Also,X-ray diffraction studies indicate that the hematite contents in fine-earth fraction and clay fraction rise with increase in soil-forming age and that magnetite descends while maghemite ascends in content.

• X-射线衍射结果表明土壤细土和黏粒中赤铁矿含量与风化成土时间呈正比增加。 同时,土壤有磁铁矿含量减少、磁赤铁矿增加的趋势。