Earth’s Layered Structure

o Geosphere
- Solid Earth
- Extends from surface to the center of the planet
- Largest of Earth’s four spheres

o Solid Earth
- Based on compositional differences, it consists of the crust, mantle, and core
- Divisions of the outer portion are based on how materials behave

o Crust
- Earth’s relatively thin, rocky outer skin
- Continental crust
- Less dense, many rock types
- Granitic
- Oceanic crust
- Dense, basaltic rock

o Mantle
- Solid, rocky shell
- More than 82 percent of Earth’s volume
- Upper mantle
- Lithosphere – entire crust and uppermost mantle
- Asthenosphere – relatively soft layer
- Lower mantle
- Very hot, strengthens with depth

o Core
- Iron-nickel alloy
- Outer core
- Liquid layer
- Earth’s magnetic field
- Inner core
- Solid