1. 26 October 2004GLG310 Structural Geology

2. 26 October 2004GLG310 Structural Geology Shear Zones Have a look at Davis and Reynolds, Chapter 9

3. 26 October 2004GLG310 Structural Geology Shear Zones

4. 26 October 2004GLG310 Structural Geology Shear Zones

5. 26 October 2004GLG310 Structural Geology Shear zones Brittle or ductile –Brittle shear zone = fault zone Tabular or sheet like, planar or curviplanar zone composed of rocks that are more highly strained than the rocks adjacent to the fault zone Quartz starts to flow rather than fracture at about 300C

6. 26 October 2004GLG310 Structural Geology Semi-brittle shear zones

7. 26 October 2004GLG310 Structural Geology 2004 Parkfield Earthquake Ramón Arrowsmith & special guest Matt Fouch Earthquake of the Month: Special Seminar

8. 26 October 2004GLG310 Structural Geology

9. 26 October 2004GLG310 Structural Geology

10. 26 October 2004GLG310 Structural Geology

11. 26 October 2004GLG310 Structural Geology

12. 26 October 2004GLG310 Structural Geology

13. 26 October 2004GLG310 Structural Geology

14. 26 October 2004GLG310 Structural Geology

15. 26 October 2004GLG310 Structural Geology Brittle-ductile s.z.

16. 26 October 2004GLG310 Structural Geology Sense of shear S-C fabric: S surface = schistosity, C surface = shear surfaces

17. 26 October 2004GLG310 Structural Geology Sense of shear

18. 26 October 2004GLG310 Structural Geology Sense of shear: Ductile shear zone

19. 26 October 2004GLG310 Structural Geology Pure vs. Simple shear

20. 26 October 2004GLG310 Structural Geology Pure vs. Simple shear

21. 26 October 2004GLG310 Structural Geology Analysis of shear strain Continuous or discontinuous strain

22. 26 October 2004GLG310 Structural Geology Transpression or Transtension Can have both pure and simple shear along a shear zone

23. 26 October 2004GLG310 Structural Geology -R+A Velocities relative to stable North America

24. 26 October 2004GLG310 Structural Geology