illitisaatio
Illitisation, or illitisation (Finnish: illitisaatio), is a geological process in which certain clay minerals, most commonly smectite, transform into illite during diagenesis or low-grade metamorphism. The resulting illite is a non-expandable, micaceous clay mineral with a higher potassium content in the interlayers and a higher layer charge than its precursor clays.
The process occurs under burial conditions where temperatures rise from near-surface levels to modest diagenetic ranges,
Significance in geology lies in its use as a marker of diagenetic maturation and burial history. Illite
In soils, illitisation refers to pedogenic transformation of clays toward illite as part of soil formation,