Swelling Chlorite in a Soil of the Dominican Republic

C. I. Rich and Juan A. Bonnet
Agronomy Department, Virginia Polytechnic Institute and State University, Blacksburg, Virginia and Soils Department, Agricultural Experiment Station, University of Puerto Rico, Rio Piedras, Puerto Rico

Abstract: A 1–0·2 µm fraction from a soil in the Dominican Republic was studied by X-ray diffraction combined with solvation, cation saturation, and heat treatments. I.R., thermal (DTA, TGA) and chemical analyses were also made. This soil is saline and alkaline and its mineral composition is greatly influenced by the lacustrine parent material and poor drainage.

In addition to swelling chlorite, illite, kaolinite, carbonates and quartz are present in the 1–0·2 µm fraction. The swelling chlorite expanded to over 18 Å when Mg saturated and solvated with glycerol or water. Lower spacings with other cations and ethylene glycol were observed. 1 N HCl treatment partially removed the interlayer hydroxides in the chlorite and 6 N HCl destroyed the mineral. The mineral gave a reflection close to 14 Å up through 600°C but collapsed at higher temperatures to 10·2 Å.

Clays and Clay Minerals; May 1975 v. 23; no. 2; p. 97-102; DOI: 10.1346/CCMN.1975.0230203
© 1975, The Clay Minerals Society
Clay Minerals Society (www.clays.org)