1. Modifying the Coast Transform Motion

2. Our Story So Far… Animated Cordillera Animated Cordillera - James Sears

3. Question still in debate… Where did the Insular Terrane actually accrete to North America? Intermontaine ST Insular ST N. Cascades Present Day WA State

4. Two Hypotheses Intermontaine ST Insular ST & N. Cascades Hypothesis A at 90 Myrs Hypothesis B at 90 Myrs WA State Baja BC Hypothesis

5. Baja BC 85 Myrs

6. Baja BC 80 Myrs

7. Baja BC 70 Myrs

8. Baja BC 60 Myrs

9. Main Evidence for Baja BC Paleomagnetics of Mt. Stuart Batholith Mt. Stuart 90 Myrs 30° inclination Eocene Volc. Rocks <55 Myrs 45° inclination (Modern lat.)

10. Other Evidence: Sediment Provenance Inconclusive - needs more study Source A Source B What do the overlapping sedimentary rocks tell us?

11. Other Evidence: Fossils What do the fossils tell us? New study - not yet published Supports Baja BC

12. Other Evidence: Plate Tectonic Reconstructions Supports Baja BC

13. However - there are problems… 1.No major faults discovered 2.Sedimentary rocks around the batholith are tilted…could it be tilted, too? The Question Remains Unanswered…

14. Post-Insular Plate Tectonics Graphics by Steve Dutch - U of Wisconsin D-2

15. 80Myr: Formation of the Kula Plate D-2

16. 55 Myrs D-2

17. 40 Myrs D-2

18. 30 Myrs D-2

19. 20 Myrs D-2

20. Present D-2

21. Major Events of the Cenozoic 65 55 45 35 25 15 0 5 Age (Myrs) Straight Creek Transform Fault Western Cascade Arc Challis Arc High Cascade Arc Columbia River Basalts Formation of Olympic Rocks Accretion of Olympic Rocks Major Sedimentary Basins VolcanismTectonicsOlympicsSedimentary Events Ice Ages