Structural Changes in Minerals and their Effect on Intrinsic Properties

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My research program examines mineral behaviour (physical, mechanical, thermodynamic, elastic, and chemical properties) as a function of pressure (P), temperature (T), composition (X), and time (t), that is, P-T-X-t conditions. Mineral behaviour provides realistic models for Earth processes because mineral properties are governed by their crystal structure. In my group, we try to answer questions such as why do solid materials have the composition, structure, and the properties that they exhibit? How do these properties change under different P and T conditions? How does the ordering of atoms in a structure change in response to P-T-X-t conditions? We use various in situ experimental techniques to investigate the processes that govern mineral stabilities and properties under ambient and non-ambient (different P and T) conditions and apply the results to Mineral Physics and Earth processes. We use experimental techniques in university laboratories and at synchrotron and neutron facilities. My group members investigate minerals that receive significant interest to the scientific community because of their technological properties and their usefulness in understanding earth processes. For example, garnet-group minerals are important because they occur over a range of P-T-X-t conditions and they preserve important records of igneous and metamorphic processes. Garnet-group minerals have important uses in lasers and automotive batteries. Some garnets are zoned, which affect their properties. Compositional zoning is well known in feldspars and about 75 other minerals, so our work will have implications for numerous minerals. Zoning in minerals must be considered in their thermodynamic behaviour and their effective use in geothermometry, geobarometry, and geochronology. Moreover, order-disorder processes affect seismic velocities and are needed for geophysical models. My HQP will learn important techniques to solve problems in the fields of mineralogy, crystallography, and materials science. Our findings have the potential to lead to significant discoveries that will benefit the Canadian economy.