9526622 Webster The proposed research will provide knowledge of the behavior of chlorine in the degassing of mafic and intermediate magmas. Projects to be undertaken include determination of: (a) the solubility of chlorine in anhydrous molten basalt and andesite as a function of major element composition, pressure and temperature, (b) the partitioning of chlorine between melt and H2O and H2O-CO2 fluids as a function of pressure from 250 to 2000 bars, and over a wide range of chlorine concentrations, and (c) chlorine partitioning between melt and apatite. Experiments will be conducted in internally heated pressure vessels, rapid-quench externally heated TXM pressure vessels and evacuated silica tubes suspended in a vertical muffle furnace. The data will be used to model the evolution of hydromagmatic fluid during crystallization of mafic magmas, to better deduce pre-eruption volatile budgets, to develop theoretical models of volcanic degassing, and to better estimate the capacity of magmatic gases to transport metals within the upper crust and volcanic edifices.
