The geology, mineralogy, and geochemistry of gem and strategic element occurrences and the crystal chemistry of borosilicate minerals

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SUMMARY Repeated discoveries of both colored gems and strategic elements in Canada's extensive, but insufficiently explored and consequently untapped, land mass indicate the potential of becoming a significant producer of economically important mineral deposits. This research program will aid in exploration for such deposits by increasing our scientific understanding of the geological processes involved in forming them. The objectives of this research program form four project areas: gem deposits, pegmatites, carbonatite and alkaline intrusions, and borosilicates. Gem deposits are rare because the geological conditions needed to produce them are exceptional; for example, in order for emerald to form Be must come into contact with Cr or V, which occur in very different geochemical environments. However, with the exception of diamond, little has been done to develop exploration protocols for gem materials. My objective is to determine how these occurrences form, so that such protocols can be developed. In order to accomplish this objective, I will: (1) study the newly discovered Anuri emerald prospect in Nunavut, (2) apply exploration criteria developed for emeralds in Colombia to Canada, (3) characterize and develop deposit models for sapphire and (4) gem spinel on Baffin Island. Pegmatites have largely been overlooked in the Canadian Cordillera, even though Cordilleran pegmatites in the US have been significant producers of strategic elements, which are those elements that are at greatest risk of supply disruptions or are important to a country’s economy or defense, and gemstones for over a century. My long-term objective is to fill the information gap regarding the characteristics, classification, and formation of pegmatites of the Canadian Cordillera. In order to advance this objective, I will conduct geological mapping and study the geochemistry and geochronology of (1) the newly discovered Rau pegmatite field in the Yukon and (2) the Mt. Begbie pegmatites in BC. Information on the borosilicate minerals sheds light on the evolution of geological systems due to boron's role as both an incompatible element and a volatile in most melts. My objective is therefore to fully describe the crystal chemistry of selected borosilicate minerals so that it may be determined what geological circumstances must have given rise to those characteristics. In addition, dumortierite (the second most common borosilicate mineral) is used to make high-grade ceramics, and members of the supergroup are structurally related to a large group of synthetic microporous compounds that have potential commercial applications. I will continue advancing my work on this objective by (1) determining the positions and orientations of water molecules, (2) begin to study the crystal chemistry of the sakhaite-harkerite series of borosilicate minerals, and (3) investigate the stable and radiogenic isotopic compositions of the non-tourmaline borosilicates. Carbonatite deposits around the world have historically been sources of strategic element resources; therefore, I will continue my work on carbonatite and alkaline intrusions in western Canada. My objective is to fully characterize these strategic element occurrences in order to draw conclusions about the genesis of the mineralization, and to develop deposit models to aid in exploration. In order to advance this objective, I will study (1) the Kin carbonatite in BC and (2) the Bandito and Ting intrusions in the Yukon.