1. Earth Layers and Types of Crust
11/14/2018 5:14 AM
Earth Layers and Types of Crust
How have geologists learned about Earth’s interior structure and what causes convection currents in the mantle?
© 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

2. Earth’s Interior
Geologists have used two main types of evidence to learn about Earth’s interior.
1. Direct evidence from rock samples (drilled from deep inside Earth)
2. Indirect evidence from seismic waves (produced by earthquakes; speed gives clues to the material)
Three main layers of Earth vary greatly in size, composition, temperature and pressure. They are the crust, mantle and core.

3. The Layers of Earth CRUST CRUST LITHOSPHERE UPPER MANTLE MANTLE
ASTHENOSPHERE
LOWER MANTLE
OUTER CORE
CORE
INNER CORE

4. Layers of Earth

5. Two Types of Crust Oceanic Crust Rock Type Basalt Color Dark
Composition
Low Si, High Fe
Density
High
Average Thickness
6-7 km, avg.
Depth
(general)
Floats lower in the mantle – form basins that fill with water
Continental Crust
Granite
Light
High Si, Low Fe
Low
40 km, avg.
Floats higher in the mantle