Three lateritic profiles from different localities and of varying depth and degrees of development were analyzed for precious metals, platinum, palladium, iridium and gold by radiochemical neutron-activation analysis. In addition, the distribution of major, minor and other trace constituents (iron, silicon, magnesium, nickel, cobalt, chromium, copper, manganese, zinc, uranium, sodium, chlorine and scandium) was determined. Instrumental activation analysis, radiochemical analysis and conventional chemical procedures were used. The mineralogy of the samples was studied using electron microscopy. Sufficient analytical data were obtained to justify the use of molecular proportions and net changes plots, and a coefficient correlation method, in order to elucidate the geochemical behaviour of the elements during the weathering processes.