L O N D O N W. W. Norton & Company has been independent since its founding in 1923, when William Warder Norton and Mary D. Herter Norton first published lectures delivered at the People’s Institute, the adult education division of New York City’s Cooper Union. The firm soon expanded its program beyond the Institute, publishing books by celebrated academics from America and abroad. By mid-century, the two major pillars of Norton’s publishing program—trade books and college texts—were firmly established. In the 1950s, the Norton family transferred control of the company to its employees, and today—with a staff of four hundred and a comparable number of trade, college, and professional titles published each year—W. W. Norton & Company stands as the largest and oldest publishing house owned wholly by its employees. Copyright © 2013, 2009, 2007, 2004 by W. W. Norton & Company, Inc. All rights reserved Printed in the United States of America Fourth Edition Illustrations by Precision Graphics Composition by CodeMantra, Inc. Manufacturing by Courier—Kendallville, IN The text of this book is set in Adobe Caslon, with display in Conduit, Din, Marbrook BQ , and Univers. Editor: Eric Svendsen Senior project editors: Thomas Foley and Lory Frenkel Production manager: Benjamin Reynolds Copy editor: Jennifer Harris Managing editor, College: Marian Johnson Book design: Lissi Sigillo Art director: Rubina Yeh Media editor: Rob Bellinger Digital media editorial assistant, sciences: Paula Iborra Associate supplements editor: Callinda Taylor Marketing manager, physical sciences: Stacy Loyal Photography director: Trish Marx Editorial assistants: Hannah Bachman and Alicia González-Gross 978-0-393-91939-4 W. W. Norton & Company, Inc., 500 Fifth Avenue, New York, NY 10110 wwnorton.com W. W. Norton & Company Ltd., Castle House, 75/76 Wells Street, London W1T 3QT 1234567890 Cover photo: Wave-carved granite cliffs along the Côte Sauvage (“Wild Coast”), on the south side of Brittany, France (Lat 47°30’36.11”N, Long 3°9’1.17”W) D E D I C AT I O N To Kathy, David, Emma, and Michelle Brief Contents Preface xvii Prelude And Just What Is Geology? 1 Chapter 1 The Earth in Context 9 Chapter 2 The Way the Earth Works: Plate Tectonics 35 Chapter 3 Patterns in Nature: Minerals 71 Interlude A Rock Groups 88 Chapter 4 Up from the Inferno: Magma and Igneous Rocks 97 Chapter 5 The Wrath of Vulcan: Volcanic Eruptions 119 Interlude B A Surface Veneer: Sediments and Soils 148 Chapter 6 Pages of Earth’s Past: Sedimentary Rocks 163 Chapter 7 Metamorphism: A Process of Change 189 Interlude C The Rock Cycle 210 Chapter 8 A Violent Pulse: Earthquakes 217 Interlude D The Earth’s Interior Revisited: Insights from Geophysics 252 Chapter 9 Crags, Cracks, and Crumples: Crustal Deformation and Mountain Building 265 Interlude E Memories of Past Life: Fossils and Evolution 292 Chapter 10 Deep Time: How Old Is Old? 305 Chapter 11 A Biography of Earth 329 Chapter 12 Riches in Rock: Energy and Mineral Resources 353 Interlude F An Introduction to Landscapes and the Hydrologic Cycle 386 Chapter 13 Unsafe Ground: Landslides and Other Mass Movements 397 Chapter 14 Streams and Floods: The Geology of Running Water 417 Chapter 15 Restless Realm: Oceans and Coasts 445 Chapter 16 A Hidden Reserve: Groundwater 473 Chapter 17 Dry Regions: The Geology of Deserts 497 Chapter 18 Amazing Ice: Glaciers and Ice Ages 515 Chapter 19 Global Change in the Earth System 545 Metric Conversion Chart The Periodic Table of Elements Glossary G-1 Credits C-1 Index I-1 vi Contents Preface xvii See for Yourself—Using Google EarthTM xix PRELUDE And Just What Is Geology? P.1 P.2 P.3 1 In Search of Ideas 1 The Nature of Geology 2 Themes of This Book 3 BOX P.1 CONSIDER THIS . . . Heat and Heat Transfer 4 BOX P.2 CONSIDER THIS . . . The Scientific Method 6 CHAPTER 1 The Earth in Context 1.1 1.2 1.3 9 Introduction 9 An Image of Our Universe 10 Forming the Universe 13 BOX 1.1 CONSIDER THIS . . . The Nature of Matter 1.4 16 We Are All Made of Stardust 17 BOX 1.2 CONSIDER THIS . . . Meteors and Meteorites 1.5 20 Welcome to the Neighborhood 21 GEOLOGY AT A GL ANCE Forming the Planets and the Earth-Moon System 22–23 1.6 Looking Inward—Introducing the Earth’s Interior 26 1.7 What Are the Layers Made Of? 29 Chapter 1 Review 32 See for Yourself A: Earth and Sky 33 CHAPTER 2 The Way the Earth Works: Plate Tectonics 2.1 2.2 2.3 35 Introduction 35 Wegener’s Evidence for Continental Drift 36 Paleomagnetism and the Proof of Continental Drift 39 vii 2.4 2.5 2.6 2.7 2.8 2.9 2.10 2.11 2.12 The Discovery of Sea-Floor Spreading 43 Evidence for Sea-Floor Spreading 45 What Do We Mean by Plate Tectonics? 49 Divergent Plate Boundaries and Sea-Floor Spreading 52 Convergent Plate Boundaries and Subduction 54 Transform Plate Boundaries 57 Special Locations in the Plate Mosaic 57 How Do Plate Boundaries Form and Die? 61 What Drives Plate Motion, and How Fast Do Plates Move? 63 GEOLOGY AT A GL ANCE Theory of Plate Tectonics 64–65 Chapter 2 Review 68 See for Yourself B: Plate Tectonics 69 CHAPTER 3 Patterns in Nature: Minerals 3.1 3.2 3.3 71 Introduction 71 What Is a Mineral? 72 Beauty in Patterns: Crystals and Their Structure 73 BOX 3.1 CONSIDER THIS . . . Some Basic Concepts from Chemistry 3.4 3.5 3.6 74 How Can You Tell One Mineral from Another? 77 Organizing Our Knowledge: Mineral Classification 81 Something Precious—Gems! 83 BOX 3.2 CONSIDER THIS . . . Where Do Diamonds Come From? 84 Chapter 3 Review 86 See for Yourself C: Minerals 87 INTERLUDE A Rock Groups A.1 A.2 A.3 A.4 88 Introduction 89 What Is Rock? 89 The Basis of Rock Classification 89 Studying Rock 91 CHAPTER 4 Up from the Inferno: Magma and Igneous Rocks 4.1 4.2 4.3 4.4 viii 97 Introduction 97 Why Does Magma Form, and What Is It Made Of? 99 Movement and Solidification of Molten Rock 102 How Do Extrusive and Intrusive Environments Differ? 104 BOX 4.1 CONSIDER THIS . . . Bowen’s Reaction Series 4.5 105 How Do You Describe an Igneous Rock? 109 GEOLOGY AT A GL ANCE Formation of Igneous Rocks 112 4.6 Plate-Tectonic Context of Igneous Activity 113 Chapter 4 Review 116 See for Yourself D: Igneous Rocks 117 CHAPTER 5 The Wrath of Vulcan: Volcanic Eruptions 5.1 5.2 5.3 119 Introduction 119 The Products of Volcanic Eruptions 120 The Structure and Eruptive Style of Volcanoes 124 BOX 5.1 CONSIDER THIS . . . Volcanic Explosions to Remember 130 GEOLOGY AT A GL ANCE Volcanoes 132–133 5.4 Relation of Volcanism to Plate Tectonics 134 5.5 Beware: Volcanoes Are Hazards! 137 5.6 Protection from Vulcan’s Wrath 141 5.7 Effect of Volcanoes on Climate and Civilization 143 5.8 Volcanoes on Other Planets 144 Chapter 5 Review 146 See for Yourself E: Volcanoes 147 INTERLUDE B A Surface Veneer: Sediments and Soils B.1 B.2 148 Introduction 149 Weathering: Forming Sediment 150 GEOLOGY AT A GL ANCE Weathering, Sediment, and Soil Production B.3 154–155 Soil 157 CHAPTER 6 Pages of Earth’s Past: Sedimentary Rocks 6.1 6.2 6.3 6.4 163 Introduction 163 Classes of Sedimentary Rocks 164 Sedimentary Structures 173 How Do We Recognize Depositional Environments? 177 ix GEOLOGY AT A GL ANCE The Formation of Sedimentary Rocks 180–181 6.5 Sedimentary Basins 184 Chapter 6 Review 186 See for Yourself F: Sedimentary Rocks 187 CHAPTER 7 Metamorphism: A Process of Change 7.1 7.2 7.3 7.4 189 Introduction 189 Consequences and Causes of Metamorphism 190 Types of Metamorphic Rocks 193 Where Does Metamorphism Occur? 198 BOX 7.1 CONSIDER THIS . . . Metamorphic Facies 200 BOX 7.2 CONSIDER THIS . . . Pottery Making—An Analog for Thermal Metamorphism 202 GEOLOGY AT A GL ANCE Environments of Metamorphism 204–205 Chapter 7 Review 208 See for Yourself G: Metamorphic Rocks 209 INTERLUDE C The Rock Cycle C.1 C.2 C.3 210 Introduction 211 A Case Study of the Rock Cycle 212 What Drives the Rock Cycle in the Earth System? 212 GEOLOGY AT A GL ANCE Rock-Forming Environments and the Rock Cycle CHAPTER 8 A Violent Pulse: Earthquakes 8.1 8.2 217 Introduction 217 What Causes Earthquakes? 218 GEOLOGY AT A GL ANCE Faulting in the Crust 8.3 8.4 8.5 8.6 x 222–223 Seismic Waves 224 How Do We Measure and Locate Earthquakes? 225 Defining the “Size” of Earthquakes 228 Where and Why Do Earthquakes Occur? 231 214–215 BOX 8.1 CONSIDER THIS . . . The 2010 Haiti Catastrophe 234 8.7 How Do Earthquakes Cause Damage? 236 8.8 Can We Predict the “Big One”? 245 8.9 Earthquake Engineering and Zoning 247 Chapter 8 Review 250 See for Yourself H: Earthquakes 251 INTERLUDE D The Earth’s Interior Revisited: Insights from Geophysics D.1 D.2 D.3 D.4 D.5 D.6 252 Introduction 253 Setting the Stage for Seismic Study of the Interior 253 The Movement of Seismic Waves through the Earth 254 Seismic Study of Earth’s Interior 255 Earth’s Gravity 260 Earth’s Magnetic Field, Revisited 262 CHAPTER 9 Crags, Cracks, and Crumples: Crustal Deformation and Mountain Building 265 9.1 9.2 9.3 Introduction 265 Rock Deformation 266 Brittle Structures 270 BOX 9.1 CONSIDER THIS . . . Describing the Orientation of Geologic Structures 9.4 9.5 272 Folds and Foliations 275 Mountain Building 279 GEOLOGY AT A GL ANCE The Collision of India with Asia 282–283 9.6 Mountain Topography 285 9.7 Basins and Domes in Cratons 287 Chapter 9 Review 290 See for Yourself I: Geologic Structures 291 INTERLUDE E Memories of Past Life: Fossils and Evolution E.1 E.2 E.3 The Discovery of Fossils 293 Fossilization 293 Taxonomy and Identification 297 E.4 E.5 292 The Fossil Record 299 Evolution and Extinction 300 xi CHAPTER 10 Deep Time: How Old Is Old? 10.1 10.2 10.3 10.4 10.5 10.6 305 Introduction 305 The Concept of Geologic Time 306 Geologic Principles for Defining Relative Age 306 Unconformities: Gaps in the Record 309 Stratigraphic Formations and Their Correlation 312 The Geologic Column 315 GEOLOGY AT A GL ANCE The Record in Rocks: Reconstructing Geologic History 318–319 10.7 How Do We Determine Numerical Age? 320 10.8 Numerical Age and Geologic Time 323 Chapter 10 Review 326 See for Yourself J: Geologic Time 327 CHAPTER 11 A Biography of Earth 329 11.1 11.2 11.3 11.4 11.5 11.6 Introduction 329 The Hadean Eon: Before the Rock Record 330 The Archean Eon: Birth of the Continents and Life 331 The Proterozoic: The Earth in Transition 333 The Paleozoic Era: Continents Reassemble and Life Gets Complex 336 The Mesozoic Era: When Dinosaurs Ruled 341 11.7 The Cenozoic Era: The Modern World Comes to Be 345 GEOLOGY AT A GL ANCE The Evolution of Earth 346–347 Chapter 11 Review 350 See for Yourself K: Earth History 351 CHAPTER 12 Riches in Rock: Energy and Mineral Resources 12.1 12.2 12.3 12.4 Introduction 353 Sources of Energy in the Earth System 354 Oil and Gas 355 Oil Exploration and Production 357 BOX 12.1 CONSIDER THIS . . . Types of Oil and Gas Traps 12.5 12.6 xii 359 Unconventional Reserves of Hydrocarbons 362 Coal: Energy from the Swamps of the Past 362 353 BOX 12.2 CONSIDER THIS . . . The Marcellus Gas Play 12.7 12.8 12.9 363 Nuclear Power 367 Other Energy Sources 369 Energy Choices, Energy Problems 371 BOX 12.3 CONSIDER THIS . . . Offshore Drilling and the Deepwater Horizon Disaster 374 12.10 Introducing Mineral Resources 375 12.11 Metals and Ores 375 12.12 Ore-Mineral Exploration and Production 379 12.13 Nonmetallic Mineral Resources 380 12.14 Global Mineral Needs 382 Chapter 12 Review 384 See for Yourself L: Energy and Mineral Resources 385 INTERLUDE F An Introduction to Landscapes and the Hydrologic Cycle F.1 F.2 F.3 386 Introduction 387 Shaping the Earth’s Surface 387 Factors Controlling Landscape Development 388 BOX F.1 CONSIDER THIS . . . Topographic Maps and Profiles F.4 F.5 389 The Hydrologic Cycle 390 Landscapes of Other Planets 391 GEOLOGY AT A GL ANCE The Hydrologic Cycle 392–393 BOX F.2 CONSIDER THIS . . . Water on Mars? 395 CHAPTER 13 Unsafe Ground: Landslides and Other Mass Movements 13.1 13.2 397 Introduction 397 Types of Mass Movement 398 BOX 13.1 CONSIDER THIS . . . What Goes Up Must Come Down 13.3 402 Why Do Mass Movements Occur? 405 xiii GEOLOGY AT A GL ANCE Mass Movement 408–409 13.4 How Can We Protect Against Mass-Movement Disasters? 411 Chapter 13 Review 414 See for Yourself M: Mass Movements 415 CHAPTER 14 Streams and Floods: The Geology of Running Water 14.1 14.2 14.3 14.4 14.5 14.6 14.7 14.8 Introduction 417 Draining the Land 418 Describing Flow in Streams: Discharge and Turbulence 421 The Work of Running Water 422 How Do Streams Change Along Their Length? 424 Streams and Their Deposits in the Landscape 425 The Evolution of Drainage 431 Raging Waters 433 GEOLOGY AT A GL ANCE River Systems 438–439 14.9 Vanishing Rivers 440 Chapter 14 Review 442 See for Yourself N: Stream Landscapes 443 CHAPTER 15 Restless Realm: Oceans and Coasts 15.1 15.2 15.3 445 Introduction 445 Landscapes Beneath the Sea 445 Ocean Water and Currents 448 BOX 15.1 CONSIDER THIS . . . The Coriolis Effect 15.4 15.5 15.6 15.7 15.8 450 Tides 451 Wave Action 452 Where Land Meets Sea: Coastal Landforms 454 Causes of Coastal Variability 460 Coastal Problems and Solutions 461 GEOLOGY AT A GL ANCE Oceans and Coasts 462–463 Chapter 15 Review 470 See for Yourself O: Oceans and Coastlines 471 xiv 417 CHAPTER 16 A Hidden Reserve: Groundwater 16.1 16.2 16.3 473 Introduction 473 Where Does Groundwater Reside? 474 Groundwater Flow 477 BOX 16.1 CONSIDER THIS . . . Darcy’s Law for Groundwater Flow 16.4 16.5 16.6 16.7 479 Tapping Groundwater Supplies 480 Hot Springs and Geysers 481 Groundwater Problems 484 Caves and Karst 487 GEOLOGY AT A GL ANCE Caves and Karst Landscapes 490–491 Chapter 16 Review 494 See for Yourself P: Groundwater and Karst Landscapes 495 CHAPTER 17 Dry Regions: The Geology of Deserts 17.1 17.2 17.3 17.4 17.5 17.6 497 Introduction 497 The Nature and Locations of Deserts 498 Weathering and Erosional Processes in Deserts 500 Deposition in Deserts 503 Desert Landscapes and Life 504 Desert Problems 508 GEOLOGY AT A GL ANCE The Desert Realm 510–511 Chapter 17 Review 512 See for Yourself Q: Desert Landscapes 513 CHAPTER 18 Amazing Ice: Glaciers and Ice Ages 18.1 18.2 515 Introduction 515 Ice and the Nature of Glaciers 516 BOX 18.1 CONSIDER THIS . . . Polar Ice Caps on Mars 18.3 18.4 519 Carving and Carrying by Ice 523 Deposition Associated with Glaciation 526 xv GEOLOGY AT A GL ANCE Glaciers and Glacial Landforms 530–531 18.5 Other Consequences of Continental Glaciation 532 18.6 The Pleistocene Ice Age 534 18.7 The Causes of Ice Ages 538 Chapter 18 Review 542 See for Yourself R: Glacial Landscapes 543 CHAPTER 19 Global Change in the Earth System 19.1 19.2 19.3 545 Introduction 545 Unidirectional Changes 546 Physical Cycles 547 GEOLOGY AT A GL ANCE The Earth System 19.4 19.5 548–549 Biogeochemical Cycles 550 Global Climate Change 551 BOX 19.1 CONSIDER THIS . . . The Role of Greenhouse Gases 552 19.6 Human Impact on the Earth System 557 19.7 The Future of the Earth 564 Chapter 19 Review 566 See for Yourself S: Global Change 567 Metric Conversion Chart The Periodic Table of Elements xvi Preface Narrative Themes Why do earthquakes, volcanoes, floods, and landslides happen? What causes mountains to rise? How do beautiful landscapes develop? Do climate and life change through time? When did the Earth form and by what process? Where do we dig to find valuable metals and where do we drill to find oil? Does sea level change? Can continents move? The study of geology addresses these important questions and many more. But from the birth of the discipline in the late 18th century until the mid-20th century, geologists considered each question largely in isolation, without pondering its relation to the others. This approach changed, beginning in the 1960s, in response to the formulation of two paradigm-shifting” ideas that have unified thinking about the Earth and its features. The first idea, called the theory of plate tectonics, states that the Earth’s outer shell consists of discrete plates that slowly move relative to each other so that the map of our planet continuously changes. Plate interactions cause earthquakes and volcanoes, build mountains, provide gases that make up the atmosphere, and affect the distribution of life on Earth. The second idea, called the Earth System concept, emphasizes that our planet’s water, land, atmosphere, and living inhabitants are dynamically interconnected. In the Earth System, materials constantly cycle among various living and nonliving reservoirs on, above, and within the planet. Thus, we have come to realize that the history of life is intimately linked to the history of the physical Earth. Essentials of Geology, Fourth Edition, is an introduction to the study of our planet that employs the theory of plate tectonics and the concept of the Earth System throughout to weave together a number of narrative themes, including the following: 1. The solid Earth, the oceans, the atmosphere, and life interact in complex ways, yielding a planet that is unique in the Solar System. 2. Most geologic processes reflect the interactions among plates. 3. The Earth is a planet, formed like other planets from dust and gas. But, in contrast to other planets, the Earth is a dynamic place on which new geologic features continue to form and old ones continue to be destroyed. 4. The Earth is very old—about 4.57 billion years have passed since its birth. During this time, the surface, subsurface, and atmosphere of the planet have changed, and life has evolved. 5. Internal processes (driven by Earth’s internal heat) and external processes (driven by heat from the Sun) interact at the Earth’s surface to produce complex landscapes. 6. Geologic knowledge can help society understand natural hazards such as earthquakes, volcanoes, landslides, and floods, and in some cases can reduce the danger that these hazards pose. 7. Energy and mineral resources come from the Earth and are formed by geologic phenomena. Geologic study can help locate these resources and mitigate the consequences of their use. 8. Physical features of the Earth are linked to life processes, and vice versa. 9. Science comes from observation; people make scientific discoveries. 10. Geology utilizes ideas from physics, chemistry, and biology, so the study of geology provides an excellent means to improve science literacy. These narrative themes serve as the take-home message of this book, a message that students should remember long after they finish their introductory geology course. In effect, they provide a mental framework on which students can organize and connect ideas, and develop a modern, coherent image of our planet. Pedagogical Approach Students learn best from textbooks when they can actively engage with a combination of narrative text and narrative art. Some students respond more to the words, which help them to organize information, provide answers to questions, fill in the essential steps that link ideas together, and develop a personal context for understanding information. Some students respond more to narrative art—art designed to tell a story— for visual images help students comprehend and remember processes. And some respond to question-and-answer-based xvii Preface xviii active learning, an approach where students can in effect “practice” their knowledge in real time. Essentials of Geology, Fourth Edition provides all three of these learning tools. The text has been crafted to be engaging and to carry students forward in a narrative form, the art has been configured to tell a story, the chapters are laid out to help students internalize key principles, and the online activities have been designed to both engage students and provide active feedback. For example, Did You Ever Wonder panels prompt students to connect new information to their existing knowledge base by asking geology-related questions that they have probably already thought about. Take...
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