Characterization of a newly fallen Nigerian meteorite

Abstract

X-ray diffraction (XRD), Fields Emission Scanning Electron Microscope (FE-SEM) with EDS and Mossbauer Spectroscopy (MS), were applied to investigate a newly fallen solid piece of debris named the Aba Panu meteorite, after a city in south western Nigeria (Lat: N 08° 14′ 25.7″ and Long: E 003° 33′ 47.0″). Matching X-ray diffraction results, together with the FE-SEM analysis confirms the presence of four kinds of iron-bearing minerals, namely olivine, pyroxene, kamacite (Fe-Ni alloys) and troilite (FeS). The Mossbauer spectra recorded at 295 K and 78 K consist of two strong paramagnetic doublets emanating from olivine of quadrupole splitting 2.9 mm/s and pyroxene of quadrupole splitting 2.1 mm/s. These are superimposed on two magnetic sub-spectra attributed to kamacite and troilite phases. From the Mossbauer sub-spectra absorption area, the ratio of the olivine absorption area to the pyroxene absorption area indicates that the meteorite can be classified as an L-ordinary chondrite. The mole fraction of the Fe end-member of olivine (fayalite) and the orthopyroxene (ferrosilite) calculated from the EDS data will be used to identify the petrographic type of the meteorite.