The behaviour of metals in magmatic-hydrothermal systems

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Understanding the behaviour of metals in magmatic-hydrothermal systems is the key to deciphering the origin of many types of ore deposits. This understanding has improved dramatically in the last few years because of the development of laser ablation induced couple plasma mass spectrometry (LA-ICP-MS) analyses of metals in minerals, fluid inclusions and melts inclusions. The proposed research will take advantage of this technique to study 'rare-metal' (Ta-Nb-Sn-W-Mo) and precious metal (Pt-Pd-Au) ore deposits. The rare-metals are increasingly more important as new uses in electronics and specialty alloys are developed, and because of high prices, the interest in precious metals continues to be strong. It is necessary to better understand of the processes that concentrate these elements in order to improve exploration models. This will be accomplished by field investigations, where the abundances of the ore metals will be determined in fluid and melt inclusions. From these data the relative importance of magmatic versus hydrothermal processes will be evaluated. The field studies will also examine whether characteristic elements are concentrated in key minerals. The spatial and temporal relationships between these indicator minerals and mineralization will be characterized and applied to generating genetic models of ore deposits, and evaluating the use of indicator minerals to exploration of hydrothermal ore deposits. Complementary experimental studies will also be conducted. These include determining the diffusivity of Ta and solubility of tantalum minerals in granitic melts, and the use of synthetic fluid inclusions to study element partitioning, notably Au-As-Sb-Mo-W, between vapour and liquid phases of immiscible fluids.