1. structural geology & mountain building

2. key terms
Deformation – change in the original form, size or shape of a rock unit
Stress – amount of force applied to a given area
Differential stress – stress applied unequally in different directions
Strain – causes irreversible changes in the shape, size or orientation of a rock unit
Elastic deformation – recoverable stress, when stress is removed rock returns to its original shape & size
Ductile deformation – elastic limit of rock is exceeded, the rock flows into a new shape, size or orientation
Brittle deformation – elastic limit and ductile limit of rock is surpassed, failure occurs, the rock breaks
Joint – a crack along which there is no motion

3. Stress, strain & deformation
When does failure occur?
How is deformation in a stick like deformation of a rock unit?

4. effects of directional stress
Compress ional stress – causes rock units to shorten horizontally & thicken vertically
Tensional stress – causes rock units to lengthen horizontally & thin vertically
Shear stress – causes horizontal displacement along fault zones

5. strike & dip
Strike – compass direction of a line where a rock layer intersects the horizontal
Dip – angle of inclination or tilt of a rock layer from the horizontal

6. Terminology of folds Limb – sides of a fold
Axial plane – imaginary plane that divides a fold as symmetrically as possible
Axis – intersection of axial plane with the surface
Symmetrical – limbs are mirror images of each other
Asymmetrical – limbs are not mirror images of each other
Overturned – a fold in which one limb is tilted beyond the vertical
Recumbent – a fold folded over on itself
Plunge – a fold in which the axis is tilted from the horizontal

7. types of folds
Syncline – downwarping of strata, older strata are found on limbs, younger strata in the axial region

8. types of folds
Anticline – upwarping of strata, older strata are found in axial region, younger strata on the limbs

9. types of folds
Asymmetrical – either an anticline or syncline in which one limb is tilted at a different angle than the other

10. types of folds
Recumbent – a fold which is folded over on itself

11. fault terminology
                                                    
Fault – fracture in rock along which there has been displacement
Hanging wall – rock surface above the fault
Footwall – rock surface below the fault
Fault scarp – exposed fault surface

12. types of faults
Normal fault – a fault in which the hanging wall moves down relative to the footwall

13. types of faults
Reverse fault – a fault in which the hanging wall moves up relative to the footwall

14. types of faults
Strike-slip fault – a fault in which the motion is in the horizontal plane, also a transform fault

15. types of faults
Thrust fault – hanging wall moves up and thrusts over the footwall, the dip is less than 45 degrees, low angle fault

16. domes & basins
Basin – circular or elongated structure caused by downwarping of sedimentary rock
Youngest rock found in the center of the basin, older on the flanks
Dome – circular or elongated structure caused by upwarping of sedimentary rock, usually overlying igneous or metamorphic rock
Youngest rock found on the flanks of the dome, oldest in the center

17. Hogbacks Ridges of steeply dipping strata
Highly resistant sedimentary layers remain exposed along the edge of an uplifted block

18. orogenesis Orogenesis – processes by which mountain belts are created
Oros – mountain, genesis – to come into being

19. Types of mountains
Fault block mountains – mountain belts formed by extensional forces
Mountains are associated with high angle normal faulting
Examples include: Sierra Nevada, Grand Tetons, “Basin & Range province

20. Types of mountains
Folded mountains – result from large scale compressional forces
Rock units are shortened and thickened as a series of synclines and anticlines forms a mountain belt
Examples include: the Appalachians Valley and Ridge Province

21. Terrane accretion
Small crustal fragments collide and merge with larger continental masses
Accreted crustal blocks are called terranes
Accretion of larger fragments may result in formation of a mountain range
Examples include: the western coast of North America