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Introduction

Geology is the study of the earth. By default this means that geology is a vast, complex, and intricate topic. But “vast, intricate, and complex” does not necessarily mean difficult. Many folks interested in geology just don’t know where to start. Minerals? Rocks? Glaciers? Volcanoes? Fossils? Earthquakes? The sheer number of topics covered under the heading “geology” can be overwhelming.

Enter Geology For Dummies! The goal of this book is to break through the overwhelming array of geology information and provide a quick reference for key concepts in the study of the earth.

My hope is that you find this book both interesting and useful, whether you’ve purchased it to accompany a course you’re taking in school or to help you find answers to questions you have about the planet you live on.

About This Book

In Geology For Dummies, you can start anywhere. This book is written as an introduction to the most common topics in geology. Follow your interest from one topic to the next, or start at the beginning and read the chapters in order. I wrote the book in a style that allows you to open to any page and learn something. But if you want to start at the beginning, you’re introduced to the concepts in a logical and structured order that (I hope!) answers your questions almost as soon as you ask them.

Throughout the book you find cross-references to other chapters. I use them because it’s impossible to explore one topic in geology without touching on many others. The multiple cross-references weave together the different parts of geologic study into a complex whole.

Wherever possible, I include illustrations to accompany my explanations. Geology is all around you, so while you are busy reading this book and examining the illustrations, I encourage you to also look around and find real-world examples of the processes and features I describe. To this end, I have also included a color photo section in the middle of the book featuring vivid images that help bring the subject matter to life.

Foolish Assumptions

As I was writing this book, I had to make a few assumptions about you, the reader. I assume that you live on Earth and are familiar with rocks, streams, and weather (rain, wind, and sun). I also assume that you are familiar with a very basic geography of the earth, including the continents, oceans, and major mountain ranges.

I do not assume that you have any scientific background in chemistry, which you may find useful if you want to dig deeper into the details of rock formation and transformation. Similarly, when I discuss evolution I do not assume that you have any background in biology or anatomy (and none is needed to understand the concepts I present). If the subject of evolution interests you, you may find that your questions lead you to pick up other reference books on that topic.

If you find that your interest in geology is further fueled by this book, I recommend that you purchase an earth science or geology dictionary. Geology is full of terms with precise and informative meanings. With this kind of dictionary on hand, you’ll find you can easily interpret even the most befuddling geological explanations.

Icons Used in This Book

Throughout this book, I use icons to draw your attention to certain information:

The Tip icon indicates information that may be especially useful to you as you prepare for a geology exam or assignment or as you begin studying geology on your own.

This icon, which appears only rarely in this book, points out situations that may be dangerous.

Information highlighted with the Remember icon is foundational to understanding the concept being explained. Sometimes this icon indicates a definition or concise explanation. Other times it indicates information that will help you tie multiple concepts together.

This icon indicates that the information goes a little beyond the surface into some technical details. These details are not necessary for your broad understanding of the topic or concepts, but you may find them interesting and informative.

Beyond the Book

In addition to what you’re reading right now, this product also comes with a free access-anywhere Cheat Sheet that tells you about plate tectonics and the geologic timescale.. To get this Cheat Sheet, simply go to www.dummies.com and type Geology For Dummies Cheat Sheet in the Search box.

Where to Go from Here

You have most likely purchased this book with a question about geology already in mind. In that case, I encourage you to follow your interest. Use the table of contents or index to find where I answer your question, flip to that page, and get started!

If you don’t have a particular question in mind, here are a few of my favorite topics that will get you started on your study of Earth:

 Chapter 8, “Adding Up the Evidence for Plate Tectonics”: In this chapter, I tell you the story of how an early geologist, Alfred Wegener, began to think about plate movements. He collected evidence to support his ideas, but it took many years before the idea of plate tectonics was accepted by the scientific community. This chapter is a great introduction to how science really happens, as well as an overview of the foundational theory of modern geology.

 Chapter 12, “Water: Above and Below Ground”: If you want to get started by reading about something you can relate to, start with flowing water. Streams and rivers are the most common geologic processes on Earth. Regardless of where you live, you have probably witnessed the action of flowing water moving sediment or rocks. This chapter provides details from how water picks up and carries particles, to how rivers carve canyons and caves. It also covers the topic of groundwater, which is where most of the water you drink comes from.

 Chapter 18, “Time before Time Began: The Precambrian”: Long ago in Earth’s deep, dark, murky past lay the beginnings of life. This chapter describes the first few billion years of Earth’s existence, from its formation from a gaseous cloud, up to and including the earliest evidence for life — in the form of trace fossils called stromatolites.