Iron mineralogy and aqueous alteration on Mars from the MER Mössbauer spectrometers

The twin Mars Exploration Rovers Spirit (Gusev crater) and Opportunity (Meridiani Planum) used MIMOS II Moessbauer spectrometers to analyze martian surface materials in the first application of extraterrestrial Moessbauer spectroscopy. The instruments acquired spectra that identified the speciation of Fe according to oxidation state, coordination state, and mineralogical composition and provided quantitative information about the distribution of Fe among oxidation states, coordination states, and Fe-bearing phases. A total of 12 unique Fe-bearing phases were identified: Fe(2+) in olivine, pyroxene, and ilmenite; Fe(2+) and Fe(3+) in magnetite and chromite; Fe(3+) in nanophase ferric oxide (…

Rock paintings from Minas Gerais, Brasil, investigated by in-situ Mössbauer spectroscopy

The archaeological site of Santana do Riacho is located at about 90 km northeastern of Belo Horizonte, in the “Serra do Cipo” region. The recent development of a miniaturised Mossbauer spectrometer opened the possibility of making in-situ measurements of the rock paitings, and the results of such pioneer work is presented in this contribution. The spectrometer MIMOS II operates in backscattering geometry measuring the scattered 14.41 keV Mossbauer radiation and the 6.4 keV Fe X-rays. The dimensions of the whole instrument are approximately 110 mm (long) × 80 mm (diameter). The paintings were selected based on their colours and apparent thickness, and six spots were measured. The analysis of…

Poster contributions

On-Line and In-Situ Identification of Air Pollution

The elemental, iron-phase, and oxidation state analysis of urban aerosol samples, collected from different sites in Vitoria metropolitan region, ES, Brazil, was carried out using Mossbauer (MB) Spectroscopy (MBS) and X-ray fluorescence (XRF) techniques. A portable XRF spectrometer for elemental analysis from Na to Fe, and the miniaturized MB spectrometer MIMOS-II have been installed together using a 100 mCi 57 Co(Rh) MB source for XRF excitation. Both measurements can be performed simultaneously. For continuous and fast characterization purposes a software package was developed for Mossbauer and XRF analysis. The software is based on genetic algorithm, fuzzy logic and artificial neural netw…