Zeolites occurrences prognostic using image spectral analysis in the volcanic sequences of Pequenos Lembombos, Mozambique

Abstract

The research aims at evaluating the mineral potential of the basaltic lavas of the Movene Formation, to host microcrystalline zeolites. In order to attain this goal the methods of digital image processing, geological traversing and mineralogical analysis are used in an integrated approach. Landsat 8 images were processed using standard tools such as color composite, band ratios and supervised classification methods to understand the geology of the area and to identify areas spectrally similar to the minerals studied. The interpretation of the digital elevation model allowed to reveal structures and their combined use with the color compositions facilitated the lithologic discrimination. Fieldworks were carried out in the areas with the highest exposure of the basaltic lavas to identify and sample the zeolites. Finally, the collected samples were analyzed by X-ray diffraction in order to determine mineral composition. The study increased the existing geological knowledge about this important industrial mineral, mapping five mineral occurrences and revealing the most promising areas to host this type of deposits. Favorable sectors are circumscribed to the northern part of the working area, and they are generally in the proximity of rhyolites-basalts contact. The following mineral phases were also identified: heulandite-clinoptilolite, mesolite, mordenite, stilbite and laumontit