Edafología. Volumen 7-3. Septiembre 2000. pág 143-150.
The spectral and magnetic properties of Martian soils seem to be determined mainly by two iron oxides: hematite (a -Fe2O3) and a ferrimagnetic phase that is probably maghemite (g -Fe2O3). The latter generally forms by dehydroxylation of lepidocrocite (g -FeOOH); substantial amounts of lepidocrocite may thus have been formed in Mars. Our experiments suggest that the abundance of phosphorus in Martian rocks might be crucial in favouring the formation of lepidocrocite instead of goethite (a -FeOOH), the common polymorph in Earth. Moreover, the thermal transformation products of P-doped lepidocrocites show magnetic and spectral properties consistent with those of Martian soils
Key words: Mars soils, iron oxides, reflectance spectroscopy, magnetism.