1. DEFINITION
MECHANICAL PRINCIPLE: deals with the physical properties of rocks and the significance of these properties in rock deformation.

2. DEFINITION
FOLDS: are wavy undulations, bend, flexure or wrinkle in rocks.

3. Fold

4. Fold

5. DEFINITION
FAULTS: are ruptures along which the opposite walls have moved past each other.

6. Fault

7. Fault

8. DEFINITION
JOINTS: a break in a rock mass where there has been no relative movement of rock on opposite sides of the break.

9. Joint

10. Joint

11. DEFINITION
UNCONFORMITY: an unconformity is a surface of erosion or non-deposition – that separates younger strata from older.

12. Unconformity

13. Unconformity

14. DEFINITION
CLEAVAGE: is the property of rocks whereby they break along parallel surfaces of secondary origin.
SCHISTOSITY: is a term applied to the variety of rock cleavage found in rocks that are sufficiently recrystallized to be called schist or gneiss.

15. DEFINITION
CLEAVAGE: is the property of rocks whereby they break along parallel surfaces of secondary origin.
SCHISTOSITY: is a term applied to the variety of rock cleavage found in rocks that are sufficiently recrystallized to be called schist or gneiss.

16. DEFINITION
LINEATION: Lineation is expressed by the parallelism of some directional property in the rock.