Melts, fluids, crystals: equilibrium and disequilibrium processes in magmatic systems

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Volatiles (H2O, CO2, S, F, Cl, Br, etc.) play a vital role in magmatic systems. Their concentrations affect phase equilibria, the timing and intensity of volcanic eruptions, and the formation of ore deposits. They played a major role in the evolution of the Earth following the Moon-forming giant impact, and their injection into the atmosphere during eruptions of large igneous provinces has been linked to major extinction events in Earth's history. The dominant volatile in magmatic systems is H2O, however the other volatiles are also commonly present at concentrations of 100's to 1000's of ppm. Although we know most about the effects of water in magmatic systems, some fundamental processes involving water remain unknown. We still do not understand completely the mechanisms and rates of water exsolution and bubble growth in magmas. The influence water exerts on the kinetics of crystallization and the equilibria between silicate melts and minerals, some of which are important reservoirs of trace elements and critical ore metals, is little understood. Even less is known about the effects of minor magmatic volatiles, which not only influence magmatic processes, but when degassed into the atmosphere severely impact Earth's surficial environment. Because of their low solubilities in melts, minor volatiles play a fundamental role in the exsolution of a fluid phase, possibly initiating volcanic eruptions. Additionally, at least two of these minor volatile elements, Cl and S, play a crucial role in the formation of ore deposits, particularly of critical metals (e.g., Li, Be, B, Co, rare earth elements, etc.). Importantly, we do not know enough about the behaviour of these minor volatiles in magmatic systems to quantitatively model their transport and storage. This research program will investigate equilibrium and disequilibrium processes involving major and minor volatiles and their interactions with crystals and melts in magmatic systems on Earth and other planetary bodies in the solar system. We will investigate their exsolution from the melt to form bubbles, develop new ways to estimate volatiles in ancient magmas and degassed into the atmosphere, and improve our understanding of the ability of volatiles to transport Cl, S and ore metals at conditions similar to those in crustal magmatic systems and following the Moon-forming impact. This research program is centered around experiments, modeling, and collaboration with colleagues working in the field applying the experimental results to natural samples. Because the research program will quantitatively measure storage and transport of critical metals, the results of the program will not only improve our understanding of the degassing of magmatic systems, but also will be used to model ore metal transport that can be applied to our search for critical mineral resources in Canada.