Diagenetic albitization of detrital K-feldspars in Jurassic, Lower Cretaceous and Tertiary clastic reservoir rocks from offshore Norway, II. Formation water chemistry and kinetic considerations.

Formation waters from clastic reservoirs offshore Norway are saturated or supersaturated with respect to albite deeper than 2.5 km. Thermodynamic and mass constraints show that the albitization process is more sensitive to potassium removal than sodium supply. Kinetic considerations indicate that at temperatures below 145°C the dissolution of K-feldspar is always faster than albite growth. Combined with replacement constraints, the kinetic data also explain the observed coarsening of growing albite crystals with increasing burial temperature. -from Authors