Relative Dating

1. Life Science Mr. P Relative Dating

2. Law of Superposition • Layers of sedimentary rock are laid down in layers, with the oldest on the bottom and the newest layers on top.

3. This happens by…

4. Think of it like a building • When building a skyscraper, you start with the foundation and build the first floor…. • Then the second…. • Then the third…. • And so on…

5. Relative Dating • The relative age tells you how old something is compared to something else.

6. Think of it as… • Your older brother is 25 • Your younger brother is 8 • We can say you are between 8 and 25. • It gives us an approximation based on everything around it.

7. How it works… • Rock layers at the bottom are oldest • Rock layers at the top are younger • Anything that cuts through these layers (called intrusions) are the youngest

8. Index fossils • Index fossils are fossils that only existed a specific point in time and can be used as a reference

9. Lets try it…

10. A little tougher…

11. Its not very easy… • Just remember…the oldest layersare on the bottom and the youngest are on top.