9. ULVZ at the base of the Earth’smantle Rost et al., 2005
10. Deepmantlemelting Vp and Vs reduction up to 10 and 30% respectively (Rost et al., 2005) Density of the melt up to 50% higher than solids Thickness of 40km maximum
11. A dense melt? Chemicaleffect: Fe enrichment Structural effect: densitycross-over of the meltaround 80GPa (Mosenfelder et al., 2007)
12. Magenticfieldgenerated by a dynamo core cooling(5TW) 1000K of coolingthrough 4.5Ga Deepmelts are as old as the planet When has this melt formed?
45. Fromearly to modern Earth Remnants of magma ocean stage at the base of the mantle Intese and widespsreadvolcanism in the Hadean (no plate tectonics) Flooded and flat ArcheanEarth Slowlycooling modern Earthwithstrongcrust and uppermantle