Elemental fractionation in ultraviolet laser ablation sampling of igneous silicate minerals relevant to Mars

Laser ablation sampling (LAS) has significant potential for remote terrestr ial and extraterrestrial applications if fractionation can be understood an d controlled. This study focuses on acmite, albite, augite, diopside, forst erite, and labradorite, silicate minerals that are relevant to Mars, Earth, the moon, and asteroids. The minerals were sampled using a frequency-quadr upled Nd:YAG laser and the samples were deposited as films on graphite subs trates. Rutherford backscattering spectrometry and X-ray photoelectron spec troscopy measurements of the minerals and their films indicate sodium, magn esium, silicon, calcium, and iron fractionation. Oxygen fractionation was n ot indicated. A cation replacement mechanism is a potential source of fract ionation. These minerals can be easily distinguished by their film composit ions despite fractionation, indicating that ultraviolet laser ablation samp ling is feasible for silicate minerals. (C) 2000 Elsevier Science B.V. All rights reserved.