After removal of the organic matter by treating the sample with 6% H2O2 at 50 °C, and removal of Fe-oxyhydroxides using dithionite– citrate–bicarbonate, eight standard treatments were applied to determine mineralogy of the clay fraction: K-saturation (KCl 1 N) followed by drying and heating at 20, 105, 300 and 550 °C, and Mg-saturation (MgCl2 1 N) followed by drying at 20 °C and saturation with ethyleneglycol (eg).