Montgomery PrefaceABOUT THE COURSEEnvironmental geology is geology applied to living.
The environment is the sum of all the features and conditions surrounding an organism that may influence it. An individual’s physical environment encompasses rocks and soil, air and water, such factors as light and temperature, and other organisms. One’s social environment might include a network of family and friends, a particular political system, and a set of social customs that affect one’s behavior.
Geology is the study of the earth. Because the earth provides the basic physical environment in which we live, all of geology might in one sense be regarded as environmental geology. However, the term environmental geology is usually restricted to refer particularly to geology as it relates directly to human activities, and that is the focus of this book. Environmental geology is geology applied to living. We will examine how geologic processes and hazards influence human activities (and sometimes the reverse), the geologic aspects of pollution and waste-disposal problems, and several other topics.Why study environmental geology?
One reason for studying environmental geology might simply be curiosity about the way the earth works, about the how and why of natural phenomena. Another reason is that we are increasingly faced with environmental problems to be solved and decisions to be made, and in many cases, an understanding of one or more geologic processes is essential to finding an appropriate solution.
Of course, many environmental problems cannot be fully assessed and solved using geologic data alone. The problems vary widely in size and in complexity. In a specific instance, data from other branches of science (such as biology, chemistry, or ecology), as well as economics, politics, social priorities, and so on may have to be taken into account. Because a variety of considerations may influence the choice of a solution, there is frequently disagreement about which solution is “best.” Our personal choices will often depend strongly on our beliefs about which considerations are most important.ABOUT THE BOOKGeologic processes shape our natural environment.
An introductory text cannot explore all aspects of environmental concerns. Here, the emphasis is on the physical constraints imposed on human activities by the geologic processes that have shaped and are still shaping our natural environment. In a real sense, these are the most basic, inescapable constraints; we cannot, for instance, use a resource that is not there, or build a secure home or a safe dam on land that is fundamentally unstable. Geology, then, is a logical place to start in developing an understanding of many environmental issues. The principal aim of this book is to present the reader with a broad overview of environmental geology. Because geology does not exist in a vacuum, however, the text introduces related considerations from outside geology to clarify other ramifications of the subjects discussed. Likewise, the present does not exist in isolation from the past and future; occasionally, the text looks both at how the earth developed into its present condition and where matters seem to be moving for the future. It is hoped that this knowledge will provide the reader with a useful foundation for discussing and evaluating specific environmental issues, as well as for developing ideas about how the problems should be solved.Pedagogical features are designed for the student.
This text is intended for an introductory-level college course. It does not assume any prior exposure to geology or college-level mathematics or science courses. The metric system is used throughout, except where other units are conventional within a discipline. (For the convenience of students not yet “fluent” in metric units, a conversion table is included in appendix D, and in some cases, metric equivalents in English units are included within the text.)
Each chapter opens with an introduction that sets the stage for the material to follow. In the course of the chapter, important terms and concepts are identified by boldface type, and these terms are collected as “Terms to Remember” at the end of the chapter for quick review. Many chapters include actual case histories or specific examples. To these, each reader could no doubt add other examples from personal experience.
Each chapter concludes with review questions and exercises, which allow students to test their comprehension and apply their knowledge, followed by suggested readings and pertinent references.Readings and examples connect to life experiences.
Each chapter includes one or more boxed readings relating to the surrounding material. Some involve a situation, problem, or application that might be encountered in everyday life. Others offer additional case histories or relevant examples. The tone, in many cases, is light, but the underlying issues are nonetheless real. While some boxes were inspired by actual events, and include specific factual information, all of the characters quoted, and their interactions, are wholly fictitious. Students and instructors will find many additional readings on the text’s Online Learning Center.NetNotes link readers to timely, in-depth resources.
The listing of “NetNotes” at the end of each chapter offer modest collections of Internet sites that provide additional information and/or images relevant to the chapter content. An effort has been made to concentrate on sites with material at an appropriate level for the book’s intended audience and also on sites likely to be relatively stable in the very fluid world of the Internet (government agencies, educational institutions, or professional association sites). Though limited by space, this selection should help the novice user get started exploring the wealth of information available on the Internet and assist them in learning which sources are trustworthy.Unique appendices serve as key reference tools.
Relative to the length of time we have been on earth, humans have had a disproportionate impact on this planet. Appendix A explores the concept of geologic time and its measurement, and looks at the rates of geologic and other processes by way of putting human activities in temporal perspective. Appendix B gives an introduction to topographic and geologic maps, and satellite and other kinds of imagery, highlighting some new techniques for examining the earth. Appendix C provides short reference keys to aid in rock and mineral identification, and Appendix D includes units of measurement and conversion factors.
The Glossary collects definitions of boldface terms and select additional terms for quick reference.ORGANIZATIONCoverage begins with geologic processes, examines resources and consumption, and concludes with laws and land-use planning.
The book starts with some background information: a brief outline of earth’s development to the present, and a look at one major reason why environmental problems today are so pressing—the large and rapidly growing human population. This is followed by a short discussion of the basic materials of geology—rocks and minerals—and some of their physical properties, which introduces a number of basic terms and concepts that are used in later chapters.
The next several chapters treat individual processes in detail. Some of these are large-scale processes, which may involve motions and forces in the earth hundreds of kilometers below the surface, and may lead to dramatic, often-catastrophic events like earthquakes and volcanic eruptions. Other processes—such as the flow of rivers and glaciers or the blowing of the wind—occur only near the earth’s surface, altering the landscape and occasionally causing their own special problems. In some cases, geologic processes can be modified, deliberately or accidentally; in others, human activities must be adjusted to natural realities.
A subject of increasing current concern is the availability of resources. A series of five chapters deals with water resources, soil, minerals, and energy, the rates at which they are being consumed, probable amounts remaining, and projections of future availability and use. In the case of energy resources, we consider both those sources extensively used in the past, and new sources that may or may not successfully replace them in the future.
Increasing population and resource consumption lead to an increasing volume of waste to be disposed of; thoughtless or inappropriate waste disposal commonly creates increasing pollution. Three chapters examine the interrelated problems of air and water pollution and the strategies available for the disposal of various kinds of wastes. The introduction to this section presents some related concepts from the field of geo-medicine, linking geochemistry and health.
The final two chapters deal with a more diverse assortment of subjects. Environmental problems spawn laws intended to solve them; the environmental law chapter looks briefly at a sampling of laws and international agreements related to geologic matters discussed earlier in the book, and some of the problems with such laws and accords. The land-use planning and engineering geology chapter examines geologic constraints on construction schemes and the broader issue of trying to determine the optimum use(s) for particular parcels of land—matters that become more pressing as population growth pushes more people to live in marginal places.NEW TO THIS EDITIONThoroughly updated content
Much effort has been put into this seventh edition to ensure that the content is up-to-date and accurate. Input from reviewers has helped direct the revision and improve key content areas. Visit the Online Learning Center for a complete listing of specific changes to this edition. Improved photo program
Every photo in this edition has been carefully selected to provide the reader with significant detail to support the textual material. A number of new photos have been added and those that were retained for their subject value have been electronically enhanced for focus and clarity.More realistic art
Key pieces of art in this edition have been redrawn to offer a more accurate depiction, and in a style that is easier to comprehend and is more up-to-date. NEW! Digital Content Manager CD-ROM now available to instructors
This compilation of visual resources allows instructors to utilize all of the artwork from the text and other collections, in multiple formats, to create customized classroom presentations, visually based tests and/or quizzes, dynamic course website content, or attractive printed support materials. The CD includes over 100 animations portraying important geological concepts.
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2006 McGraw-Hill Higher Education