Plates vs. Plumes: A Geological Controversy Gillian R. Foulger Durham University, U.K.
2 Morgan (1971) The Plume Hypothesis
3
4 The Plate hypothesis
Top Down vs. Bottom Up
6 Predictions of the Plume Hypothesis
8 Burov (2005) 1. Precursory uplift
9 Coffin & Eldholm (1993) 2. Flood basalt eruption
10 Campbell (2005) 3. Plume “tail” to the core-mantle boundary
11 Hawaii 4. Time-progressive chain
12 5. High temperature
13 Predictions of the Plate Hypothesis
14 1. Lithospheric extension 2. Source fusibility 3. Shallow mantle source
15 Plume predictions are not confirmed
Precursory uplift
Emeishan basalts, China – 260 Ma
? Ukstins-Peate & Bryan, Nature Geoscience, 2009 Campbell, Elements, 2005
Time-progressive volcanic chains
21 Hawaii 80 Ma 50 Ma 0 Ma
22
Seismology – looking for plume tails
Seismic imaging is a can of worms Hmm… Is this a multi-headed plume?
Bruce map
Hawaii: Tomography Li et al. (2008) Wolfe et al. (2009) NW SE
Cao et al. (2011) 2000 km WE Hawaii: Receiver functions
No-one can agree on how many plumes there are, or where they are
Many “hot spot” lists
31 Tholeiitic provinces Ritsema & Allen (2003) Courtillot et al. (2003) Montelli et al. (2006)
32 Flood basalt & volcanic chain: only 3/49! None fit all the predictions
Endless plume variants Lateral flow of plume material Tabular plumes Pulsing plumes High 3 He/ 4 He plumes Low 3 He/ 4 He plumes Headless plumes Tailless plumes 33
34 Comparison with geosynclines Mio-geosyncline Eu-geosyncline Ortho-geosyncline Primary geosyncline Zeugo-geosyncline Para-geosyncline Exo-geosyncline Taphro-geosyncline Paralia-geosyncline
This is not scientific
36 What about the Plate hypothesis?
37 The Plate hypothesis involves diverse processes
38 This immediately fits the observations
Examples
40 Continental breakup Van Wijk et al. (2001); Jones (2005)
41 Silver et al. (2006) Southern Africa Melt ponding & draining is required
European Intraplate Volcanism Tamar Graben?
? ? ?
44 Beutel (2005) Extensional stress at plate boundary junctions
45
47 Slab tearing at Samoa Samoa
A comment on boxing matches…
That’s all folks