Chemical composition of Martian soil and rocks: Complex mixing and sedimentary transport

Chemical compositions of Martian soil and rocks indicate complex mixing relationships. Mixing of rock and soil clearly takes place and explains some of the chemical variation because sulfur, chlorine, magnesium, and perhaps iron are positively correlated due to their control from a secondary "sedimentary" mineralogy (e.g., Mg- and possibly Fe-sulfate; Fe-oxides) that is present within the soils. Certain deviations from simple soil - rock mixing are consistent with mineralogical fractionation of detrital iron and titanium oxides during sedimentary transport.