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[19.01] Spectral Properties of a Nitrate-Bearing Halite Rock from the Chilean Desert and Applications to Astrobiology on Mars

J. L. Bishop, K. Warren-Rhodes (SETI Institute/NASA-ARC)

This halite rock was collected in the cold and dry Chilean desert and is inhabited by bacteria. We broke open the rock and selected several fresh chips for spectroscopic and chemical analysis. This halite (NaCl) sample contains small amounts of clay and sodium nitrate, which crystallizes in the calcite structure. Visible/near-infrared (VNIR) spectra (A) and mid-IR spectra (B) are given for reflectance measurements on an internal rock chip and a fine-grained powder for comparison with Omega/Crism (A) and TES (B) spectra of Mars. Bands are observed near 4.0, 4.1, 4.5, and 4.7 µm and near 780, 800, 1390, and 1430 cm-1 (~7, 13 µm) that should uniquely identify small amounts of nitrates in powders (larger amounts in rocks) using remote spectral data. Nitrates in rocks or soil may be an indicator of current or past life and will be one of the species under investigation in analysis of spectral datasets.

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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.