Abstract

On the basis of the previous studies, the aim of this research is to extend and detail the geological mapping of zeolitized volcanoclastic units, essentially pyroclastic and epiclastic rocks, of Mores, Bonnanaro and Torralba areas in the Eastern Logudoro. The stratigraphic succession comprise two different ignimbritic units separated by an epiclastic layer, overlain by trasgressive conglomerate which mark the base of Miocene limestones. In the most valuable sectors of this area, we produce 1:10,000 geological and zeolite grade maps (evaluated by means of XRPD analysis - Rietveld/RIR methods). The most autigenic phase is clinoptilolite, always associated with opal-CT and sometime with smectite. These minerals constitute the cement in epiclastite and unwelded pyroclastic flows and they derive from the transformation of precursor rhyolitic glass with a zeolitizzation process after deposition. The secondary mineralization was favored by hydrothermal fluids preferentially circulating through fault system. Finally, a semi-quantitative evaluation of mineral resources in these deposits is performed.

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