The highest concentrations of Si[O.sub.2] (158-213 g [kg.sup.-1]) were found in the LVPF soil, which had intermediate levels of [Al.sub.2][O.sub.3] (122 to 178 g [kg.sup.-1]), whereas the LV-PG soil had the highest concentrations of [Al.sub.2][O.sub.3] (223 to 280 g kg 1) and intermediate concentrations of Si[O.sub.2] (124-139 g [kg.sup.-1]).