Source-migration-trap models for precious metal deposits

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The processes related to the formation of anomalous concentrations of elements in the earth crust, also known as ore deposits, can be unraveled by evaluating source-migration-trap models at various scales of observation (from global to deposit-scale). My research over the next years will concentrate mainly on understanding the processes that are critical in the formation of world-class gold deposits (>3 million ounces of gold) hosted in sedimentary sequences. Two areas have been selected to focus the investigations over the next five years: Northern Nevada which hosts the Goldstrike Deposit (> 50 million ounces gold) and the Brazilia Belt, which hosts the Morro do Ouro Deposit (> 18 million ounces gold). This research program involves both regional and local-scale multidisciplinary studies, and the application of state-of-the art techniques to bring new insights into understanding the formation of large accumulations of gold in the upper crust. This will lead to the development of integrated source-migration-trap models and will help to refine exploration strategies of mining companies, increasing the potential for successful exploration programs in Canada, in areas sharing similar characteristics. Furthermore, the new integrated approach to investigate the mode of occurrence of gold and trace elements in sulfides also has important applications to the field of material and environmental sciences. Although arsenian pyrite, an arsenic-bearing iron sulphide, is widely known for its role as an important host for gold in ore deposits, it is also a major source of arsenic in sedimentary rocks, mine wastes and tailings. Understanding its crystal structure and crystal chemistry will be very important to evaluate its behavior during processing and weathering, and to mitigate problems related to environmental contamination by arsenic and related elements. This research program will involve training of highly qualified geoscientists who will be working in multidisciplinary collaboration between industry, government agencies, and colleagues from other research centers.