Presentation is loading. Please wait.

Presentation is loading. Please wait.

Announcements Cottonwood exercise and homework are due on Thursday The project for those who missed the field trip is now available online- deadline for.

Similar presentations


Presentation on theme: "Announcements Cottonwood exercise and homework are due on Thursday The project for those who missed the field trip is now available online- deadline for."— Presentation transcript:

1

2 Announcements Cottonwood exercise and homework are due on Thursday The project for those who missed the field trip is now available online- deadline for that is Tuesday March 25, in class (no extensions!, zero credit after deadline)

3

4 Cottonwood trip- a few thoughts

5 Changes in dips? How can you explain them?

6 Definitely a fault; what kind?

7

8 Need to think about cross- section

9 Strike-slip fault systems (D&R: ) 1. Tectonic settings and significance 2. Geometries 3. Active strike-slip faults- 4. mineralization + petroleum

10 At the scale of plate tectonics, transform (strike-slip) plate boundaries are subordinate to convergent and divergent plate margins- but they play a critical role

11 oceanic (ridge-ridge) transform faults, revisited

12 Continental strike-slip faults- the San Andreas

13

14

15 How deep should earthquakes be within an active strike-slip fault? Down to the brittle-ductile transition

16 The Alpine fault in New Zealand transfers slip between two subduction zones (trench-trench transform)

17 The North Anatolian fault-rupture near Izmit last September.

18 Major active continental strike-slip faults in Asia

19 tectonic extrusion or escape hypothesis

20 Strike-slip faults can transfer slip between different thrust or extensional systems

21 Strain can be partitioned into different styles of fault systems-

22 Strain partitioning in oblique convergent margin settings

23 Fault traces are rarely straight- they can curve, branch, or be arranged en echelon. This leads to a wide variety of strike-slip related deformation

24 Transtension in releasing bends may lead to development of sag ponds and pull-apart basins

25 Restraining bends and transpressional deformation- folds and thrusts

26 The San Andreas bend near Los Angeles: thrusting related to strike-slip faulting

27 Many strike-slip fault systems are characterized by faults that converge downward and form flower structures compressional setting: "positive" or "palm tree" flower structure extensional setting: "negative" or "tulip" flower structure

28 Some flower structures look like duplexes turned on their side- strike-slip duplexes

29

30 Riedel shears- especially common in strike-slip fault systems R: synthetic Riedel shear R': antithetic Riedel shear P: synthetic shear, subordinate to R and R' or absent

31 summary of strike-slip-related deformation

32 What is important about strike-slip faults and why do we care? 1. Many active strike-slip faults are associated with high slip rates, major earthquakes, and lithospheric plate boundaries 2. Oil and mineral exploration.

33

34

35 Significance of strike-slip fault systems for oil

36 Many Archean and Phanerozoic mineral deposits (especially gold) are associated with zones of strike-slip deformation

37

38

39

40 Important terminology/concepts ridge-ridge and trench-trench transform faults concept of continental extrusion or escape strike-slip faults as transfer faults strain partitioning oblique convergence releasing vs. restraining bend transpression vs. transtension sag ponds and pull-apart basins flower structures strike-slip duplexes right-stepping vs. left-stepping fault arrays folds in strike-slip zones Riedel shears


Download ppt "Announcements Cottonwood exercise and homework are due on Thursday The project for those who missed the field trip is now available online- deadline for."

Similar presentations


Ads by Google