Innovative analytical methodologies to characterize original and weathered materials of extraterrestrial origin and terrestrial analogues to meteorites

335 p.Innovative analytical methodologies to characterize original and weathered materials of extraterrestrial origin and terrestrial analogues to meteoritesOne of the important parts of the exploration of the Solar Systems is the study of Extraterrestrial Materials as well as of Terrestrial Analogs in a detailed way, being necessary process studies at analog sites, field workshops, instrument and operations tests, and laboratory measurements. Terrestrial analogs are defined as materials of environments on Earth that present one or more geological or environmental conditions similar to those found on an extraterrestrial body (Moon, Mars, etc.), either current or past.This PhD thesis is our first attempt to mainly characterize terrestrial-extraterrestrial materials and terrestrial analogs to meteorites, and to test several analytical techniques (Raman spectroscopy, SEM/EDX, LIBS and GC-MS) over them, which will be used in space explorations. For this purpose, impact glass, that is, material formed by hypervelocity impact of meteorites, comets or asteroids on the Earth surface, has been studied. Concretely, Libyan Desert Glasses (LDG), found in Africa, and Darwin Glasses (DG), discovered in Australia. Also, steel slag (terrestrial analogs to meteorites) collected from factories and from forest tracks (they were used as filler decades ago) were considered.The characterization of major, minor and trace compounds, the assignation to each compound as original or formed after weathering processes as well as the identification of mineral phases of high pressures and temperatures has been an important contribution to the study of these materials. New mineral phases, organic compounds and compounds related to biological activity have been identified, compounds not mentioned so far in samples such as LDG and DG. Moreover, accelerate weathering processes by interaction with water and acids have been tested, firstly with the steel slag materials, and then, the impact glasses were evaluated with the water methodology. On the other hand, it has been performed an elemental quantification through a portable LIBS instrument using a multivariate calibration procedure. All these results have been useful to develop a complete and innovative analytical methodology to characterize extraterrestrial and terrestrial analogue materials

Innovative analytical methodologies to characterize original and weathered materials of extraterrestrial origin and terrestrial analogues to meteorites

335 p.Innovative analytical methodologies to characterize original and weathered materials of extraterrestrial origin and terrestrial analogues to meteoritesOne of the important parts of the exploration of the Solar Systems is the study of Extraterrestrial Materials as well as of Terrestrial Analogs in a detailed way, being necessary process studies at analog sites, field workshops, instrument and operations tests, and laboratory measurements. Terrestrial analogs are defined as materials of environments on Earth that present one or more geological or environmental conditions similar to those found on an extraterrestrial body (Moon, Mars, etc.), either current or past.This PhD thesis is our first attempt to mainly characterize terrestrial-extraterrestrial materials and terrestrial analogs to meteorites, and to test several analytical techniques (Raman spectroscopy, SEM/EDX, LIBS and GC-MS) over them, which will be used in space explorations. For this purpose, impact glass, that is, material formed by hypervelocity impact of meteorites, comets or asteroids on the Earth surface, has been studied. Concretely, Libyan Desert Glasses (LDG), found in Africa, and Darwin Glasses (DG), discovered in Australia. Also, steel slag (terrestrial analogs to meteorites) collected from factories and from forest tracks (they were used as filler decades ago) were considered.The characterization of major, minor and trace compounds, the assignation to each compound as original or formed after weathering processes as well as the identification of mineral phases of high pressures and temperatures has been an important contribution to the study of these materials. New mineral phases, organic compounds and compounds related to biological activity have been identified, compounds not mentioned so far in samples such as LDG and DG. Moreover, accelerate weathering processes by interaction with water and acids have been tested, firstly with the steel slag materials, and then, the impact glasses were evaluated with the water methodology. On the other hand, it has been performed an elemental quantification through a portable LIBS instrument using a multivariate calibration procedure. All these results have been useful to develop a complete and innovative analytical methodology to characterize extraterrestrial and terrestrial analogue materials

TECHNART 2017. Non-destructive and microanalytical techniques in art and cultural heritage. Book of abstracts

440 p.TECHNART2017 is the international biannual congress on the application of Analytical Techniques in Art and Cultural Heritage. The aim of this European conference is to provide a scientific forum to present and promote the use of analytical spectroscopic techniques in cultural heritage on a worldwide scale to stimulate contacts and exchange experiences, making a bridge between science and art. This conference builds on the momentum of the previous TECHNART editions of Lisbon, Athens, Berlin, Amsterdam and Catania, offering an outstanding and unique opportunity for exchanging knowledge on leading edge developments. Cultural heritage studies are interpreted in a broad sense, including pigments, stones, metal, glass, ceramics, chemometrics on artwork studies, resins, fibers, forensic applications in art, history, archaeology and conservation science. The meeting is focused in different aspects: - X-ray analysis (XRF, PIXE, XRD, SEM-EDX). - Confocal X-ray microscopy (3D Micro-XRF, 3D Micro-PIXE). - Synchrotron, ion beam and neutron based techniques/instrumentation. - FT-IR and Raman spectroscopy. - UV-Vis and NIR absorption/reflectance and fluorescence. - Laser-based analytical techniques (LIBS, etc.). - Magnetic resonance techniques. - Chromatography (GC, HPLC) and mass spectrometry. - Optical imaging and coherence techniques. - Mobile spectrometry and remote sensing

Geochemical study of the Northwest Africa 6148 Martian meteorite and its terrestrial weathering processes

The number of studies of Mars geology through the geochemical analysis of Martian meteorites has been increasing in the last years because of the amount of information that can be obtained about the planet. In this study, a Martian meteorite, the Northwest Africa 6148 nakhlite, has been analysed and characterised, as there were few studies about it. After analysing it by Raman spectroscopy and Scanning Electron Microscope–Energy Dispersive X-ray Spectroscopy coupled to the Structural and Chemical Analyser interface, augite and olivine were identified as the main mineral phases of the sample. Moreover, using the Raman bands position, both minerals’ metal proportions were estimated. This methodology used in meteorite studies provides good semi-quantitative results and can offer some advantages to other techniques. In addition, calcite was found, being associated with Earth weathering processes. Surprisingly, Co3O4 was detected in the matrix of the meteorite. This is the first time that this oxide is observed in ameteorite. Itwas not possible to determine if it is an original compound fromMars or a product of a weathering process on Earth. However, whichever the case may be, solely the presence of this cobalt oxide represents a relevant finding, as it could provide a deeper knowledge of theMartian geochemistry or the Earth weathering processes. Copyright © 2017 John Wiley & Sons, Ltd.Proyecto MINECO Retos de la Sociedad. Ref. ESP2014-56138-C3-2-

Analytical methodology to elemental quantification of weathered terrestrial analogues to meteorites using a portable Laser-Induced Breakdown Spectroscopy (LIBS) instrument and Partial Least Squares (PLS) as multivariate calibration technique

The present work is focused on the in situ quantitative analysis of Si, Al,Mg, Ca, Ba, Na, and Fe, present in weathered terrestrial analogues to meteorites (black steel slag and impact glasses), using a portable Laser Induced Breakdown Spectroscopy (LIBS) instrument. For that purpose, several standards pellets of known elemental concentrations were manufactured. The elemental and molecular homogeneity of the pellets was studied by means of Scanning Electron Microscopy coupled to Energy Dispersive X-ray spectroscopy (SEM-EDS) and Raman spectroscopy. This checkwas always made before the LIBS analysis. Univariate andmultivariate (Partial Least Squares (PLS) regression) calibration approaches on LIBS spectra were selected as initial calibration models. After a comparison between both approaches, the former was discarded due to the poor linearity of the calibration curves, and PLS regressionwas chosen to treat the LIBS spectra as themultivariate calibration approach (in the ultraviolet (UV) and infrared (IR) spectral ranges). Predictive capabilities of each calibration model were evaluated by calculating regression coefficient (r), number of PLS factors (rank), relative errors of cross validation (RMSECV), residual predictive deviation (RPD) and the Bias value. At the end, the simultaneous use of both ranges of wavelengths was demonstrated to be more fruitful rather than using the individual ones, probably due to the higher number of emission lines, number of spectral variables and the PLS latent variables for each element. Moreover, a Reference Material was used as external validation, obtaining satisfactory results in the determination of elements. The predictive ability of the PLSmodelswas evaluated on samples of Darwin Glasses (Australia), Libyan Desert Glasses (Western Desert of Egypt) and black steel slag residues (steelworks of Basque Country). The obtained results were in concordance with the range of composition measured also by X-ray Fluorescence Spectrometer (ED-XRF). Our methodology is a good, rapid, simple and cost-effective alternative for in situ analysis of these terrestrial analogues over other techniques.Proyecto MINECO Retos de la Sociedad. Ref. ESP2014-56138-C3-2-

Detection of organic compounds in impact glasses formed by the collision of an extraterrestrial material with the Libyan Desert (Africa) and Tasmania (Australia)

Impact glasses are rich silica melted formed at high temperature and pressure by the impact of an extraterrestrial body on Earth. Here, Libyan Desert glasses (LDGs) and Darwin glasses (DGs) were studied. Two non-destructive analytical techniques were used to detect and characterize organic compounds present in their inclusions: Raman spectroscopy and scanning electron microscopy coupled to energy-dispersive X-ray spectroscopy (SEM-EDS). Phytoliths, humboldtine, palmitic acid, myristic acid, oleic acid, 4-methyl phthalic acid, and S-H stretching vibrations of amino acids were identified. The presence of these particular organic compounds in such materials has not been reported so far, providing information about (a) the ancient matter of the area where the impact glasses were formed, (b) organic matter belonging to the extraterrestrial body which impacted on the Earth, or (c) even to current plant or bacterial life, which could indicate an active interaction of the LDG and DG with the surrounding environment. Moreover, the identification of fullerene allowed us to know a pressure (15 GPa) and temperatures (670 K or 1800– 1900 K) at which samples could be subjected.Proyecto MINECO Retos de la Sociedad. Ref. ESP2014-56138-C3-2-

Non-destructive characterisation of the Elephant Moraine 83227 meteorite using confocal Raman, micro-energy-dispersive X-ray fluorescence and Raman-scanning electron microscope-energy-dispersive X-ray microscopies

The application of a non-destructive analytical procedure to characterise the mineral phases in meteorites is a key issue in order to preserve this type of scarce materials. In the present work, the Elephant Moraine 83227 meteorite, found in Antarctica in 1983 and originated from 4 Vesta asteroid, was analysed by micro-Raman spectroscopy, micro-energy-dispersive X-ray fluorescence and the structural and chemical analyser (Raman spectroscopy coupled with scanning electron microscopy-energy-dispersive spectroscopy) working in both point-by-point and image modes. The combination of all these techniques allows the extraction of, at the same time, elemental, molecular and structural data of the studied microscopic area of the meteorite. The most relevant results of the Elephant Moraine 83227 were the finding of tridymite for the first time in a 4 Vesta meteorite, along with quartz, which means that the meteorite suffered high temperatures at a certain point. Moreover, both feldspar and pyroxenewere found as the main mineral phases in the sample. Ilmenite, apatite, chromite and elemental sulphur were also detected as secondary minerals. Finally, calcite was found as a weathering product, which was probably formed in terrestrial weathering processes of the pyroxene present in the sample. Besides, Raman spectroscopy provided information about the conditions that the meteorite experienced; the displacements in some feldspar Raman bands were used to estimate the temperature and pressure conditions to which the Elephant Moraine 83227 was subjected, because we obtained both low and high formation temperature feldspar.Proyecto MINECO Retos de la Sociedad. Ref. ESP2014-56138-C3-2-

Multispectroscopic methodology to study Libyan desert glass and its formation conditions

Libyan desert glass (LDG) is a melt product whose origin is still a matter of controversy. With the purpose of adding new information about this enigma, the present paper analyzes the inner part of LDG specimens and compares them with the results of LDG surfaces. An integrated analytical methodology was used combining different techniques such as Raman spectroscopy, in point-by-point and imaging modes, scanning electron microscopy with X-ray microanalysis (SEM-EDS), energy-dispersive micro X-ray fluorescence spectrometry (μ-EDXRF), electron probe micro analyzer (EPMA), and optical cathodoluminescence (Optical-CL). According to our results, flow structures of the melt and the amorphous nature of the matrix could be discerned. Moreover, the observed displacement of Raman bands, such as in the cases of quartz and zircon, and the identification of certain compounds such as coesite (the most clarifying phase of high pressures), α-cristobalite, gypsum, anhydrite, corundum, rutile, amorphous calcite, aragonite, and calcite allowed us to know that LDGs could be subjected to shock pressures between 6 and more than 30 GPa, and temperatures between 300 and 1470 °C. The differences of temperature and pressure would be provoked by different cooling processes during the impact. Besides, in most cases the minerals corresponding to high pressure and temperatures were located in the inner part of the LDGs, with some exceptions that could be explained because they were trapped subsequently to the impact; there was more than one impact or heterogeneous cooling. Furthermore, nitrogen and oxygen gases were identified inside bubbles, which could have been introduced from the terrestrial atmosphere during the meteorite impact. These data helped us to clarify some clues about the origin of these enigmatic samples.Proyecto MINECO Retos de la Sociedad. Ref. ESP2014-56138-C3-2-

TECHNART 2017. Non-destructive and microanalytical techniques in art and cultural heritage. Book of abstracts

440 p.TECHNART2017 is the international biannual congress on the application of Analytical Techniques in Art and Cultural Heritage. The aim of this European conference is to provide a scientific forum to present and promote the use of analytical spectroscopic techniques in cultural heritage on a worldwide scale to stimulate contacts and exchange experiences, making a bridge between science and art. This conference builds on the momentum of the previous TECHNART editions of Lisbon, Athens, Berlin, Amsterdam and Catania, offering an outstanding and unique opportunity for exchanging knowledge on leading edge developments. Cultural heritage studies are interpreted in a broad sense, including pigments, stones, metal, glass, ceramics, chemometrics on artwork studies, resins, fibers, forensic applications in art, history, archaeology and conservation science. The meeting is focused in different aspects: - X-ray analysis (XRF, PIXE, XRD, SEM-EDX). - Confocal X-ray microscopy (3D Micro-XRF, 3D Micro-PIXE). - Synchrotron, ion beam and neutron based techniques/instrumentation. - FT-IR and Raman spectroscopy. - UV-Vis and NIR absorption/reflectance and fluorescence. - Laser-based analytical techniques (LIBS, etc.). - Magnetic resonance techniques. - Chromatography (GC, HPLC) and mass spectrometry. - Optical imaging and coherence techniques. - Mobile spectrometry and remote sensing