Magmatic geochemistry of chalcophile and siderophile elements

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The chalcophile and siderophile elements have long been recognised as valuable tracers of the processes responsible for small- and large-scale differentiation of the terrestrial planets, in addition to their societal uses as elements with unique thermal, surface and electronic properties.  Despite their importance in this regard, much of our current knowledge of the geochemistry of these elements is empirical, and subject to considerable uncertainty. However, a detailed understanding of their geochemical behaviour is essential to fully interpret natural abundance data, and develop advanced models for ore exploration.  Over the past five years, my research has focused on developing techniques and implementing experiments to better assess the role of magmatic processes in controlling the behaviour of a subset of these elements, namely Re and the platinum group elements.  In the next funding cycle, I plan to expand the scope of this work to include the poorly understood chalcophile non-metals and metalloids Pb, Se, Te, As and Sb.  These are elements that are typically present at trace to minor abundance levels in base metal sulfide segregations, and in some cases may be the principal anion in minerals that concentrate the siderophile elements.  The proposed work will specifically focus on the extent to which these elements are transferred and concentrated within Earth's crust and mantle.  Experiments will be done using facilities at University of Toronto, employing machines that simulate the extreme conditions of the deep Earth, and a novel centrifuge device for separating mixed samples at high temperature.  The products of these experiments will be characterised using state-of-the-art analytical techniques, including laser ablation ICP-MS, and synchrotron-based spectroscopy.