Mineral Phase Diagram

Pressure-temperature phase diagram for silicate minerals — mantle discontinuities

Olivine (α)
Wadsleyite (β)
Ringwoodite (γ)
Bridgmanite + Fp
Post-Perovskite
Melt
Hover or click the diagram to explore phases
Geotherm Slope (K/km)7.0
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The 410 km discontinuity is caused by the olivine → wadsleyite phase transition at ~13 GPa, 1400–1600°C. The 520 km discontinuity reflects wadsleyite → ringwoodite. At ~23 GPa (660 km), ringwoodite breaks down to bridgmanite + ferropericlase — the most abundant mineral in Earth (lower mantle). The D″ layer at 2700 km shows post-perovskite (bridgmanite → ppv). Cold subducting slabs deflect transition depths; hot plumes deflect them the other way — seismically observable.