Magmatic hydrothermal alteration systems

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This specific research application focuses on complex infiltrative metasomatic reaction systems, which indirectly relates to the spectrum from magmatic volatile evolution through to the distal precipitation of metals; this proposal is an extension of his research on skarn systems that has had several key impacts, which most notably are: 1) some important phase relations have been highlighted in mixed volatile, infiltrative contact metasomatic systems, 2) permeability evolution during solution-hostrock reaction coupled with and analysis of physiochemical reactions, and 3) the provocative petrogenetic interpretation of some derivative igneous rocks, their gases, and eruptive style has a wide range of implications. These contributions are all interrelated as the complex feedback mechanisms (i.e., CO2 back infiltration from decarbonation fronts) affect fluid-mineral-melt phase relations (i.e., lowering P(H2O)) that affect gas speciation, vapour saturation and critical behaviour, metal partitioning, i.e., Au, W, Mo, etc. through to eruptive processes, including magma-volatile behaviour, eruptive dynamics, emplacement rates, etc. all of which are critical to interpreting various parts of these systems. The mass-balance analysis of various infiltrative skarns compliments this research, by detailing the proportion of material added to and (or) removed from the metasomatic system, which then constrains the degree of fluid-rock reaction associated with skarn formation, the elemental mobility (fluid-rock ratios) observed, alteration zoning produced, and the mechanisms responsible for these endo- and exo-contact reaction zones; typically infiltrative skarns form some of the richest mineral deposits due to these complex processes. The volatile fluxing and syntectic processes require a better understanding of high-T, skarn-forming processes, including H2O-CO2  infiltrative decarbonation equilibria, carbonate fluxing relations, as well as the reactions that govern differential degassing of carbonated silicate magmas and their dynamic explosive emplacement processes, including pyroclastic volcanism.