Illitization of smectite as seen by high-resolution transmission electron microscopy
Amouric, Marc; Olives, Juan
European Journal of Mineralogy Volume 3 Number 5 (1991), p. 831 - 836
published: Oct 2, 1991
manuscript accepted: Mar 29, 1991
manuscript received: Feb 5, 1991
ArtNo. ESP147050305017, Price: 29.00 €
Abstract High-resolution transmission electron microscopy observations have been performed on a sample which represents an early stage of the transformation of smectite into illite (by hydrothermal alteration). Pure smectite (with uncollapsed layers of 1.25 nm thick), pure illite and interstratified illite-smectite have been distinguished. Detailed observations suggest the existence of two transformation mechanisms: (i) dissolution of smectite and crystallization of illite ; (ii) solid-state transformation of one smectite layer into one illite layer. Interstratified illite-smectite minerals are of random type and probably formed by a solid-state mechanism. Pure illite crystals, generally of 1 M poly type, are mainly produced by dissolution-crystallization.