1. Relative Age of Rocks
Chapter 9
Section 2
Pgs

2. Principle of Superposition
Oldest rocks on the bottom and become younger going towards the top
Sediments form horizontal beds and creates layers
Formation of mountains can cause layers to go upside down 2

3. Relative Age
Something is its age in comparison to the ages of other things
Determine age by examining their places in a sequence
Fossils can also help determine age of rocks 3

4. Unconformities Incomplete rock layers missing or gaps in rock sequence
Angular – layers are tilted upward by forces, erosion occurs, new layers formed on top
Disconformity – gap in layers or when no new deposits form a new layer
Nonconformity – metamorphic or igneous rocks are uplifted and eroded 4

5. Questions What is the Principle of Superposition?
When a mountain forms what happens to the rock layer?
What is relative age?
How do scientists determine the age of rocks?
What are the three types of unconformities? 5