A systematic mapping procedure based on the Modified Gaussian Model to characterize magmatic units from olivine/pyroxenes mixtures: Application to the Syrtis Major volcanic shield on Mars

摘要: Clenet et al. (2011) have developed an adapted version of the Modified Gaussian Model (MGM). The improvements allow characterization spectra olivine-pyroxene(s) mixtures, addressing both modal composition and individual minerals chemical composition. This MGM is fully automated operational with large amounts hyperspectral imaging data. Two natural cases are considered. first one Sumail massif in Oman ophiolite (Earth). Based on our approach applied to HyMap data, two contrasted lithologic units mapped: mantle, which harzburgite dominated, crust made gabbros clinopyroxene-rich cumulates, spectral variations interpreted terms pyroxenes compositions. Once this new mapping has been validated a controlled situation, we map distribution mafic assemblages across Syrtis Major volcano Mars using visible near-infrared (VNIR) - short wave infrared (SWIR) Observatoire pour la mineralogie, l'eau, les glaces l'activite (OMEGA) / Express (MEx) mosaic. Our results agreement previous work but olivine appears be more abundant than previously estimated central part volcanic edifice, especially ternary (augite, olivine, enstatite). these results, propose possible scenario for igneous (and thus thermal) evolution region. Surrounding terrains formed local heterogeneity can observed between northern southern areas Noachian crust. We also observe mineral within lavas, differentiation from common parent melt and/or progressive mantle source temperature. Key Points systematic characterize mixtures Olivine mixture detected lavas Pyroxenes compositions spanning enstatite-augite range