R3: High-pressure science and deep Earth's material

[R3-03] Compositional convection and solidification modes of the Fe-S core

*Satoru Urakawa¹, Hidenori Terasaki² (1. Okayama Univ., 2. Osaka Univ.)

Keywords:planetary core, Fe-S liquid, planetary magnetism, compositional convection

We evaluated adiabatic gradient of the Fe-S liquid core based on the thermal expansivity of Fe-S melts at high pressure. Comparing the adiabatic gradient with the liquidus gradient of the Fe-FeS binary system, we evaluated the solidification modes of the Fe-S core, of which liquidus surface is divided into two regions, bottom-up solidification region and the top-down solidification region. In both cases, core solidification could induce compositional convection to drive dynamo.