Global mineral distributions on Mars

Abstract

Determining the mineralogy of Mars is an essential part of revealing the conditions of the surface and subsurface. A deconvolution method was used to remove atmospheric components and determine surface mineralogy from Thermal Emission Spectrometer data at 1 pixel per degree (ppd). Minerals are grouped into categories on the basis of compositional and spectral similarity, and global concentration maps are produced. All binned pixels are fit well with RMS errors of ≤0.005 in emissivity. Higher RMS errors are attributed to short wavelength particle size effects on dust‐covered surfaces. Significant concentrations (>0.10) of plagioclase, high‐Ca pyroxene, sheet silicates/high‐Si glass, and hematite are detected and display distributions consistent with previous studies. Elevated concentrations of plagioclase and high‐Ca pyroxene are consistent with basaltic surfaces and are located in low‐albedo highlands regions north of ∼45°S. Significant concentrations of plagioclase and sheet silicates/high‐Si glass and low concentrations of high‐Ca pyroxenes are consistent with andesitic surfaces and are concentrated in both southern and northern high‐latitude, low‐albedo regions. Andesitic surfaces in the southern hemisphere have a lower spectral contrast than northern surfaces. An isolated surface located in Solis Planum is spectrally distinct but compositionally similar to other surfaces interpreted to be andesitic in composition. Concentrations of olivine below the detection limit correctly identify its presence in two of three locations. Potassium feldspar, low‐Ca pyroxene, basaltic glass, olivine, sulfate, carbonate, quartz, and amphibole are not detected with confidence at 1 ppd. The results presented here indicate a predominance of volcanic compositions within Martian dust‐free surfaces.