Light elements in the core of a habitable Earth

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Important information about the formation of our planet and how it became habitable may be hidden under our feet in the deep Earth, namely in the core. The nature and abundance of light elements (particularly C, Si, O or S) are closely related to planet formation and the geodynamo that protects life on the Earth s surface from the destructive effects of the solar wind, and are crucial parameters in understanding the evolution of the Earth s atmosphere. Systematic experimental data on alloys and compounds of iron with potential light element(s) at Earth s core conditions (multi-megabar pressures and temperatures over 3000 K) are either limited, inconsistent, or absent. The goal of the project is to study the phase relations and thermoelastic properties of phases in the binary Fe-L (L=Si, O, S, C) systems using novel in situ single crystal X-ray diffraction in laser heated diamond anvil cells. We will obtain information crucial for understanding the chemical differentiation of the Earth to contain a metal core, modelling the past and present history of the core, and the effect of core formation on the development of a habitable planet. Special attention will be focused on investigations of the following compounds: FeO, Fe3C, Fe7C3, Fe3S, Fe2S, FeS, Fe3Si, and FeSi. In addition to X-ray diffraction methods, samples will be studied by multiple complementary techniques (Moessbauer, Raman and infrared spectroscopies, TEM, SEM, microprobe analysis, etc.).