1. Folds and Faults

2. What allows a rock to deform?

3. What allows a rock to deform?
Temperature
Pressure
….?

4. Granite vs. gypsum?

6. Salt Dome

7. What allows a rock to deform?
Temperature
Pressure
Rock type
….?

8. What allows a rock to deform?
Temperature
Pressure
Rock type
Time

10. Overturned fold
Syncline
Anticline
Where are
the oldest
rocks?

11. Plunging folds

12. Plunging folds – need ages

13. Where’s the syncline? Where’s the anticline?

14. Domes and basins…what is their origin?

15. Domes and basins result from plate tectonic
forces in continental interiors

16. Where’s the oldest material?

17. Domes and Basins

18. How do the ages vary? B

19. Brittle versus ductile deformation
Strain – change in shape
Stress - extension
Stress - extension

20. Brittle versus ductile deformation
Strain – change in shape
Stress - extension
Stress - extension
Folding Faulting

21. What causes ductile deformation?
Temperature
Pressure
Rock type
Time

22. What causes ductile deformation?
Temperature - high
Pressure - high
Rock type – low strength (i.e. gypsum)
Time - long

23. What causes brittle deformation?
Temperature
Pressure
Rock type
Time

24. What causes brittle deformation?
Temperature - low
Pressure – high
Rock type – high strength (i.e. granite)
Time - short

25. Fold types:
2-dimensional 3-dimensional
1) ? ?
2) ? ?
What kind of stress regime do these
folds represent?

26. Fold types:
2-dimensional 3-dimensional
1) Anticlines Domes
2) Synclines Basins
What kind of stress regime do these
folds represent? - Compressional

27. Brittle versus ductile deformation
Strain – change in shape
Stress - extension
Stress - extension
Folding Faulting

28. Reverse
Fault
Thrust
Fault

29. Compressional Setting
Reverse
Fault
Thrust
Fault

31. Extensional Setting

32. Compression or Extension?

33. What is the age progression? What kind of fault does this have to be?
Extension or compression?
ground surface
Cap rock

34. Normal Fault
Layers Repeat
Extension 5 4 3 4 3 2 1
Cap rock

35. What is the age progression? What kind of fault does this have to be?
Extension or compression?
ground surface

36. Reverse Fault
Layer Skipped
Compression 6 5 4 2 1

38. Strike-slip fault – horizontal displacement only

39. What is the offset direction?

40. What is the offset direction?
Left-lateral Right-lateral

41. San Andreas
Fault

43. Loch Ness
Is the Loch Ness Monster a Plesiosaur?

44. Loch Ness
Great Glen Fault
(strike-slip)

45. Three fault types:
Fault Stress regime Motion (V/H)?
1) ? ? ?
2) ? ? ?
3) ? ? ?

46. Three fault types:
Fault Stress regime Motion (V/H)?
1) Normal Extension Vertical
2) Reverse Compression Vertical
(Thrust)
3) Strike-slip Bi-directional Horizontal

47. What causes
this texture?

50. What causes
this texture?

51. Expansion

52. What causes
this texture?

53. Joints – 3 common formation mechanisms
Joint type Cause
1) ? ?
2) ? ?
3) ? ?

54. Joints – 3 common formation mechanisms
Joint type Cause
1) Columnar Contraction
2) Sheeting Expansion
3) Fault zone Prior faulting

55. Crustal Deformation –
Folding
Faulting
Jointing
Give information
about stresses
acting on the rock