1. Forces that cause deformation
Ductile
Brittle

2. Behaviour of Rocks to Stress & Strain
Stress - a force per unit area at a particular point.
Strain - the change in size (volume) or shape, or both, while an object is undergoing stress.
Behaviour of rocks with increasing stress and strain.
Elastic behaviour occurs along the straight line portions (blue)
At stresses greater than the elastic limit (red points) the rock will either deform as a ductile material or break, as shown in the deformed rock cylinders.

3. Brittle: Faults

4. Ductile: Folds

5. Components of a fold Axis/Nose: most sharply curved part
• Limb: sides of a fold

6. Kinds of fold sets

7. ANOTHER TYPE OF FOLDS

8. Folded Rock Before Erosion

9. Folded Rock After Erosion
Eroded Anticline, older rocks in center. Syncline is opposite.

10. 3-D: Dome and Basin

11. UNCONFORMITY
A surface (or contact) represents a gap in the geologic record, with the rock unit immediately above the contact being considerablely younger than the rock beneath
Most unconformities are burried erosion surfaces.
3 types

12. Disconformity
An unconformity between parallel layers of sedimentary rocks which represents a period of erosion or non-deposition

13. Angular unconformity
An unconformity where horizontally parallel strata of sedimentary rock are deposited on tilted and eroded layers, producing an angular discordance with the overlying horizontal layers. The whole sequence may later be deformed and tilted by further orogenic activity

14. Angular unconformity
Angular unconformity

15. Nonconformity
A nonconformity exists between sedimentary rocks and metamorphic or igneous rocks when the sedimentary rock lies above and was deposited on the pre-existing and eroded metamorphic or igneous rock

16. Nonconformity

17. Measuring Attitude of Rocks
Dip - Angle of bed with the horizontal
Strike - Bearing (compass direction) of line of intersection between horizontal plane and the inclined bed.
Dip Direction – is the compass direction in which the angle of dip is measured.
Attitude of planar structures (bedding, faults, joints, foliations, etc.) is often depicted by the reading of strike and dip, or dip direction and dip.