Remote laser-induced breakdown spectroscopy analyses of Dar al Gani 476 and Zagami Martian meteorites

Abstract

Laser-induced breakdown spectroscopy (LIBS) was recently selected to provide active remote sensing compositional information on the Mars Science Laboratory (MSL) rover. The ability of LIBS to remotely determine differences between basaltic rock types on Mars is investigated by analyzing two Martian basaltic shergottite meteorites whose compositions differ slightly and which also differ slightly in texture. Using 14 analysis spots of ∼400 pm diameter on Dar al Gani (DaG) 476 and 9 analysis spots on Zagami, the LIBS technique at a 5.4 m standoff distance clearly distinguished the olivinephyric (DaG 476) from the basaltic (Zagami) shergottite on the basis of MgO and CaO. Mean elemental abundances agreed with literature values for these meteorites to within ∼12% for most of the major elements. The ability of LIBS to remotely distinguish between basaltic and andesitic compositions in a Martian environment was also investigated by analyzing a known andesite standard and comparing its spectra to the Martian basaltic shergottite spectra, yielding agreement with the literature andesite composition within 9%. The data presented here demonstrate the ability of LIBS to provide reasonable estimates of whole rock composition as well as determine relatively subtle differences in rock types from a distance. Copyright 2006 by the American Geophysical Union.