Determining olivine composition of basaltic dunes in Gale Crater, Mars, from orbit: Awaiting ground truth from Curiosity

The successful landing of the Mars Science Laboratory Curiosity rover in Gale Crater, Mars, presents a rare opportunity for validation of a spectral index developed for determining olivine chemistry from orbital midinfrared remote‐sensing data. Here, a spectral index is developed using laboratory emissivity data of 13 synthetic Mg‐Fe olivines. Utilizing this spectral index, a prediction of olivine composition (~Fo 55 ± 5 ) is made from orbital data for a NE‐SW trending dune field near the Curiosity rover. This dune field will be crossed during the mission as the rover travels toward a ~5 km‐high sediment stack (Mount Sharp) that contains orbitally detected clays and sulfates. Curiosity can use its instrument suite (ChemMin, Alpha Particle X‐ray Spectrometer, ChemCam) when it reaches the dunes to verify or refute the olivine‐chemistry prediction presented here. The ability to validate the developed spectral index using the rover's ground‐truth instruments will strengthen olivine‐chemistry mapping across the Martian surface using this spectral index.