Synthesis

Gillian R. Foulger

Post-meeting books?

1. Book of review articles– Chemical Geology (Elsevier)

2. AGU monograph– Book of regular papers

Everyone is invited to contribute to

www.mantleplumes.org

Key points 1

1. Alternatives do not amount to a single, generic, one-size fits all replacement model for plume

– generic elements, but each locality individual, e.g., OJP, Hawaii, Azores

Key points 2

• Consistent terminology imperative– Use of properly defined/explained terms. – It isn’t enough to just say “plume”– Problem of falsification

Key points 3

• ~ 1,000-km-wide magmatism - predicted by both?

• Time-progressive track - predicted by both?• Uplift. Domal? - complex pattern predicted by

both? • Temperature - necessary?• CMB origin - detectable?

Key points 4

• Opinion of relationship between plate tectonics & plumes.

Key points 5

• Problems with publications:– Standard of interpretations (cart before horse)– Repetition of old, wrong data e.g. ages,

temperatures.

Important problems 1

• Mantle physics

– Self-consistent models that can produce plate tectonics required.

– Better understanding of critical mantle physical parameters, e.g. CMB heat flow, LM viscosity

– How important is small-scale convection?

• Lithosphere physics

– Behaviour of lithosphere when major thermal event occurs - plume, delamination, rifting, meteorite?

– Response of lithosphere to stress - cracking?

– Characterise lithospheric stress

– What causes rifting?

Important problems 2

• Temperature– Petrological

temperatures

– Phase equilibrium of CO2-bearing systems

– Melting at all depths

– other geothermometry methods e.g. seismological

• Geochronology– More high-quality

dates

– Re-date important chains where old dates inadequate.

– LIP ages. Can we be more specific?

Important problems 3

• Seismology– Interpreting mantle seismic

anomalies in the mantle and D” - hot? cool? buoyant? dense?

– Very wide seismic tomography?

– Transfer of material between UM & LM?

– Are innovative high-resolution experiments feasible?

• Planetary– Sort out Venus.

– Look for meteorite evidence in geology.

Important problems 4

• Field evidence– Make diagnostic

observations, e.g., uplift?? temperature, mantle structure.

– Potential plume localities?

– Can we distinguish cause and effect, e.g. rifting & volcanism?

– Address problems of the Emperor-Hawaii system.

• Petrology & Geochemistry– Improved melt generation

models needed

– Melting: high-P trace-element partition coefficients needed

– Where/what is/are the OIB sources?