Complementary Insight from Remotely Sensed and In Situ Chemical Compositions on Mars

NASA has conducted six robotic missions to Mars: Viking, Pathfinder, Opportunity, Spirit, Phoenix and Curiosity. When comparing robotic in situ elemental abundances with bulk composition measured by the Gamma Ray Spectrometer (GRS), inconsistencies between the data arise. These issues are caused by differences in spatial resolution, difficulties in obtaining densities, and compositions of different components of the regolith. By comparing remote data with in situ estimates we can further compute accurate abundances of elements throughout the landing site regions. Results indicate that major wt% oxide values for the upper Martian crust were minimally affected spatial resolution differences, however minor elements deviated from GS derived crustal compositions. Differences between GS derived and Martian rover data ranged from 0.04 to 1.4, indicating all satellite geochemical crustal data must account for these spatial resolution differences between elements.