Recent Advances in the Compositional and Mapping Analysis of Iron Meteorites Using a Handheld Laser-Induced Breakdown Spectroscopy Instrument

Abstract

Analytical techniques are essential in investigating the unique features of extra-terrestrial geomaterials, and the use of in situ analytical tools is becoming increasingly common, as it facilitates a quick initial bulk chemical analysis, identification and classification. In this work, a handheld laser-induced breakdown spectroscopy (hLIBS) instrument has been used to identify the qualitative and quantitative composition, and generate compositional micro-maps, of a suite of iron meteorite samples representative of the different chemical and structural classes by analysing the spectra released from the plasma formed by the laser impact. Furthermore, the analytical performance of hLIBS was compared with that of portable X-ray fluorescence spectrometry (pXRF). The analytical precision and accuracy of the calibration curves previously built in the laboratory for a set of certified reference metal alloys was assessed, so that the same protocol could be used to measure those of the investigated iron meteorites. A good agreement was achieved between hLIBS and reference data in the quantitative estimate of the elements Fe, Ni, Co and Cu. An attempt to quantify Ga by LIBS in two classified iron meteorites was also successful.