: “Plume”
3
4 Predictions
5 1. Precursory uplift Burov (2005)
6 2. LIP eruption Coffin & Eldholm (1993)
7 Campbell (2005) 3. “Tail” to core-mantle boundary
8 Hawaii 4. Time-progressive chain
9 5. High temperature
10 Plate
11 The Plate hypothesis
12 Predictions
13 Lithospheric extension Source fusibility Shallow mantle source
14 Many scientists beginning to doubt Plume and swing towards Plate Why?
15 Observations do not fit Plume predictions
Examples
No-one can agree on how many plumes there are, or where they are
18 Many “hot spot” lists
19 Flood basalt & chain: only 3/49! None fit all the predictions
20 Some spectacular disagreements
21 Hawaii
22
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
This is not scientific!
25 What about Plate?
26 The Plate hypothesis involves diverse processes
27 IT IS **NOT** ONE–SIZE–FITS–ALL
28 This immediately fits observations
What are these diverse processes? Examples
30 1. Continental breakup Van Wijk et al. (2001); Jones (2005)
31 Korenaga (2005) Ontong Java Plateau 2. Fertility at mid-ocean ridges
Ma Today 400 Ma Iceland
33 Beutel (2005) Examples Bouvet triple junction Azores triple junction Easter microplate 3. Extensional stress at plate boundary junctions
34
Iceland V- shaped ridges Hey et al. (2010)
36 Ferrari (2004) 4. Slab tearing & breakoff
37 Slab tearing at Samoa Samoa
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 Silver et al. (2006) Southern Africa Melt ponding & draining
40 Sublithospheric melt ponding & draining
That’s all folks