31st Annual Meeting of the DPS, October 1999
Session 60. Mars Surface: Spectra
Contributed Oral Parallel Session, Thursday, October 14, 1999, 2:00-3:30pm, Sala Plenaria

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[60.09] Infrared micro-spectroscopy analysis of Zagami meteorite

E. Palomba (Oss. Astronomico di Capodimonte, Napoli, Italy \& Obs. de Haute Provence du CNRS, Saint Michel l'Obs., France), L. Colangeli (Oss. Astronomico di Capodimonte, Napoli, Italy), A. Rotundi (Ist. Universitario Navale, Napoli, Italy), F. Esposito (Oss. Astronomico di Capodimonte, Napoli, Italy)

A fragment Zagami meteorite was studied by means of infrared micro-spectroscopy, searching for spectral signatures due to single mineral phases. Infrared micro-spectroscopy is a non-destructive technique, which aims at the mineralogical investigation of samples. We coupled this study with EDX (Energy Dispersive X-ray) analysis at FESEM (Field Emission Scanning Electron Microscope) facility. The operative strategy was to preserve the sample, as much as possible, in the perspective of future investigations. The Normal Zagami lithology, analysed in our work, has a mineralogical composition similar to basalts, with pyroxenes as the main components, equally distributed in augite (50%) and pigeonite (50%). Pyroxene grains are surrounded by shocked melted plagioclase (Maskelinite), due to the shock event which produced the meteorite. The average size of the major phase pyroxene grains is 0.24-0.36 mm, thus it is reasonably to expect that spots of 0.1-0.2 mm could evidence spectra due to individual grains. Infrared spectra show both high-Ca and low-Ca pyroxene spectra, with bands at 1900 and 1600 cm-1 and the major reststrahlen feature centred at 1000 cm-1. We were able to retrieve, also, the maskelinite spectrum, which shows a broad feature in the mid-infrared, indicating an amorphous nature of this mineral. The infrared diffuse reflectance spectra taken on the bulk Zagami show only the pyroxene behaviour. Elemental analysis of the different mineral modes is consistent with the mineralogy inferred by spectroscopy. For the first time we obtained spectra of individual minerals representing the mean mineral phases present in the Martian soil, as also suggested by the latest Thermal Emission Spectrometer results.

This work was supported by MURST, CNR and ASI. Ernesto Palomba received support under a contract from Osservatorio Astronomico di Capodimonte.

The author(s) of this abstract have provided an email address for comments about the abstract: palomba@cerere.na.astro.it

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