1. Folds and Faults http://www.williamsclass.com/Sixt hScienceWork/FoldFault/FoldFaul tGeologyNotes.htm

2. Stress and Strain Stress is the applied force (The pushing and pulling on the rock layers). Strain is the bending & twisting that happens to the rock also known as deformation.

3. 3 Types of Stress 1. Compressional - pushes matter (rock layers) together. 2. Tensional - pulls matter (rock and dirt layers) apart. 3. Shear is rotational, the stress is parallel to a face of the material,

4. Types of Strain: Elastic or plastic? All applied stresses cause rock (or any other solid) to deform (strain). Strain can be elastic or plastic. Elastic strain disappears on the release of the stress. (like a rubber band) Plastic strain is permanent on release of stress. (like clay)

5. Ductile or Brittle If a material undergoes continuous plastic deformation, it is said to be ductile. If it fractures, it is said to be brittle.

6. The 3 parts of a fold: fold axis axial plane limb

7. The 4 Fold shapes 1. symmetrical 2. asymmetrical 3. overturned - tipped in one direction so that one of the limbs is overturned 4. recumbent - lying on its side

8. There are three types of folds: 1. Anticline 2. Syncline 3. Monocline

9. 1. Anticline

10. 1. Anticline (continued) This is when layers are folded upwards in what looks like an arch. The layers are symmetrical (look alike) to either side of its center. Rock layers in anticlines dip away from the center axis. The oldest rocks are exposed on the center axis.

11. 2. Synclines

12. 2. Syncline (continued) This is when the rock layers are folded downward. The youngest layers of rock are exposed on the center axis.

14. Which is which?

15. Monocline This is when the rock layer has a gently dipping bend in the horizontal rock layer.

16. 3. Overturned Overturned folds in the Baltimore Gneiss Baltimore County, Maryland

17. Faults When rocks are deformed (broken) brittly, they are displaced along fractures called FAULTS.

18. Breaks in rock are put into two categories Fractures/joint: When there is no movement along either side of the rock break. Fault: When either side of the rock break moves in opposite directions.

20. FAULT TERMINILOGY 1) "Hanging Wall"- The surface of block that is on top of the plane of the fault. 2) "Footwall"- The surface or block that lies below the plane of the fault.

21. 3) "Strike"- The direction in which the fault runs. 4) "Dip"- The dip direction is perpendicular to the strike direction.

22. Types of faults 1. Dip-Slip Faults: Movement along dip-slip faults is vertical; one side moves up and the other side moves down. The two types of Dip-Slip Faults are A)Normal Faults B)Reverse Faults

23. Normal Fault: The hanging wall has slipped down in comparison to the foot wall. Gravity causes the hanging wall to slip down. Normal Faults are from layers being pulled apart. Also known as a GRAVITY FAULT. A. Normal Fault

25. Reverse Fault: The hanging wall has slipped up in comparison to the foot wall. When layers are pushed together this is the kind of fault that occurs. Also known as a THRUST FAULT. B Reverse Fault

27. Strike Slip Fault 2. Strike Slip Fault: Two layers of rock are shifted horizontally or parallel to the fault plane. Example – The San Andreas Fault

28. San Andreas Fault in California

30. What are the three types of stresses? What is the elastic limit? What is a geological cross section? What is metamorphic rock? What is the hinge line? What are: Plunging folds, open folds, isoclinal folds, overturned folds, recumbent folds? Look at the pictures or diagrams – they help to clarify!!!