[SIT31-06] Rising or falling snow: Constraints on core composition from the F-layer
Keywords:Earth's core, F-layer, Core composition
We employ constraints from mineral physics and seismology to determine core binary alloy compositions that are consistent with different solid particle fluxes within the F-layer. By allowing for the propagation of uncertainties of physical and chemical alloy properties at ICB pressures, we compute the thermal and compositional gradients across the layer. We find that a rising snow scenario is associated with the presence of a Si-rich core alloy, whereas the crystallization of hcp-Fe at the top of the F-layer favors an O-dominated core. These differences have strong implications for the resulting heat flow budget and for the driving forces for convection, which are of compositional nature for an Si-rich core, and are dominated by high heat fluxes and core secular cooling for an O-rich scenario.