CHAPTER 8 Earth’s History

Geology Erosion The study of the structure of planet Earth and of the forces that make and shape Earth When running water, ice or wind break down rocks and carry them away

3 Main Types of Rocks Igneous Rocks Form when molten material from beneath Earth’s surface cools and hardens The Latin root ignis means fire Table Talk: What other words can you think of that start with ign?

Sedimentary Rock Made of sediments that have been deposited and then pressed together to form solid rock. May contain the remains of plants or animals Table Talk: Why are most fossils found in sedimentary rock? sandstone Grand Canyon

Metamorphic Rock Forms when an existing rock is changed by heat, pressure, or chemical reactions deep underground Notice the distinct banding. gneiss slate serpentine See Brain Pop, “Types of Rocks”

The Rock CycleForces inside Earth and at its surface produce a cycle that builds, changes, and destroys rocks. A rock is never “just a rock.”

Pathways of the rock cycle Volcanic activity – Magma – Lava Erosion – Wearing away Deposition – Depositing (dropping off) Heat and Pressure Melting Active Art code cfp-1056 END See Brain Pop, “The Rock Cycle”