Computer Simulation of Cation Distribution in Dioctahedral 2:1 Layer Silicates Using IR-Data: Application to Mössbauer Spectroscopy of a Glauconite Sample

Lydia G. Dainyak1, V. A. Drits2 and L. M. Heifits3
1,2 Geological Institute of the Russian Academy of Science, Moscow, Russia
3 Institute for Systems Studies of the Russian Academy of Science, Moscow, Russia

Abstract: A new approach is described to computer simulate cation distribution in octahedral sheets of dioctahedral 2:1 layer silicates with vacant trans-octahedra. This approach makes use of the information on cation distribution at the one-dimensional level provided by integrated IR optical densities for the region of OH-stretching frequencies. By using this program it is possible to show that (1) the Mössbauer spectrum of glauconite B. Patom conforms to the structural model composed of celandonite-like and illite-like domains whose dimensions are limited by approximately 2 or 4 unit cells; (2) non-equivalency of “left” and “right” cis-positions (with fixed b-direction) with respect to R2+ and R3+ occupancy is a characteristic feature of a celadonite-like domain.

Key Words: Cation distribution • Computer simulation • Glauconite • Mössbauer spectra

Clays and Clay Minerals; August 1992 v. 40; no. 4; p. 470-479; DOI: 10.1346/CCMN.1992.0400412
© 1992, The Clay Minerals Society
Clay Minerals Society (www.clays.org)