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

Résumé

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.