1. The Growth of Western North America - Part II The Insular Superterrane, North Cascades & San Juan Islands

2. Our Story So Far… C-3

3. Arrival of the Insular Superterrane Intermontaine Superterrane Insular Superterrane Methow Basin C-3

4. Intermontaine Superterrane Insular Superterrane Methow Basin North Cascades After Accretion Subduction zone relocates

5. North Cascades at 100 Myrs

6. Insular Superterane: Wrangellia Terrane Rocks: Basalts top: vesicles bottom: pillows Limestone Age: Triassic/Jurassic Source: Fossil clams and forams western Pacific Paleomagnetics ±15° N/S Type of Terrane: Hot Spot Islands Photo: Dr. ML.Bevier

7. Oblique Collision Continent Terrane

8. Oblique Collision Continent

9. Oblique Collision Continent

10. Oblique Collision Continent Terrane is “smeared out” along coast

11. Insular Superterrane: Wrangellia C-2

12. Wrangellia & the North Cascades C-6 Intermontaine Superterrane Insular Superterrane Methow Basin “Microterranes”

13. Modern Day Analogy for North Cascade Rocks

14. Cont. C-6 Intermontaine Superterrane Insular Superterrane North Cascades & San Juan Islands Time

15. Many Microterranes of the North Cascades & San Juan Is. (See list on C-9) C-4 Skagit Chelan Mountains Nason Shuksan Nooksak River Chilliwack Haro Turtleback Deadman Bay Garrison Decatur Western Melange Eastern Melange …and the rest…

16. Major Terrane Groupings Skagit Chelan Mountains Nason Shuksan Nooksak River Chilliwack Haro Turtleback Deadman Bay Garrison Decatur Western Melange Eastern Melange …and the rest… Skagit Crystalline Core NW Cascades and San Juan Thrust System Melanges

17. Major Terrane Groupings C-4 Skagit Crystalline Core NW Cascades and San Juan Thrust System Melanges

18. Skagit Crystalline Core Skagit Gneiss Cascade River Schist High Grade

19. NW Cascades Thrusts Darrington Phyllite Shuksan Blueschist Protolith: Shale Protolith: Basalt Chilliwack Marble -- Subducted Ocean Crust -- Low to Medium Grade

20. Twin Sisters Dunite

21. Major Terrane Groupings Skagit Crystalline Core NW Cascades and San Juan Thrust System Melanges High Grade Met. Medium Grade Met. Low Grade Met. C-4

22. Skagit Crystalline Core NW Cascades & San Juan Islands Thrusts Separated by thrust faults C-5 & 6

23. San Juan Islands C-7

24. San Juan Islands C-7 Decatur Terrane Jurassic Chert Basalt Gabbro Serpentinite Ocean Crust Similar to Terrane rocks in Northern California

25. San Juan Islands C-7 Deadman Bay Terrane Permian to Jurassic Chert Limestone W/Tethyan Forams Basalt Ocean Crust Similar to Cache Creek Terrane in Intermontaine Superterrane

26. San Juan Thrust Sheets C-7

27. San Juan Island Thrust Sheets C-8

28. NW Cascades/San Juan Islands C-5

29. Nanaimo Formation: Overlap Sequence

30. Mt. Stuart - Stitching Pluton 90 Myrs

31. Timing of the North Cascades Collision C-1 Age of the Microterranes Age of Accretion 115-90 Myrs

32. C-10 Meanwhile in Oregon…

33. Terranes of the Wallowa Mountains C-11