Abstract: Fe-Mn coatings are prevalent on the red clay in North China.First,the environmental information effects of Fe-Mn coatings are analyzed.Then removal methods are proposed based on the information.Especially,Fe-Mn coatings may have a significant impact on the element geochemistry,grain size analysis and magnetic susceptibility,which are always neglected by other researchers.
After removal of Fe-Mn coatings in Gansu Chaona red clay,it is found that Fe-Mn coatings have less effects upon the distribution patterns of rare earth elements compared with the original samples,but they may cause migration of some stable elements.This shows that some Quaternary geochemical indicators are not suitable for the red clay.