2. 2 1971 : “Plume”

3. 3

4. 4 Predictions

5. 5 1. Precursory uplift Burov (2005)

6. 6 2. LIP eruption Coffin & Eldholm (1993)

7. 7 Campbell (2005) 3. “Tail” to core-mantle boundary

8. 8 Hawaii 4. Time-progressive chain

9. 9 5. High temperature

10. 10 Plate

11. 11 The Plate hypothesis

12. 12 Predictions

13. 13 Lithospheric extension Source fusibility Shallow mantle source

14. 14 Many scientists beginning to doubt Plume and swing towards Plate Why?

15. 15 Observations do not fit Plume predictions

16. Examples

17. No-one can agree on how many plumes there are, or where they are

18. 18 Many “hot spot” lists

19. 19 Flood basalt & chain: only 3/49! None fit all the predictions

20. 20 Some spectacular disagreements

21. 21 Hawaii

22. 22

23. 23 Endless plume variants Lateral flow of plume material Tilted plumes Pulsing plumes Low 3 He/ 4 He plumes High 3 He/ 4 He plumes Headless plumes Tailess plumes Ridge-captured plumes Ridge-escaping plumes

24. This is not scientific!

25. 25 What about Plate?

26. 26 The Plate hypothesis involves diverse processes

27. 27 IT IS **NOT** ONE–SIZE–FITS–ALL

28. 28 This immediately fits observations

29. What are these diverse processes? Examples

30. 30 1. Continental breakup Van Wijk et al. (2001); Jones (2005)

31. 31 Korenaga (2005) Ontong Java Plateau 2. Fertility at mid-ocean ridges

32. 32 400 Ma Today 400 Ma Iceland

33. 33 Beutel (2005) Examples Bouvet triple junction Azores triple junction Easter microplate 3. Extensional stress at plate boundary junctions

34. 34

35. Iceland V- shaped ridges Hey et al. (2010)

36. 36 Ferrari (2004) 4. Slab tearing & breakoff

37. 37 Slab tearing at Samoa Samoa

38. 38 Cordery et al. (1997) eclogite Latent heat of fusion = 0  T = 200 K Lithosphere age = 6.25 Ma Max volume rate 0.8 x 10 6 km 3 /Ma 5. The issue of volume

39. 39 Silver et al. (2006) Southern Africa Melt ponding & draining

40. 40 Sublithospheric melt ponding & draining

42. That’s all folks