Orogeny

1. RECAP

2. What is the theory that explains and unifies different geologic phenomena? Recap

3. What is the theory that states that continents were once joined and then they broke apart? Recap

4. Give 3 evidences of Continental Drift provided by Wegener. Recap

5. What do you call the remanent magnetism from ancient rocks recording the direction and strength of the Earth’s magnetic field at that time? Recap

6. What is the theory that states that the seafloor separates at oceanic ridges? Recap

7. Mountain Formation Results of Tectonic Plate Convergence

8. Colliding plates provide the compressional forces that fold, fault, and metamorphose the thick layers of sediments deposited at the edges of landmasses Orogeny at Convergent Boundaries

9. Ocean-ocean convergence mainly produces volcanic mountains These features tend to be long-lived Examples: Aleutian Islands (Alaska) and Japan Ocean-Ocean Convergence

10. The Japanese Islands

11. The convergence of the continental block and the subduction of the oceanic plate leads to deformation and metamorphism of the continental margin Partial melting of mantle rock above the subducting plate generates magma that migrates upward Ocean-Continental Convergence

12. The types of mountains formed by ocean-continental convergence are volcanic mountains and folded mountains Examples: Andes (South America) and Cascades Ocean-Continental Convergence

13. Ocean-Continental Convergence

14. Ocean-Continental Convergence

15. Ocean-Continental Convergence

16. Andes Mountains

17. Continental crust floats too much to be subducted At a convergent boundary between two plates carrying continental crust, a collision between the continental fragments will result and form folded mountains Examples: Himalayas (Asia), Urals (Russia), and Appalachians Continent-Continent Convergence

18. Continent-Continent Convergence

19. Continent-Continent Convergence

20. Classic folded terrain: well-developed anticline

21. ZAGROS MTS PERSIAN GULF Alternating Anticlines and Synclines

22. Most mountains are formed at convergent boundaries, but some are formed at divergent boundaries The mountains that form along ocean ridges at divergent plate boundaries are fault-block (folded) type mountains Example: the 65,000 kilometer long mid-ocean ridge system Orogeny at Divergent Boundaries

23. Mid-Atlantic Ridge

24. Where is the longest mountain range? Concept Check