Relative Dating

1. Relative Dating

3. Relative Dating • This is a technique geologists use to place events in the order they occurred without using “absolute” ages. • R.D. says one thing is older or younger than something else, but does not give its actual age.

4. The Principle of Original Horizontality • T.P.O.H. says that sediments that form layers tend to be deposited horizontally

5. The Principle of Original Horizontality • TPOH says that sediments that form layers tend to be deposited horizontally

6. Principle of Superposition • If these layers continue to be laid down for millions of years without being disturbed then the oldest material must be at the bottom. • This is the P.o.S.

7. An Intrusion • When magma is forced up through rock layers above it.

8. An Intrusion • When magma is forced up through rock layers above it. • If the intrusion cuts across existing layers it is called a dike.

9. An Intrusion • When magma is forced up through rock layers above it. • If the intrusion runs parallel to the layers it is called a sill.

10. Fold • If sediment layers are bent up or down they are known as a fold.

11. Fault • Sediment layers might break instead of bending. Then this is called a fault.

12. The Principle of Cross-cutting • The P.o.C.C. states that intrusions and faults must be younger than the rock they cut through.

13. How did life get started on Earth? Maybe this way

14. Or, maybe like this... Seeds of Life Came From Space

15. The End