2

1971 : “Plume”

3

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are needed to see this picture.

4

Predictions

5

1. Precursory uplift

Burov (2005)

6

2. LIP eruption

Coffin & Eldholm (1993)

7Campbell (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 onhow many plumes there are, or

where they are

18

Many “hot spot” lists

19Flood 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 3He/4He plumes• High 3He/4He 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)

31Korenaga (2005)

Ontong

Java

Plateau

2. Fertility at mid-ocean ridges

32

400 Ma

Today

400 Ma

Iceland

33Beutel (2005)

ExamplesBouvet triple junction

Azores triple junction

Easter microplate

3. Extensional stress at plate boundary junctions

34

Iceland V-shaped ridges

Hey et al. (2010)

36Ferrari (2004)

4. Slab tearing & breakoff

37

Slab tearing at Samoa

Samoa

38Cordery et al. (1997)

• eclogite

• Latent heat of fusion = 0

T = 200 K

• Lithosphere age = 6.25 Ma

• Max volume rate 0.8 x 106 km3/Ma

5. The issue of volume

39

Silver et al. (2006)

Southern Africa

Melt ponding & draining

40

Sublithospheric melt ponding & draining

That’s

allfolks