UCL Earth Sciences


Evangelia K. Tripoliti

“Earth and Planetary Materials and High-Pressure and Temperature Experiments.”

PhD project title:

High Pressure and Temperature Crystallography of Mantle Silicates.

Evangelia K. Tripoliti
Project description:

I'm studying the thermoelastic & thermodynamic properties of mantle silicates, at realistic upper mantle (up to 660 km) temperature and pressure conditions by combining high-temperature X-ray diffraction with high-pressure experiments in the multi-anvil.

The main goal is to determine the crystallography of deep mantle silicate phases that have never been studied before and to create new equations of state.

To do this I’ll synthesize and characterise materials across garnet’s pyrope-majorite, Mg4Si4O12-Mg3Al2Si3O12, and olivine’s forsterite-fayalite, (Mg,Fe)2SiO4, solid solutions, and across majorite’s (Mg,Fe)SiO3 join. I'm particularly interested in the cubic to tetragonal phase transition that occurs within garnet's (Mg,Fe)SiO3-(Mg,Fe)3Al2Si3O12 join and the thermoelastic properties of the pure MgSiO3 endmember. I'm measuring the thermal expansion of my samples between 30 and 1500 K using powder and neutron X-ray diffraction. Additionally, single-crystal X-ray diffraction at the Natural History Museum and high-pressure experiments at international synchrotron radiation facilities are conducted to determine the full elastic constant matrix of my synthetic samples. Natural specimens provided by the Natural History Museum's collection are also examined. Finally, all output data will be compared to the literature and, where possible, to results from ab initio quantum mechanical calculations using the package VASP.

Academic Background:

BSc: Geoinformatics (2014)
MSc: Seismology (2017)

MSc: Geosciences (2018)