Other
Scientific paper
Aug 1987
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1987gecoa..51.2103s&link_type=abstract
Geochimica et Cosmochimica Acta, vol. 51, Issue 8, pp.2103-2115
Other
3
Scientific paper
Illites from Goose Lake (Illinois) and Beavers Bend (Oklahoma) were equilibrated in 0.2 M and 2.0 M KC1 solutions with excess kaolinite and either gibbsite, boehmite, quartz, or amorphous silica. Teflonlined reaction vessels were used to heat the charges from 25° to 250°C at the vapor pressures of solution. Partial reversibility was demonstrated by approaching equilibria from both high and low K + / H + activity ratios. These experiments provide evidence for but not unequivocal proof of the attainment of equilibrium. After quenching, solutions were removed by immiscible displacement techniques and analyzed to determine the activities of H + , K + and SiO 0 2 . Ionic activities were calculated under experimental conditions using partial molal enthalpy and heat capacity data. The experimental data were used to construct isothermal, isobaric activity diagrams [log( a K + / a H + ) vs .log a SiO 2 ] for the system K 2 O-Al 2 O 3 -SiO 2 -H 2 O. Stability regions have been defined for kaolinite, boehmite and three other phases that are believed to be components of both illites. Assuming an R 2+ -free stoichiometry, these components of natural illites have 0.24, 0.67 and 0.90 K atoms per O 10 (OH) 2 representing smectite, illite and mica layers respectively. At low temperatures (<90°C) illite-smectite equilibrium is metastable with respect to calculated kaolinitemicrocline equilibrium. Between 90° and 110°C a phase transition involving illite and smectite occurs which stabilizes the assemblages illite-smectite-kaolinite and illite-smectite-microcline. This transition occurs at the same temperature as the ordering transition in natural I/S. Above 110°C the assemblage illite-smectite is again metastable with respect to kaolinite-microcline, but at 200°C and above illite and smectite may coexist stably with either kaolinite or microcline. However, smectite decomposes where a SiO 2 0 is controlled by quartz solubility yielding the stable assemblage illite-kaolinite-quartz and illite-mica-quartz.
Kittrick James A.
Rosenberg Philip E.
Sass Bruce M.
No associations
LandOfFree
The stability of illite/smectite during diagenesis: An experimental study does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The stability of illite/smectite during diagenesis: An experimental study, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The stability of illite/smectite during diagenesis: An experimental study will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1340737