Fourier Transform Infrared (FTIR) Spectrographic Threshold Analysis of Serpentinite vs Stichtite: Implications for Biomarker Detection on Mars

SMSU Event Center BC

Stichtite is a chromium magnesium carbonate hydroxide mineral that forms in environments associated with the earliest life on Earth. This mineral was detectable at levels less than 5% of a sample, using Fourier Transform Infrared Spectroscopy (FTIR), a remote sensing technique which has been used to map Mars. FTIR data was collected from stichtite and its serpentinite host to capture average spectral profiles for each mineral. These endmember profiles were used to calculate synthetic profiles for a range of endmember ratios. Significantly, these synthetic profiles are an excellent match for actual measurements with stichtite-serpentinite mixtures, providing validation for the use of synthetic profiles. A synthetic profile with just 5% stichtite still displays FTIR peaks discernible from serpentinite by at least 1% reflectance intensity at wavelengths of 3500 cm-1, 1366cm-1, and 750cm-1. The association of terrestrial stichtite with early habitable environments, and its ability to be detected with a common remote sensing technique, suggest future work is needed to re-examine Mars FTIR data for the presence of a stichtite biomarker