The stability of illite/smectite during diagenesis: An experimental study

Muscovite Dissolution at 25°C: Implications for Illite/Smectite-Kaolinite Stability Relations

“…In accord with other experimental investigations (e.g., Sass et al, 1987), a reinterpretation of the data of Mattigod and Kittrick (1979) suggests that kaolinite and a mica-like phase having the composition 0.34 K per O t0(OH)2 are the solubilitycontrolling phases in the system K20-AI203-SiO2-H20 under these conditions.…”

“…mation were calculated for several solubility-controlling, mica-like phases each coexisting with kaolinite in experimental studies with Goose Lake illite (Sass et al, 1987). Equilibrium constants (Sass et al, 1987) were used to obtain the standard free energy change for the reaction:…”

“…Equilibrium constants (Sass et al, 1987) were used to obtain the standard free energy change for the reaction:…”

“…Hemley et aL (1980) observed that muscovite is somewhat K-deficient in the relatively acid environment represented by muscovitekaolinite equilibrium. Solution equilibration studies at this phase boundary have suggested compositions of 0.9 K (Sass et al, 1987) and 0.85 K (Aja, 1989) per Copyright 9 1990, The Clay Minerals Society half cell. Furthermore, muscovite-pyrophyllite solid solutions have been synthesized at elevated temperatures (Velde and Weir, 1979;Rosenberg, 1987), which suggest that illite may be a term for the end-member of this series, with a composition of about 0.8 K per…”

Experimental Determination of the Rates of Precipitation of Authigenic Illite and Kaolinite in the Presence of Aqueous Oxalate and Comparison to the K/Ar Ages of Authigenic Illite in Reservoir Sandstones

“…Huang et al (1986) synthesised illite and kaolinite following HC1 dissolution of feldspar at 200~ and derived a model for illite and kaolinite authigenesis based on closed system titration of acidic fluids by feldspar. Sass et al (1987) and Aja et al (1991) re-examined illite and illite/smectite stability by a solubility study of natural illite-bearing assemblages between 60~ and 250~ Chermak and Rimstidt (1990) performed a kinetic investigation of the alteration of kaolinite to illite in KCI solution between 250~ and 307~ and monitored the reaction by variation in quench pH. Nagy et al (1991) measured kaolinite dissolution and precipitation rate at 80~ using a flow cell apparatus, where precipitation of kaolinite was inferred from comparison of input and output fluid composition.…”