Table of Contents Reading Rocks 4 Recycling Rocks 8 Inside the Earth 14 Igneous Rocks 21 Sedimentary Rocks 27 Metamorphic Rocks 34 Real Life Rock Stars 40 Glossary 46 Index 47 Show What You Know 47 Websites to Visit 47 About the Author 48
READING ROCKS In the late 1700s most scientists believed that planet Earth was very young no more than 6,000 years old They thought a great flood once shaped the land But one man thought differently James Hutton believed natural processes formed and continued to form the Earth over long periods of time He thought immense heat deep inside Earth pushed up the land to form new mountains 4 James Hutton 1726 1797
Over millions of years weather eroded the layers of soft and hard rock of Monument Valley a desert region on the Arizona-Utah border Over time wind rain and other forces wore down the Earth Some of this mud and sand became new rock and the cycle started again According to Hutton this cycle of building up and breaking down over and over took much longer than 6,000 years Old as the Hills Jack Hills in Western Australia is home to the oldest pieces of Earth ever found Bits of the mineral zircon 4 4 billion years old were discovered among the rocks AUSTRALIA 5
