Oxidized and Reduced Sulfur Observed by the Sample Analysis at Mars (SAM) Instrument Suite on the Curiosity Rover Within the Glen Torridon Region at Gale Crater, Mars

The Mars Science Laboratory (MSL) Curiosity rover has been assessing the habitability and geologic history of Gale crater, since landing in 2012. One primary objectives mission was to investigate a clay-bearing unit identified using orbital spectral data, designated Glen Torridon (GT) region. This region particular interest because its elevated abundance clay minerals that may have preserved geochemical evidence ancient habitable environments. explored GT for ∼750 sols analyzed eight drilled samples with Sample Analysis at (SAM) instrument suite evolved gas analysis-mass spectrometry. Evolved sulfur-bearing gases provided insight about composition sulfur-containing compounds Martian samples. were by three methods understand oxidation state sulfur samples: (a) SO2 evolution temperature, (b) quadratic discriminant analysis comparing SAM data SAM-like laboratory investigations, (c) isotope values from 34SO2/32SO2. results these consistent majority being an oxidized state, but two presence small amounts reduced sulfur. could variety sources represents nonequilibrium assemblage supported putative chemolithotrophic metabolisms.