The Experimental Mineral Physics group at the Department of Earth Sciences applies a high-pressure and high-temperature experimental approach mainly using a laser-heated diamond anvil cell technique to reproduce the deep Earth's condition in the laboratory. With this method, the group is trying to clarify the issues including the determination of density, crystal structure, elasticity and chemistry of the deep Earth's materials to understand the mineralogical model and evolution of the Earth's deep interior.
The group led by Prof. Motohiko Murakami is seeking two motivated doctoral students to study elasticity of deep Earth’s materials. Those two positions are funded for four years by the Swiss National Science Foundation (SNF).
The Earth's core-mantle boundary (CMB) where the solid silicate mantle is in direct contact with the molten iron core is known as the largest thermal and chemical boundary region in the Earth, which has served as the primary driving force of the mantle convection throughout the entire history of the solid Earth. Therefore, the physical and thermochemical nature of CMB has been considered as one of the most important keys to explore the dynamics and thermochemical evolution of the Earth's mantle.
It is well known that some anomalous and unusual seismic signatures have been observed characteristically around D" region which is a ~200 km thick layer of the lower mantle just above CMB, such as D" seismic discontinuity, shear-wave splitting, ultralow velocity zones (ULVZs), and negative shear velocity jump. Although extensive studies ranging from theoretical to experimental fields have so far been made to clarify those anomalous seismic features within the D" layer, it still remains highly speculative as to what kind of primary factors have caused those seismic anomalies mainly due to the critical lack of the conclusive experimental evidences as discussed in detail later in this section. The lack of knowledge on the origin of those seismic observations at CMB has severely prohibited us to discuss the thermochemical nature at CMB quantitatively.
The aim of this research project is to experimentally determine the essential physical properties such as elasticity, structure and density of the candidate minerals in-situ under CMB condition, and to give stronger constraints on the possible causes of the anomalous seismic observations in D" layer from experimental mineral physics point of view.
The research activities for both positions involve the experimental exploration of elasticity of deep Earth's materials using in-situ high pressure/temperature Brillouin scattering spectroscopy in a laser-heated diamond anvil cell.
Applicants for these two PhD positions are expected to have an excellent MSc degree in Earth Sciences or other relevant field such as material science or high-pressure physics. Experience in the field of high-pressure experiments using a diamond anvil cell apparatus and/or laser spectroscopy (Raman, Brillouin) are beneficial and highly valued. We are looking for highly motivated, committed, and creative individuals, able to work in a team and with excellent communication skills. The positions are available from November 2020 onwards.