research

Water-rich fluids at pressures and temperatures of the Earth’s crust and upper mantle have the capacity to dissolve significant amounts of solid material. This allows large-scale mass transport to occur in the Earth’s interior without magma generation. One of the principal components of lithospheric, water-rich fluids is dissolved silica. Silica, which is the major network forming oxide in crystals and melts, could create a polymerized network in solution as well. The polymerization of aqueous silica could have profound effects on our understanding of metasomatism, aqueous transport of nominally insoluble elements, magma generation, and the formation of continental crust. Other components that could be incorporated into a polymerized network solute, such as alumina, will further complicate these effects, and are therefore also important to investigate. However, since SiO2 is the dominant oxide in the crust and upper mantle, the system SiO2-H2O is the simplest model of fluid-rock interaction. The aqueous solubility, speciation and polymerization of silica is therefore of primary importance in understanding and modeling fluid-rock interactions in the lithosphere.

My research aims to create a coherent thermodynamic theory of aqueous silica polymerization. To achieve this, I am using the piston cylinder apparatus to measure the solubility of quartz near the upper critical end point of the H2O-SiO2 system, and Raman spectroscopy to provide in situ structural and compositional information about aqueous silica solutions at ambient conditions and in the hydrothermal diamond anvil cell. I also run ab initio simulations to support and interpret the experimental results.

Publications

Hunt, J.D, Kavner, A., Schauble, E.A., Doltsinis, N., and Manning, C.E., 2008, Speciation of Aqueous Silica at High pH Using Raman Spectroscopy. Eos Trans. AGU, 89(52), Fall Meet. Suppl., Abstract V23F-2199.

Hunt, J.D, Kavner, A., Schauble, E.A., and Manning, C.E., 2007, Speciation of Aqueous Silica Using Raman Spectroscopy and First Principles Calculations. Eos Trans. AGU, 88(52), Fall Meet. Suppl., Abstract V23A-1224.

Hunt, J.D., Schauble, E.A., and Manning, C.E., 2007, Predicting Raman spectra of aqueous silica and alumina species in solution from first principles. Geochimica et Cosmochimica Acta, v. 71 (15), A425.

Hunt, J.D., Schauble, E.A., and Manning, C.E., 2006, Predicting Raman Spectra of Aqueous Silica and Alumina Species in Solution From First Principles. Eos Trans. AGU, 87(52), Fall Meet. Suppl., Abstract MR43C-1090.

Jon Hunt

research

Publications

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