Thermal Evolution

Core: Pressure and temperature with depth

• Pressure and temperature increase with depth
• Adiabat - the change in temperature with depth (pressure)
• Liquidus - temperature below which liquid begins to freeze
• Inner-core location depends on liquidus and adiabatic curves
• where adiabat is lower than liquidus, solid iron forming (freezing)
• If solid core forming then additional heating from latent heat and gravitational energy
• Existence and size of inner core unknown but a freezing core provides additional energy to power a dynamo

• Heat conducted across the core-mantle boundary (CMB) and the lithosphere (rigid upper boundary of the mantle)


• Liquid iron-rich core convects


• Mantle interior convects (solid state convection) with a temperature-dependent viscosity


• Core cooling determined by mantle's ability to remove heat (vigor of convection)