Experimental and theoretical studies of trace defects in minerals and other Earth materials

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Trace defects, including radiation-induced varieties representing incipient radiation damage, in minerals exert profound impacts on material properties such as color, density, rheology, stability, electrical and thermal conductivity, magnetism, seismic velocity, and many more. Trace defects in minerals and other materials also have a wide range of applications in Earth sciences from geochemical modeling to dosimetry, geochronology, remediation of heavy metalloid contamination, nuclear waste disposal, and mineral exploration. This research program is directed towards fundamental understanding of trace defects in minerals and other Earth materials, with emphasis on their electronic structures, magnetic properties, and novel applications. Scientific approach includes field-based investigations to identify trace defects of important geological applications and/or direct environmental relevance. Laboratory experiments are designed to complement field-based investigations and to provide synthetic materials for spectroscopic studies. Trace defects in selected minerals and their synthetic analogues are then characterized quantitatively by use of multiple analytical techniques, particularly electron paramagnetic resonance (EPR) spectroscopy and synchrotron X-ray absorption spectroscopy (XAS), and first-principles theoretical calculations. Specific research objectives for the next-funding cycle are: 1) experimental and theoretical studies of new radiation-induced defects in quartz, 2) uptake and speciation of heavy metalloids in common sulfates and phosphates, and 3) development of in-situ high-pressure-temperature EPR techniques for investigating iron spin dynamics in the Earth's mantle. This research program on the discovery and fundamental understanding of defects in minerals and related materials is unique in the Canadian Earth science community and is innovative in exploring the frontiers of both experiments and theory. Also, this research program provides an excellent opportunity for the training of highly qualified personnel in a multidisciplinary environment.