Multiple techniques for mineral identification of terrestrial evaporites relevant to Mars exploration

摘要: Abstract Sulfates, commonly found in evaporite deposits, were observed on Mars surface during orbital remote sensing and exploration. In terrestrial environments, precipitation creates excellent microniches for microbial colonization, especially desert areas. Deposits comprised of gypsum, calcite, quartz silicate deposits (phyllosilicates, feldspars) from Sahara Desert southern Tunisia contain endolithic colonies just below the rock surface. Previous optical observations verified presence communities and, as described this paper, spectral visible analyses have led to identification chlorophylls belonging photosynthetic bacteria. Spectral infrared region clearly detected gypsum phyllosilicates (mainly illite and/or smectite), well traces but not quartz. X-ray diffraction (XRD) analysis has identified dominant that other secondary minerals such quartz, feldspars Mg–Al-rich phyllosilicates, chlorite, smectite. The occurrence a small quantity calcite all samples was also highlighted by loss CO 2 thermal (TG–DTA). A normative calculation using XRD, data fluorescence (XRF) permitted obtain mineralogical concentration occurring samples. combination multiple techniques provides information about mineralogy rocks hence indication environments suitable supporting life