The past few Mars missions, both landed and in orbit, have provided us with a wealth of knowledge about the mineralogical content of the Martian surface, which, by extension, has allowed a determination of past Martian environmental conditions. Recently, Curiosity has revealed the presence of hematite, jarosite, gypsum, halite, and carbonate on Mars. In addition, Curiosity has revealed chromium concentrations as high as 5200 ppm at Gale Crater, with an average concentration of 2984 ppm. Significantly, chromium is a strong fluorescence emitter, even trace quantities of chromium can produce Raman spectra where the signal to noise ratio is too high to obtain any usable data. Our data on chromium substituted gypsum from middle Permian Nippewalla Group (northern Oklahoma) and the Great Salt Plains (north-central Oklahoma), strongly indicate that collecting Raman spectra on Mars may not be as straight forward as previously assumed, and further instrumental modifications may be needed.
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GSA Annual Meeting in Denver, Colorado, USA - 2016
THE ANALYSES OF GYPSUM ON MARS BY RAMAN SPECTROSCOPY: POTENTIAL PITFALLS
Raman spectroscopy can provide chemical information about a sample quickly and non-destructively with little to no sample preparation, making it an ideal instrument for Mars rover missions. The ESA ExoMars planetary mission scheduled for launch in 2020 will contain a miniaturized Raman spectrometer (RLS) as part of the Pasteur payload, and NASA is independently developing two miniaturized Raman spectrometers for its 2020 mission. Raman spectrometers that are being miniaturized for future life-detection missions on Mars have similar spectral parameters to existing field portable and hand-held Raman spectrometers. These portable spectrometers offer the ability to test on Earth the robustness of Raman spectroscopy on Mars, allowing a determination of the types of data that can be collected as well as the potential pitfalls of this analytical technique. In this work, we used a portable Raman spectrometer coupled with benchtop measurements to analyze the mineralogy and biosignatures of Mars analog sites, allowing a determination of the types of data that can be collected as well as the potential problems of this analytical technique.
Raman spectroscopy can provide chemical information about a sample quickly and non-destructively with little to no sample preparation, making it an ideal instrument for Mars rover missions. The ESA ExoMars planetary mission scheduled for launch in 2020 will contain a miniaturized Raman spectrometer (RLS) as part of the Pasteur payload, and NASA is independently developing two miniaturized Raman spectrometers for its 2020 mission. Raman spectrometers that are being miniaturized for future life-detection missions on Mars have similar spectral parameters to existing field portable and hand-held Raman spectrometers. These portable spectrometers offer the ability to test on Earth the robustness of Raman spectroscopy on Mars, allowing a determination of the types of data that can be collected as well as the potential pitfalls of this analytical technique. In this work, we used a portable Raman spectrometer coupled with benchtop measurements to analyze the mineralogy and biosignatures of Mars analog sites, allowing a determination of the types of data that can be collected as well as the potential problems of this analytical technique.