where did the iron on mars come from
Mars surface color Martian dust is reddish mostly due to the spectral properties of nanophase ferric oxides (npOx) that tend to dominate in the visible spectrum. The specific npOx minerals have not been fully constrained, but nanocrystalline red hematite (α-Fe2O3) may be the volumetrically dominant one,[6] at least at the less than 100 µm sampling depth[7] of infrared remote sensors such as the Mars Express OMEGA instrument. The rest of the iron in the dust, perhaps as much as 50% of the mass, may be in titanium enriched magnetite (Fe3O4).[8] Magnetite is usually black in colour with a black streak,[9] and does not contribute to the reddish hue of dust.