Folds & Faults

1. Folds & Faults

2. Words to know • Rock Strata • These are rock layers under the surface. • They are normally flat (horizontal) when deposited. • Fold • Fault • Stratigrapher • Geologist that studies rock layers. • Rebound theory

3. Normal Strata • Flat - aka Horizontal

4. Irregular strata • Sometimes rock strata is squeezed and “folded” • A fold is when the strata is bent.

7. Folded Strata • How does flat strata become folded? • Compressional forces bend the strata. • Like paper would respond if you push the sides together

8. Large scale folding

9. Faulted Strata • What causes strata to fault or break? • Fault is when the strata breaks from outside forces.

11. Rebounding theory • Think of a rubber band. • If I hold it out it will be flat. • But if I add weight it will dip down • But when I take the weight off it goes back. • The Earth does the same!

12. Measuring Folds & Faults • Strike • The strike is a line the shows the directions on the surface of the fault. • Dip • The angle the plane goes into the ground.

13. Types of faults • 1.)Normal 2.)Reverse (thrust) 3.)Strike Slip • Faults are caused from forces within the Earth pushing or pulling rock strata.

14. How to ID Faults • Head Wall • Foot Wall • Normal Fault • Head wall moves down • Reverse Fault • Head wall moves up ? ?

16. Strike Slip