Crystallography at Extreme Conditions

Understanding the mineralogical composition and chemical zoning of the Earth's upper mantle and Transition Zone requires knowledge of all its constituent material phases. Despite the large volume of information about the Earth's interior, there are still major phases within the MgO, SiO2, FeO, Al2O3 and Na2O systems whose properties have not been accurately determined, and in some cases not defined. The complicated structure of several of these phases, and the difficulty attaining information at high pressures and temperature have significantly attributed to the rise of inconsistencies and gaps in the literature. The purpose of this PhD research thesis is to synthesise and measure these materials by performing and combining several high-pressure and high-temperature X-ray and neutron diffraction experiments conducted at university, national and international laboratory facilities. Crystallographic data collected in this thesis will be used to create various Equations of State to assess the Earth's mantle dynamics and elasticity, that can further be used for modelling of other planetary interiors, and to provide robust constrains on the mineral and chemical composition of the upper Earth's mantle, up to 660 km.