Chapter 4: Rocks – Mineral Mixtures Section 1: The Rock Cycle

1. Chapter 4: Rocks – Mineral MixturesSection 1: The Rock Cycle

2. Chapter 4 Section 1The Rock Cycle The Rock Cycle • A rock is a naturally occurring solid mixture of one or more minerals or organic matter. • New rock forms from old rock material constantly. • The series of processes in which a rock forms, changes from one type to another, is destroyed, and forms again by geological processes is called the rock cycle.

3. Chapter 4 Section 1The Rock Cycle

4. **Show Brain Pop Video: Rock Cycle**

5. Chapter 4 Section 1The Rock Cycle The Value of Rock • Rock has been an important natural resource for as long as humans have existed. • Ancient and modern civilizations have used granite, limestone, marble sandstone, slate and other rocks as construction materials. • Rock is also an important ingredient in concrete and plaster, both of which are commonly used in construction.

6. Chapter 4 Section 1The Rock Cycle Processes That Shape the Earth • Certain geological processes make and destroy rock. • These processes shape the features of our planet. • These processes also influence the type of rock that is found in certain areas. Resources

7. Chapter 4 Section 1The Rock Cycle Processes That Shape the Earth, continued • The process in which water, wind, ice, and heat break down rock is calledweathering. • Weathering is important because it breaks down rock into fragments of which sedimentary rock is made.

8. Chapter 4 Section 1The Rock Cycle Processes That Shape the Earth, continued • The process by which wind, water, ice, or gravity transports soil and sediment from one location to another is callederosion. • The process in which sediment moved by erosion is dropped and comes to rest is calleddeposition.

9. Chapter 4 Section 1The Rock Cycle Processes That Shape the Earth, continued • Sedimentary rock can also form when buried sediment is squeezed by the weight of overlaying layers of sediment. • If the temperature and pressure are high enough, the rock can change into metamorphic rock. • If the rock gets hot enough to melt, this creates the magma that eventually cools to form igneous rock.

10. Chapter 4 Section 1The Rock Cycle Processes That Shape the Earth, continued • How the Cycle Continues Buried rock is exposed at the Earth’s surface by a combination of uplift and erosion. • Upliftis the movement within the Earth that causes rocks inside the Earth to be moved to the surface. • When uplifted rock reaches the Earth’s surface, weathering, erosion, and deposition begin.

11. Chapter 4 Section 1The Rock Cycle Illustrating the Rock Cycle • The rock cycle is the continual process by which new rock forms from old rock material. Round and Round It Goes • Rocks may follow various pathways in the rock cycle.

12. Chapter 4 Section 1The Rock Cycle Rock Classification • Rock can be three main classes based on how the rock is formed: • Igneous rock • Sedimentary rock • Metamorphic rock

13. Chapter 4 Section 1The Rock Cycle Rock Classification, continued • Each class of rock can be divided further, based on differences in the ways rocks form. • Igneous rock can be divided again based on whether the magma from which it forms cools on the Earth’s surface or below ground.

14. Chapter 4 Section 1The Rock Cycle Rock Classification, continued • Sedimentary and metamorphic rocks are also divided into smaller groups. • Scientists study rocks in detail using two important criteria: composition and texture.

15. Chapter 4 Section 1The Rock Cycle Rock Classification, continued • Composition is the chemical makeup of a rock. Composition can describe either the minerals or other materials in the rock. • Texture is the quality of a rock that is based on the sizes, shapes, and positions of the rock’s grains.