Characteristics of 14 Å Clay Minerals in the B Horizons of Podzolized Soils of Alberta

S. Pawluk
Department of Soil Science, University of Alberta, Edmonton, Canada

Abstract: Recent investigations of soils from widely distributed sites reveal the presence of clay minerals with 14 Å d spacings in the B horizons of podzolized soils in Alberta. The minerals appear to be concentrated in the 2.0-0.2 micron clay fraction, the fraction less than 0.2 micron being comprised primarily of material amorphous to X-ray. Despite the presence of montmorillonite in the eluvial horizon and soil parent material only interstratified minerals of this group appear in association with the 14 Å mineral. Smaller amounts of quartz, kaolinite and illite are also noted in these B horizons.

The data available reveal that the 14 Å mineral is derived from montmorillonite and that formation occurs in situ in the B horizons.

It is apparent from the investigations conducted that weathering of associated feldspars under mildly acid conditions, releases hydrated alumina ions. These ions not only move into the interlayer regions of montmorillonite of fine clay size, where they exist in a discontinuous manner, but are also adsorbed onto the surfaces of these minerals binding adjacent particles into aggregates of coarse clay size. Adsorbed hydrated alumina hydroxy ions in the interlayer region are responsible for the observed 14 Å d spacings.

Clays and Clay Minerals; 1962 v. 11; no. 1; p. 74-82; DOI: 10.1346/CCMN.1962.0110107
© 1962, The Clay Minerals Society
Clay Minerals Society (www.clays.org)