The power balance at the core–mantle boundary

The power ( P ) required by the mantle from the core, previously thought to be about 2.3 TW, is shown to be about 8 TW. Mantle heat transfer mechanisms near the core–mantle boundary (CMB) called sinks control power input into the mantle. The sinks are mechanisms for: heating the slab at the base of the mantle sufficiently to equilibrate its temperature; sustaining plumes whose surface signatures are hotspots and continental flood basalts (CFBs); conducting heat along the mantle’s adiabat evaluated at the CMB; sustaining plumes whose surface signatures are seamounts; and sustaining hot, weak plumes that never reach the lithosphere (with no surface signature) but are found in numerical simulations of mantle convection. The total power of the sinks is supplied by core heat sources. The major source is conductive power. The conductive power equation for the core is re-evaluated with new mineral physics data on the Grüneisen parameter and thermal conductivity. The new value is P(conduction)=6.8 TW. Convection and radiogenic sources supply the additional power required.