In this paper we present the results of petrochemical study of Roman cereal millstones and relative elements made of volcanic rocks, found in various archaeological sites of Messina. Fifteen samples dating from the III century AD and one from the second, also dating from the II–III centuries AD, were characterized through archaeological, petrographic, mineralogical and geochemical approach. On the petrochemical point of view the raw materials of the studied millstones are mainlyvolcanic rock characterized by Na-alkaline affinity with intraplate geochemical signature. Only two samples belonging to the K-alkaline seires showing volcanic arc signature. Comparison with literature data of similar volcanic rocks, allowed to constrain the volcanic site of provenance. Most of the intraplate samples are mugearites and benmoreites from Mt. Etna, the other are peralkaline-trachyte from Pantelleria Island and alkaline basalt from Linosa Island. The two arc-type samples derived instead from Islands of the Aeolian Archipelago. The petrochemical study of millstones improve the archaeological research, confirming the ancient communication routes and trade networks in the Mediterranean Region and highlighted the use of volcanic rocks from Sicilian area, during the Roman period, as very important sources of raw materials for millstones.

A well-preserved volcaniclastic sequence crops out in Pleistocene marine sediments along the Tyrrhenian coastline of the Calabrian-Peloritani arc (Sicily, Italy), testifying the occurrence of Lower-Middle Pleistocene volcanic activity in Southern Tyrrhenian Sea. The presence of dominant highly vesicular and minor blocky glassy particles indicates that the volcanic clasts were originated by explosive events related to the ascent and violent emission of volatile-rich magmas accompanied by and/or alternated with hydromagmatic fragmentation due to magma-sea water interaction. Field investigations and sedimentological features of the studied volcaniclastic units suggest a deposition from sediment-water density flows. The chemical classification of the pumice clasts indicates prevalent rhyolitic and dacitic compositions with calc-alkaline to high-K calc-alkaline affinity. The geochemical features of immobile trace elements together with the presence of orthopyroxene are indicative of a provenance from an arc-type environment. The age (from 980-910 to 589 ka), the chemical composition and the evidence of subaerial explosive volcanic activity constrain the origin nature and temporal evolution of the arc-type volcanism in the Southern Tyrrhenian domain. Finally, the new information here provided contribute to a better understanding of the temporal geodynamic evolution of this sector of the Mediterranean domain.

Petrological and geochemical data of volcanic rocks from several sites of the Caltanissetta Basin (central-southern Sicily) are discussed to provide information about volcanism in the northern portion of the African plate. Volcanics occur as large isolated blocks, mainly as pillows and subordinate lava flows, enclosing sedimentary levels of marly limestones. They are packed in several Paleogene and Neogene clayey lithologies, which are correlated to the sedimentation into the Miocenic Foredeep. The age of volcanism is referable to Early Oligocene (Rupelian), as revealed relative dating of the interpillow calcareous sediments. The studied samples are transitional and poorly evolved alkali basalts. Petrographic study highlights a discrete uniformity for the most samples, with porphyritic texture characterized by olivine, clinopyroxene and plagioclase phenocrysts in a microcrystalline groundmass, composed of the same phases plus opaque minerals. Major and trace element data are poorly variable and the trends show low degree of fractional crystallization with some contribution of mineral accumulation. Abundance and ratios of incompatible elements resemble OIB-type volcanics from intraplate environment. A slightly different garnet lherzolite sources that underwent a low partial melting degree can be hypothesized for the studied rocks. The Oligocene volcanism of the Caltanissetta Basin results as different magmatic pulses intruded along lithospheric fractures originated in response to flexure and uplift of the African paleomargin, in the pre-subduction stage and then incorporated in the future Sicilian accretionary prism.

Major, trace element and Sr-Nd isotope data are reported for volcanic rocks from Linosa Island (Sicily Channel) with the aim of discussing the genesis and evolution of magmatism at the northern margin of the African plate. The volcanic rocks exposed at Linosa exhibit a transitional to mildly Na-alkaline affinity and are mainly mafic in composition (alkali basalt to hawaiite); benmoreitic to trachytic lithic clasts occur in the lowest exposed pyroclastic deposits. Magmas have been erupted between 1.06 ± 0.10 and 0.53 ± 0.07 Ma during three main cycles of activity: Paleolinosa, Arena Bianca and Monte Bandiera. Major and trace element data indicate a magma evolution by dominant fractional crystallization. However, compatible vs. incompatible element diagrams highlight distinct variation trends, which are interpreted to suggest fractional crystallisation starting from slightly different parental magmas, and separation of distinct mineral assemblages during polybaric evolution. Small variation of Sr and Nd isotope ratios indicate modest interaction with the crust. As other mafic magmas in Eastern Sicily and Sicily Channel (Etna, Iblei, Pantelleria, Sicily Channel seamounts), the most primitive magmas at Linosa are characterised by enrichments in high-field-strength elements (Nb, Ta) and depletion in Rb, Cs and other large ion lithophile elements. Their isotopic signatures fall close to the field of the so-called EAR (European Asthenospheric Reservoir) and FOZO (Focus Zone) mantle compositions. However, there are many significant geochemical and isotopic differences among various volcanoes in Eastern Sicily and Sicily Channel, which suggest variable degrees of melting at different depths of a heterogeneous mantle source. Overall, radiogenic isotope signatures reflect mixtures between EAR-FOZO and DMM (Depleted MORB Mantle) and may be related to mixing of asthenosphere-lithosphere or to variably metasomatised lithospheric mantle.

The Aspromonte Massif (southern Calabria, Italy) consists of an Alpine crystalline nappe pile, belonging to the southern Sector of the Calabrian Arc. The Aspromonte Unit, forming the bulk of the Massif, is overlain by the Stilo Unit and overlies, near Cardeto and Africo, phyllites and micaschists. Structural analysis on the Cardeto metapelites emphasized three deformation phases. Abundant "pin-prick" garnets characterize the fine-grained phyllites, porphyroblasts and "pin-prick" crystals are present in the micaschists. Garnets are almandine-rich with a low Mg content and variable amount of spessartine and grossular, depending on the rock composition. The porphyroblastic garnets are strongly zoned and exhibit distinctive bell-shaped Mn profiles typical of a prograde growth. The pinprick garnets show the same composition as the rims of the porphyroblastic crystals of the same sample, suggesting a late stage growth with respect to the porphyroblasts. Phengitic white mica and chlorite composition suggest crystallization under relatively-high pressure conditions. Physical conditions, inferred using chlorite-garnet geothermometer and modelled P-T pseudosections in the MnNCKFMASH system for chemically similar metapelites, suggest P in the range of 7.5-10 kbar, in the T range of 500-550 degrees C. The widespread biotite-free chlorite+almandine assemblage suggests a crystallization of almandine prior to biotite, as happens in the Sanbagawa metamorphic region of Japan, where the chlorite, garnet, biotite+albite and biotite+oligoclase assemblages at increasing temperature, indicate a P/T ratio intermediate between the blueschist facies and the Barrovian greenschist facies conditions. High pressure conditions have never been estimated in the Variscan metamorphism of the Southern Sector of the Calabrian Arc, which, instead, is characterized by medium-low P/T ratio. Only the Aspromonte Unit, tectonically overlying the Cardeto metamorphics, shows a pervasive Alpine overprint, which is characterized by a higher PIT ratio than that of the Variscan metamorphism. Consequently, we assume that the Cardeto metapelites were probably affected by an Alpine metamorphic event. Owing to the similar structural position, the Cardeto rocks could represent the Calabrian part of the Mandanici Unit, which extensively outcrops in the nearby Peloritani Mountains, that in Calabria has been overprinted by Alpine effects, but no structural or mineralogical relicts which support this interpretation have been observed. More probably, they represent a distinct Alpine tectonic unit which have experienced a relatively-high pressure Alpine (?) metamorphism and that in the Peloritani Mountains was removed from within the tectonic pile during a syn-orogenic extension episode.

The Malaguide-Ghomaride Complex is capped by Upper Oligocene-Aquitanian clastic deposits postdating early Alpine orogenesis but predating the main tectonic-metamorphic evolution, end of nappe emplacement, unroofing, and exhumation of the metamorphic units of the Betic-Rif Orogen. Two conglomerate intervals within these deposits are characterized by clasts of sedimentary, epimetamorphic, and mafic volcanic rocks derived from Malaguide-Ghomaride units and by clasts of acidic magmatic and orthogneissic rocks of unknown provenance, here studied. Magmatic rocks originated from late-Variscan two-mica cordierite-bearing granitoids and, subordinately, from aplitic dikes. Orthogneisses derive from similar plutonic rocks but are affected by an Alpine metamorphic overprint evolving from greenschist (T=510&j0;-530 degrees C and P=5-6 kbar) to low-temperature amphibolite facies (T>550&j0;C and P<3 kbar). Such a plutonic rock suite is unknown in any Betic-Rif unit or in the basement of the Alboran Sea, and the metamorphic evolution in the orthogneisses is different from (and older than) that of Alpujarride-Sebtide rocks to which they were formerly ascribed. Magmatic and metamorphic rocks very similar to those studied characterize the basements of some Kabylia and Calabria-Peloritani units. Therefore, the source area is a currently lost continental-crust realm of Calabria-Peloritani-Kabylia type, located to the ESE of the Malaguide-Ghomaride Domain and affected by a pre-latest Oligocene Alpine metamorphism. Increasingly active tectonics transformed this realm into rising areas from which erosion fed small subsiding synorogenic basins formed on the Malaguide-Ghomaride Complex. This provenance analysis demonstrates that all these domains constituted a single continental-crust block until Aquitanian-Burdigalian times, before its dispersal around nascent western Mediterranean basins.

In this fieldbook we describe the most significative Geological and petrochemical features of the Sila and Castagna Alpine tectonic Units, belonging to the Northern Sector of the Calabria-Peloritani Arc (CPA). The Sila Unit is the uppermost Alpine thrust nappe in the Northern Sector of the Arc. It consists of the three different Variscan metamorphic complexes of Gariglione, Mandatoriccio and Bocchigliero, respectively medium-high-, medium-low- and low-grade, and by the late-Variscan plutonites of the Sila Batholith. The Longobucco sequence represents the Mesozoic sedimentary cover. The Castagna Unit, underlying the Sila Unit, consists of a Variscan epi-meso-metamorphic basement intruded by late-Variscan plutonites, both re-equilibrated in Alpine time. The field-trip includes 13 stops: the first covers the Gariglione metamorphic complex; the stops from the second to the eighth are devoted to the Sila Batholith; the ninth shows the Mandatoriccio and the tenth the Bocchigliero metamorphic complexes; the eleventh and the twelfth ones show the Castagna metamorphic and plutonic basement; lastly in the thirteenth stop, some tectonic contacts and structures of the Northern Sector, of the Arc are shown in the Corace tectonic window

The Sila batholith is the largest granitic massif in the Calabria-Peloritan Arc of southern Italy, consisting of syn to post-tectonic, calc-alkaline and metaluminous tonalite to granodiorite, and post-tectonic, peraluminous and strongly peraluminous, two-mica±cordierite±Al silicate granodiorite to leucomonzogranite. Mineral 40Ar/39Ar thermochronologic analyses document Variscan emplacement and cooling of the intrusives (293–289 Ma). SiO2 content in the granitic rocks ranges from ∼57 to 77 wt%; cumulate gabbro enclaves have SiO2 as low as 42%. Variations in absolute abundances and ratios involving Hf, Ta, Th, Rb, and the REE, among others, identify genetically linked groups of granitic rocks in the batholith: (1) syn-tectonic biotite±amphibole-bearing tonalites to granodiorites, (2) post-tectonic two-mica±Al-silicate-bearing granodiorites to leucomonzogranites, and (3) post-tectonic biotite±hornblende tonalites to granodiorites. Chondrite-normalized REE patterns display variable values of Ce/Yb (up to ∼300) and generally small negative Eu anomalies. Degree of REE fractionation depends on whether the intrusives are syn- or post-tectonic, and on their mineralogy. High and variable values of Rb/Y (0.40–4.5), Th/Sm (0.1–3.6), Th/Ta (0–70), Ba/Nb (1–150), and Ba/Ta (∼50–2100), as well as low values of Nb/U (∼2–28) and La/Th (∼1–10) are consistent with a predominant and heterogeneous crustal contribution to the batholith. Whole rock δ18O ranges from ∼+8.2 to +11.7‰; the mafic cumulate enclaves have the lowest δ18O values and the two-mica granites have the highest values. δ18O values for biotite±honblende tonalitic and granodioritic rocks (9.1 to 10.8‰) overlap the values of the mafic enclaves and two-mica granodiorites and leucogranites (10.7 to 11.7‰). The initial Pb isotopic range of the granitic rocks (206Pb/204Pb ∼18.17–18.45, 207Pb/204Pb ∼15.58–15.77, 208Pb/204Pb ∼38.20–38.76) also indicates the predominance of a crustal source. Although the granitic groups cannot be uniquely distinguished on the basis of their Pb isotope compositions most of the post-tectonic tonalites to granodiorites as well as two-mica granites are somewhat less radiogenic than the syn-tetonic tonalites and granodiorites. Only a few of the mafic enclaves overlap the Pb isotope field of the granitic rocks and are consistent with a cogenetic origin. The Sila batholith was generated by mixing of material derived from at least two sources, mantle-derived and crustal, during the closing stages of plate collision and post-collision. The batholith ultimately owes its origin to the evolution of earlier, more mafic parental magmas, and to complex intractions of the fractionating mafic magmas with the crust. Hybrid rocks produced by mixing evolved primarily by crystal fractionation although a simple fractionation model cannot link all the granitic rocks, or explain the entire spectrum of compositions within each group of granites. Petrographic and geochemical features characterizing the Sila batholith have direct counterparts in all other granitic massifs in the Calabrian-Peloritan Arc. This implies that magmatic events in the Calabrian-Peloritan Arc produced a similar spectrum of granitic compositions and resulted in a distinctive type of granite magmatism consisting of coeval, mixed, strongly peraluminous and metaluminous granitic magmas.

Field and geochemical studies of granitic plutons belonging to the Serre batholith, in southern Calabria, show that some of these plutons are associated with minor molybdenite, base-metal occurrences, and granitophile geochemical anomalies. The results of a geochemical survey of granitic bedrock and treatment of the data by statistical techniques indicate a grouping of geochemically anomalous samples, with clusters of high R-mode factor scores that identify potential hosts of significant granite-related mineralization, especially Mo, Sn, and W. Especially favourable hosts are siliceous and generally potassic differentiated granitic rocks, especially near the village of San Todaro, and near Bagni di Guida, Monte Cola, Monte Crocco and Mongiana. These areas are candidates for more detailed exploration, as they contain clustering of significant geochemical anomalies for Mo, Rb, W, Cu, Nb, etc., and more importantly, these granites are known to host base-metal sulphide veins. Granite specialization indices for (Rb/Sr>5, K/Rb<200 and Rb3/Ba.Sr.K>0.1) are also typical of granitic rocks hosting base-metal and granitophile mineralization; high-factor scores for the associations K-Rb-Ba-Al-Pb, Nb-Sn, Sn-As and Cu-Sn are also found.Intrusive rocks from the Serre batholith, and from the nearby Sila batholith, in northern Calabria, have similar fluid inclusion features; both contain fluid inclusions that resemble those from granites known to show mineralization elsewhere. A common characteristic of inclusions in Sn-bearing granitic rocks and those in the Serre batholith is the correlation between homogenization temperature and salinity, suggesting mixing of magmatic saline fluids with cooler, lower salinity meteoric waters. There is no evidence, however, that vigorous, voluminous, and intense alteration by boiling and high salinity hydrothermal systems were developed in the Serre batholith, Sulphide-bearing veins near Bagni di Guida and San Todaro, two of the most important areas identified in this study as potential hosts, probably reflect episodic tectonic adjustments that momentarily dropped the pressure from lithostatic to hydrostatic, producing boiling and minor hydrothermal alteration. Known sulphide occurrences in the Serre batholith are thus unlikely to be expressions of a major hydrothermal alteration and mineralization system, unless the occurrences represent the distal effects of such a system.