Kinetics of Dissolution and Crystal Growth of Silicates and Aluminosilicates in Aqueous Solutions at Low Temperatures

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This is a continued study of the experimental determination of the dissolution and precipitation kinetics of silicates and aluminosilicates as functions of pH, temperature and the Gibbs Free Energy of reaction ( G); to examine the surfaces of the reacted minerals using surface analytical techniques (e.g. XPS, AES, STM, AFM) which when combined with rates determined from solution chemistry using flow-through reactors will provide information on surface reaction mechanisms; and to apply the rate data obtained to model low temperature, predominantly meteoric water diagenesis of a Jurassic feldspathic sandstone in the North Sea. Our experimental work is the first to describe both dissolution and precipitation rates of major rock-forming silicates and aluminosilicates as a function of G, as well as the first to measure precipitation rates in phases more complex than quartz. Incorporation of the full rate laws in an accurate two-dimensional hydrodynamic model of fluid flow in porous media should result in the first completely quantitative physical and chemical explanation of diagenesis in a dynamic sedimentary basin.