New Raman–visible near‐infrared database of inorganic and mineralogical planetary and terrestrial compounds and its implications for Mars: Phyllosilicates

Abstract

The European Space Agency will launch the ExoMars Martian mission in 2020, which will study traces of water activity through the geological history of Mars, as water would mean potential presence of life. In this sense, silicates, and more concretely phyllosilicates, are among the most relevant mineral phases to be studied on the Martian surface at Oxia Planum, the selected landing site. Phyllosilicates are widely spread over the planet, together with sulfates and carbonates, in places where liquid water seems to have been present, and, therefore, knowledge about their mineralogy is of high importance. Thus, the creation of Raman and visible near‐infrared (VNIR) mineralogical databases can be critical for the interpretation of both the terrestrial analogues and the upcoming data from Mars, as Raman and VNIR spectroscopies will be on board the rovers of the ExoMars as well as of the NASA Mars 2020 missions to Mars. For that purpose, several phyllosilicates of the collection of the Geominery Museum of the Spanish Geological and Miner Institute were characterized geochemically to be used as reference. A wide number Raman and VNIR spectra of common and rare phyllosilicates were collected, and several of these are presented here.

Raman spectroscopy, assisted by X‐ray fluorescence and laser‐induced breakdown spectroscopy, to characterise original and altered mineral phases in the NWA 2975 Martian shergottite

“…The InVia spectrometer was daily calibrated setting the 520.5 cm −1 silicon line, and the Raman spectrometer band‐frequency accuracy is 1 cm −1 . The data acquisitions and treatment were performed using the Wire™ 4.2 software package by Renishaw and the RRUFF database 17 together with our own databases 18 for the identification of the compounds. The measurement parameters (laser, laser power, number of accumulations and the acquisition time of the spectra) were optimised for each analysis.…”

GeoRaman

“…Veneranda et al [26] proposes the development of the Planetary Terrestrial Analogue Library (PTAL) project, in which they provide a complete overview of 4,500 Raman spectra collected on analogue materials which have been incorporated into the PTAL database. Additionally, research by Galende et al [27] acquired a large number Raman and VNIR spectra of common and rare phyllosilicates to develop a database called Inorganic and Mineralogical Planetary and Terrestrial compounds (IMPAT-Dat).…”

Raman analyses of Al and Fe/Mg‐rich clays: Challenges and possibilities for planetary missions

“…apophyllite, pyrosmalite, hisingeriteneotocite series) were also reported using a portable spectrometer operating at 785 nm and included in Raman databases for planetary missions. 31 A series of 16 synthetic samples of smectites, with different chemical compositions, were also analysed using Raman spectroscopy with green and UV lasers and the spectra were included in published Raman spectral libraries. 32 Other studies have focused on the Raman characterisation of complex terrestrial geological samples that exhibit a mineralogy which is relevant to Mars (i.e.…”

“…Raman data for less conventional phyllosilicates (e.g. apophyllite, pyrosmalite, hisingerite–neotocite series) were also reported using a portable spectrometer operating at 785 nm and included in Raman databases for planetary missions 31 . A series of 16 synthetic samples of smectites, with different chemical compositions, were also analysed using Raman spectroscopy with green and UV lasers and the spectra were included in published Raman spectral libraries 32 …”