Search

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. [ABSTRACT FROM AUTHOR]

The necessity to create databases for the proper interpretation of the results obtained by the rovers that will be sent by ESA to Mars implies the study of terrestrial Martian analogues. In this work, the Meñakoz outcrops, which are basaltic volcanic rocks interbedded with Turonian sediments coming from a Cretaceous submarine volcano outcrop located in Biscay (northern Spain), have been studied and proposed as a Martian analogue. Considering that Raman and near infrared spectroscopies are two of the techniques that will go on‐board the rovers in the next planetary missions, they were used to characterize the samples collected in Meñakoz. As was expected, silicates (phyllosilicates) were the major minerals detected by those techniques in the Meñakoz samples, but also, compounds such as sulfates and oxides could be detected. Phyllosilicates are very important because they are some of the compounds that have been reported to be present on the Mars surface in previous missions and specifically in Oxia Planum, the landing site for the ExoMars 2020 rover of the ESA missions to Mars. This fact provides reasons to propose the emplacement of Meñakoz as Martian analogue. [ABSTRACT FROM AUTHOR]

During the development activities of SuperCam Calibration Target, target intended for one of the two first Raman instruments to be deployed on another planetary body, our group developed a laboratory instrument that could simulate to some extent the Raman capabilities of one of such instruments and could provide data with similar quality. The use of this kind of laboratory instruments has demonstrated its utility in the evaluation of potential calibration targets or anticipating the science outcome that an instrument could provide. The present work describes our laboratory setup to support SuperCam, evaluating similarities between both instruments, despite of differences in the hardware. Evaluation of data gathered by SuperCam on Mars and the availability of one replica of SuperCam's Calibration Target allowed the comparison on the same set of targets, demonstrating how similar Signal-to-Noise Ratio (SNR) could be achieved from both instruments. The higher energy per pulse on SimulCam is compensated by a greater analytical footprint and the use of smaller collection optics. The results show how spectra obtained at representative distances of SuperCam are comparable. Operational principles are also comparable in terms of time resolution, and close in terms of spectral resolution. This similarity has allowed different science support works using SimulCam data, as well as the support to Mars detections using our setup. We provide examples of this support that will be shared with the community in different papers, as well as examples of possible operations activities that could benefit from experiments performed with SimulCam. We show how this setup can complement the two laboratory replicas in Los Alamos and Toulouse in providing support data to different experiments. [ABSTRACT FROM AUTHOR]

Calcium sulfates are known to be potential reservoirs of organic compounds and have been detected on Mars. However, not all data that indicate the presence of sulfates collected by the Mars Exploration Rovers (Spirit and Opportunity) and Curiosity rover can be explained by the different calcium sulfate polymorphs, and therefore, mixtures of calcium sulfates with other single sulfates must be considered. In addition, the presence of mixed calcium sulfates supports the data and indicates that the molar ratio of sulfate/calcium is >1. To obtain adequate spectroscopic information of mixed-cation sulfates to be used in the interpretation of data from Mars in the next few years, the thermodynamically stable syngenite (K2Ca(SO4)2·H2O) and görgeyite (K2Ca5(SO4)6·H2O) mixed-cation sulfates have been studied along with the interrelationships in the gypsum–syngenite–görgeyite system to understand their possible formation on Mars. Raman spectroscopy and Visible–Near Infrared–Shortwave Infrared (VisNIR) spectroscopy have been used for their characterization to increase the databases for the two future Mars exploration missions, Mars2020 and ExoMars2022, where both techniques will be implemented. These VisNIR data can also help with the interpretation of spectral data of salt deposits on Mars acquired by the OMEGA and CRISM spectrometers onboard the Mars Express and Mars Reconnaissance orbiters. This work demonstrates that syngenite (K2Ca(SO4)2·H2O) easily precipitates without the need for hydrothermal conditions, which, depending on the ion concentrations, may precipitate in different proportions with gypsum. Furthermore, in this study, we also demonstrate that, under hydrothermal conditions, görgeyite (K2Ca5(SO4)6·H2O) would also be highly likely to form and may also be identified on Mars together with syngenite and gypsum. [ABSTRACT FROM AUTHOR]

Abstract: Several Finish wallpapers from the 18th and 19th century were analysed by using Raman spectroscopy assisted with EDXRF instrumentation, in an attempt of determine the pigments used in their manufacture process as well as of trying to date some of the samples through pigment composition. All pigments present in samples were determined and surprisingly the unusual and strange iron (III) chromate yellow pigment was found. Besides, unusual mixtures were found to obtain fashionable colours, especially in blue and green areas, where more than one blue pigments were mixed with green and yellow pigments. Blue verditer, ultramarine blue, Prussian blue, chrome yellow, calcite, lead white, red and yellow iron oxide, gypsum and carbon black were identified. The presence of the risky and poisonous emerald green must be highlighted. The results were compared with those found in other wallpapers from Spain and France. [Copyright &y& Elsevier]

Abstract: Paper and papyrus endurance depends on their intrinsic properties that are related to the manufacture processes and to the environmental conditions (temperature, humidity, presence of micro-organisms, etc.). During the time, paper and papyrus undergo unavoidable ageing processes causing mainly the degradation of the cellulose. In the framework of the European Project “PAPERTECH” a multi-analytical approach was selected to carefully study the behaviour, properties, and the quality of different samples of paper with different provenience, before and after artificial ageing. This work was focused to understand and explain the degradation processes occurring in paper during the time. Portable EDXRF, NMR, Raman, FTIR, ATR, mechanical properties, colour measurement and XRD analyses were performed before and after the accelerated weathering. The light and the chemical oxidation were found to cause the most aggressive ageing processes. [Copyright &y& Elsevier]

Abstract: A complete Raman and X-ray fluorescence study on the Spanish 15 cents stamp from the King Alfonso XIII (1889–1901) issue with colour error is presented. Even though this fact has been known since 1890, there is no record of such error in any catalogue. The number of printed stamps was around 1300million, and it is believed that around 4000 stamps were printed with colour error, but less than 100 stamps are known to have survived. The official colour of the 15 cents stamp was chestnut-brown violet, but due to the long period of time in which this stamp was used and due to the different printings, the differences in colour are common. All the stamps with colour error considered in this study present the same philatelic and printing technical characteristics as the standard stamps, but with chestnut-brown orange or yellow shades. As a result of the scientific analysis, the differences of the colour lie only in the use of different kinds of inks. The nature of the inks as well as the way this error happened is discussed, discarding the presence of fakes or forgeries in the stamps analysed. [Copyright &y& Elsevier]

We present the compositional analysis of three terrestrial analogues of Martian olivine-bearing rocks derived from both laboratory and flight-derived analytical instruments. In the first step, state-of-the-art spectroscopic (XRF, NIR and Raman) and diffractometric (XRD) laboratory systems were complementary used. Besides providing a detailed mineralogical and geochemical characterization of the samples, results comparison shed light on the advantages ensured by the combined use of Raman and NIR techniques, being these the spectroscopic instruments that will soon deploy (2021) on Mars as part of the ExoMars/ESA rover payload. In order to extrapolate valuable indicators of the mineralogical data that could derive from the ExoMars/Raman Laser Spectrometer (RLS), laboratory results were then compared with the molecular data gathered through the RLS ExoMars Simulator. Beside correctly identifying all major phases (feldspar, pyroxene and olivine), the RLS ExoMars Simulator confirmed the presence of additional minor compounds (i.e. hematite and apatite) that were not detected by complementary techniques. Furthermore, concerning the in-depth study of olivine grains, the RLS ExoMars simulator was able to effectively detect the shifting of the characteristic double peak around 820 and 850 cm−1, from which the Fe Mg content of the analyzed crystals can be extrapolated. Considering that olivine is one of the main mineral phases of the ExoMars landing site (Oxia Planum), this study suggests that the ExoMars/RLS system has the potential to provide detailed information about the elemental composition of olivine on Mars. Unlabelled Image • Martian rocks analogues were studied by using multiple analytical techniques. • Combined NIR and Raman results are comparable to XRD mineralogical data. • RLS Exomars Simulator results fit with those provided by the InVia spectrometer. • This work indicates that RLS can discriminate olivine having different Fo/Fa ratio. [ABSTRACT FROM AUTHOR]