1. Review from LAB #3

2. Grain-scale shear sense

3. Homework examples delta-type

4. Homework examples S-C Mylonite
when you know the schistose foliation and shear bands formed at the same time than S-C mylonite. Develop best in a micaceous granite protolith S

5. Homework examples sigma-type

6. The Traction Vector and Stress Tensor
LAB #4
The Traction Vector and Stress Tensor

7. From Force to Stress
Traction
Force
Stress at a Point
Surface Stress

8. The Stress Tensor
“on in”

9. Sign Convention Positive Shear Stress Negative Shear Stress
Determined by direction of traction acting on negative coordinate face
Negative Shear Stress
Tractions are positive in negative coordinate direction

10. Principle Stresses

11. Stresses in Principal Stress Frame
angle is between normal to plane and maximum principal stress orientation

12. The Mohr Circle
a way to visualize the relationship between shear and normal stresses