The mineralogy and chemical compositions of shale and sandstone alternations of Cretaceous age of the Monte Soro Unit, Sicily, have been determined. The clay minerals in the shales are mostly illite and I-rich mixed-layer I/S reflected by enrichment in Al₂O₃, K₂O, and chemically similar elements. The sandstones are subarkose to quartz arenite. The shales and sandstones have upper-crustal rare earth element patterns, and except for K₂O, they are depleted in alkaline and alkaline-earth elements as a result of intense weathering. The sandstone and shale mineralogy suggests a diagenetic history in which the sediments were subjected to temperatures in excess of 100°C, during which interaction between some minerals in the shales and sandstones took place. Thus, diagenetic quartz cementation and feldspar alteration in the sandstones and smectite illitization in the shales occurred together with the shales being a sink for potassium and the sandstones a sink for silicon. Negative europium anomalies ( between 0.45 and 0.87), (Gd/Yb)_ch ratios (<2, except for sample C1), and Sc/Cr versus La/Y and La-Th Sc diagrams suggest that the sedimentary rocks were derived from post-Archean granitoid-like rocks in a tectonically stable area. In addition, the foliated fabrics of polycrystalline quartz grains and the abundant phyllite rock fragments indicate a provenance from metamorphic rocks. The study of several trace element ratios (Ti/Zr, Cr/Zr, Y/Ni, Cr/V, Zr/Th, La/Th, La/Th, Cr/Th, Zr/Hf, Zr/Yb, Yb/Hf, V/La, La/Yb) strongly supports a local derivation from the European paleomargin.

Volcanic rocks have been used for building activity by the inhabitants of important cities located on the slopes of Mt. Etna, Italy. In this paper, the potential use of volcanic residues (code 20 03 03—“Municipal waste” residues from road cleaning in the European Waste Catalogue (EWC)) for the production of alkali activated material, especially devoted to the restoration of buildings belonging to the Baroque Sicilian architecture, was investigated. In particular, large volcanic pyroclastic deposits of recent eruptions considered waste materials were studied and a volcanic paleo-soil, locally named ghiara, widely used for mortars and plaster production in XVII–XVIII century with good pozzolanic features, was also considered. Both volcanic materials were activated using different mixtures of NaOH and Na₂SiO₃. Furthermore, formulations with different amount of metakaolin addition (10–25 wt%) were prepared due to low reactivity of volcanic materials and to allow the activation at room temperature. X ray diffraction revealed the formation of small quantities of zeolites as a result of the alkali activation process. The mechanical-physical results evidenced that the mechanical strength is strongly dependent on the metakaolin amount (10–38 MPa); accessible porosity average 25% and an average pore diameter of 0.06 µm; water absorption range 9–15%, eluates conductivity in the range 20–350 µS/m. These results confirm the occurring of alkali activation and the good potential for these pyroclastic wastes for valorization in the restoration field. Graphic

Mesozoic mudrocks and sandstones from the Longobucco Group (Sila Unit, North Calabria) were mineralogically, chemically, and petrographically analyzed for their burial, diagenesis, and sourcearea weathering histories. These sediments mark an important phase of the regional geological evolution along internal domains of the circum-Mediterranean chains from the Gibraltar Arc (Spain and Morocco) to the Calabria-Peloritani orogen (Italy). The effects of diagenesis on quartzose sandstone-mudstone lithotypes in the Mesozoic Longobucco Group succession are quantified. The basal Longobucco Group consists of continental clastic redbeds deposited in a rapidly subsiding rift-valley basin, overlain by shallow-marine to deep-marine carbonate and clastic strata. These sediments were analyzed using thin-section petrography, SEM/EDS, X-ray diffraction (XRD), and fluorescence. Quartzarenites display heterogeneous distributions of authigenic quartz, kaolin, illite, feldspar, and minor carbonate cementation. Authigenic zone...