1. Sevier & Laramide Orogenies

2. The North American Cordillera

3. Cordilleran Structure

4. Orogenic Sequence

5. The Orogenic Belt

6. Propagation of Thrust Belts

7. “Decollement”

9. Foreland Basins

10. Foreland Orogen Basin

11. Sevier Orogeny 170 to 80 Million years ago

12. Sevier: horribly complex

13. Middle Jurassic: 170 – 160 Million years ago

14. Late Jurassic: 160 – 155 Million years ago Western Plate Margin Consolidates, accretion of Coast Range Ophiolite Farallon Plate Subduction Begins

15. Latest Jurassic: 155 – 142 Million years ago Voluminous Arc Magmatism Crustal Shortening

16. Early Cretaceous: 142 – 110 Million years ago Emplacement of “Mega-Thrust Sheet”

17. Middle Cretaceous: 110 – 85 Million years ago Onset of rapid shortening and Sevier Orogeny

18. Sevier: oversimplified

19. Sediments in the Foreland Basin The diagram shows two diferent kinds of sediments in the foreland basin: Sediment from the west is clastic sandstone and mudstone, eroded from the mountains of the thrust belt. Sediments from the east are shales and marine sediments which developed in a shallow sea. The dotted line shows the migration of sea level back and forth as sediments were deposited.

20. Laramide Orogeny 80 to 40 Million years ago

21. Sevier: another look

22. Laramide to the east

23. Laramide Involves Basement!

28. http://element.ess.ucla.edu/publications/1998_Laramide/RMF_velocity_movie.gif Follow this link for a neat movie!