Summary of key observational / experimental constraints on models of subduction zones

Result of breakout discussion group moderated by Tim Grove

Key observations to Match

1. Heat flow
2. Gravity and Geoid
3. Topography
4. Slab dip (geometry)

Key observations to match/assess

1. Distribution of volcanoes above slab in 2D and along-strike in 3D
2. Pressure and temperature conditions at the top of the mantle wedge
3. Low seismic velocities at the top of the slab
4. Thickness variations observed in the upper plate
5. General seismic attenuation and velocity structure of the wedge
6. Presence/absence & time duration of back arc basins + Asymmetry of Pacific subduction zones
7. Limits of shallow seismogenic zone
8. Seismic anisotropy of the wedge
9. Major element compositions of primitive lavas

Observations not to be used as constraints

1. Temperature at the slab/wedge interface. What is the conceivable range?
2. Time scale inferred for melt transport.

Issues to explore

1. Influence of 2 phase flow
2. Does the incorporation of water in the slab have important consequences?