Characterization of Etnean soils and application to Mars

We present the results of a study of some petromineralogical, chemical, and spectral properties of Etnean palagonitic soils. These soils exhibit highly variable mineralogy although they are considered among the best candidates as Martian soil analogs. Five specimens of Etnean volcanic soil were collected at different altitudes. Four of these are weathered and reworked pyroclasts from the historic eruptive activity; the fifth represents an ancient paleosoil (5420-2370 years B.P.). The chemical composition is hawaiitic. Petrography and mineralogy of grain mounts show they mainly consist of glass particles (black and red-orange) containing microphenocrystals of plagioclase, clinopyroxene, olivine, and Ti-magnetite, in order of abundance. One sample also contains rare amphiboles. IR (2.3-25 mu m) transmittance and UV-visible-near IF (0.4-2.6 mu m) diffuse reflectance spectra were obtained and compared with those of Martian dust.