Abstract

The combined potentiality of benchtop micro X-ray fluorescence spectroscopy (μ-XRF) and micro computed tomography (μ-CT) has been applied to describe microstructures, type and distribution of mineralogical phases as well as geological constraints on the history of the North West Africa (NWA) 8657 shergottite Martian meteorite. The 3D rendering of the sample was used to compute its porosity caused by gas bubbles, infer the presence of little cracks and reveal different shapes in its crystal habits including subhedral pyroxene phases, Ca phosphates and rounded sulphide and/or sulphates structures. Phase discrimination was achieved by comparing chemical information about element distribution with mineral classes segmented as a function of their relative density. In particular, the relationships between the plagioclase/maskelynite phase and phosphates, the chemical zoning of Ca-pyroxenes and maskelynite and the presence of S-bearing phases in the form of K-sulphates and Fe-sulphides were revealed, which allowed reconstructing satisfactorily meteorite history. The successful performance of the combined approach used in this work shows promising for further application to other types of meteorites.

Articolo completo: https://www.sciencedirect.com/science/article/pii/S0039914020304057