1. Chapter 4 Lesson 3 The Crust
Earth Science Unit 1
Chapter 4
Lesson 3
The Crust

2. The Crust The thin, hard outer layer of the Earth
It complex and varied because of the activity of the action of the mantle underneath
The Earth’s thinnest layer
The depth varies based on individual rocks beneath it

3. Kinds of Crust
Continental crust- The crust on which the continents rest
Has a more complex structure than the oceanic crust

4. Regions of The Continental Crust
1. Shields
Made of crystalline rocks
Ancient formations
Platforms – eroded shields that create vast planes
Examples: high plateaus in Africa and Asia

5. Regions of The Continental Crust
2. Mobile belts- folded rocks forming new mountians
Examples- Alps, Himalayas, Andes

6. Regions of The Continental Crust
3. Sedimentary basins- broad, deep depressions filled with sedimentary rocks
Form in shallow seas

7. Oceanic Crust The crust beneath the oceans
Basalt is the primary rock in this area
Thinner and denser than the continental crust
Consists of three layers

8. Top Layer Made of mud, sand, or other sediments
Can be up to 1 km thick

9. Second Layer
Can be 1 km thick
Made mostly of basalt

10. Third Layer
About 5 km thick
Made of gabbro