[S-IT18] Planetary cores: Structure, formation, and evolution

[SIT18-02] Core evolution in the presence of a basal magma ocean

★Invited Papers

*Amy Ferrick¹, Jun Korenaga¹ (1.Yale University Department of Earth and Planetary Sciences)

Keywords:basal magma ocean, inner core, thermal evolution

The thermal evolution of planetary cores is regulated by convection of the overlying solid mantle. If we are to gain insight into the history of Earth’s core cooling, which is still quite uncertain, careful consideration of the mantle and its possible histories is therefore crucial. It has been suggested that a long-lived basal magma ocean (BMO) at the base of the mantle may insulate the core from the heat flux demanded by mantle convection, thereby lowering core cooling estimates by up to several terawatts (Labrosse et al., 2007. Nature 450. doi:10.1038/nature06355). While the concept of a slowly crystallizing BMO has recently gained popularity, quantitative studies on its consequences for Earth’s evolution—including that of the core—are few. We recently conducted thermal evolution modeling of Earth assuming the presence of a BMO, and demonstrate how the core’s thermal history depends on a BMO along with other mantle assumptions. We show that, while the BMO indeed insulates the core to some extent, a long-lived inner core is still likely.