Carmela Vaccaro

Chemical-mineralogical characterisation of clay sediments around Ferrara (Italy): a tool for an environmental analysis

Abstract The content of heavy metals in water and soil is a key parameter for evaluating the geochemical vulnerability of an ecosystem. These elements display a limited solubility and are easily trapped and adsorbed by phyllosilicate minerals; they are thus preferentially partitioned in the fine fraction of sediments. In this light, an analysis of recent river sediments gives information on possible water pollution, and more in general on the related ecosystem. We therefore investigated the chemical–mineralogical features of clay sediments outcropping around the town of Ferrara, paying particular attention to their fine fraction (grain size X-ray fluorescence (XRF) analyses indicate that the abundance of transition trace elements, such as Cr and Ni, is positively correlated with MgO wt.%, and discriminates two well-delineated populations of samples, respectively characterised by high (Cr>180 ppm; Ni>100 ppm) and low (Cr 1); on the other hand, the high-Cr samples have a coarser grain size, and a lower abundance of clay minerals in which chlorite (Mg-rich chlorite in this group of samples) predominates over smectite+mixed layers (Sm+ML/Chl An integration of similar scientific contributions would be useful to set up a geochemical–mineralogical database as a first step toward the preparation of more complete thematic maps. These would provide information relative to the behaviour (e.g. distribution and abundance) of chemical elements within the different geochemical spheres, and would be useful for recognising and interpreting possible geochemical anomalies induced by pollution processes.

Crystal chemistry and petrologic significance of Fe3+-rich phlogopite from the Tapira carbonatite complex, Brazil

Abstract This contribution deals with the crystal chemistry of phlogopite and Fe3+-rich phlogo- pite from the Tapira alkaline-carbonatite complex (Brazil) to assess the petrological significance and genetic conditions of these rocks. The Tapira complex consists of a layered intrusion composed mainly of ultramafic rocks (dunite, wehrlite, clinopyroxenite, bebedourite, gamet-magnetitite, perovskite-magnetitite, and glimmerite) with subordinate car- bonatite. The wide range of textural, optical, and crystal-chemical characteristics of phlogopite is related to the variation of fO₂, aH₂O, and aCO₂ as well as magma bulk-chemical composition during fractional crystallization. Phlogopite from alkaline-silicate rocks (ranging from dunite to bebedourite) is characterized by fairly constant Al content, moderate [4]Fe3+ substitution, and variable amounts of Ti. The [4]Fe3+ substitution, accompanied by crystals showing reverse pleochroism, increases during fractional crystallization. These features correspond to crystallization at low pressure and high and aH₂O in the presence of moderate saturation in Ti-bearing phases, Al2O3 in the magma, or both. Phlogopite from silicate-carbonatite rocks, classified as ferriphlogopite on the basis of strong reverse pleochroism related to [4]Fe3+ tetrahedral substitution, also presents low to very low Al, Fe2+, and Ti contents. These features suggest very high fO₂, H2O, and CO2 conditions in the presence of strong saturation in Ti-bearing phases as well as very low Al2O3 content in the liquid. The crystal-structure refinements of Tapira phlogopite show that Fe3+ substitutes for Si in tetrahedral sites; Fe distribution is completely disordered, so the resulting space group is C2/m. The octahedral-site composition is similar to that of phlogopite, the octahedral sites being preferentially occupied by Mg. The presence of Fe3+ in the tetrahedral sheet enlarges the whole structure. This enlargement is reflected by an increase in cell-edge lengths and a decrease in β-angle values. The increase in distortion of the tetrahedral ring (a angle up to ~ 11°) is necessary for the tetrahedral and octahedral sheets to fit together.

A human deciduous tooth and new 40Ar/39Ar dating results from the Middle Pleistocene archaeological site of Isernia La pineta, southern Italy

Isernia La Pineta (south-central Italy, Molise) is one of the most important archaeological localities of the Middle Pleistocene in Western Europe. It is an extensive open-air site with abundant lithic industry and faunal remains distributed across four stratified archaeosurfaces that have been found in two sectors of the excavation (3c, 3a, 3s10 in sect. I; 3a in sect. II). The prehistoric attendance was close to a wet environment, with a series of small waterfalls and lakes associated to calcareous tufa deposits. An isolated human deciduous incisor (labelled IS42) was discovered in 2014 within the archaeological level 3 coll (overlying layer 3a) that, according to new 40Ar/39Ar measurements, is dated to about 583–561 ka, i.e. to the end of marine isotope stage (MIS) 15. Thus, the tooth is currently the oldest human fossil specimen in Italy; it is an important addition to the scanty European fossil record of the Middle Pleistocene, being associated with a lithic assemblage of local raw materials (flint and limestone) characterized by the absence of handaxes and reduction strategies primarily aimed at the production of small/medium-sized flakes. The faunal assemblage is dominated by ungulates often bearing cut marks. Combining chronology with the archaeological evidence, Isernia La Pineta exhibits a delay in the appearance of handaxes with respect to other European Palaeolithic sites of the Middle Pleistocene. Interestingly, this observation matches the persistence of archaic morphological features shown by the human calvarium from the Middle Pleistocene site of Ceprano, not far from Isernia (south-central Italy, Latium). In this perspective, our analysis is aimed to evaluate morphological features occurring in IS42.

The southern margin of the Caribbean Plate in Venezuela: tectono-magmatic setting of the ophiolitic units and kinematic evolution

Abstract The southern Caribbean Plate margin in Venezuela consists of a W–E elongated deformed belt, composed of several tectonic units dismembered along the northern part of the South America continental Plate since the Late Cretaceous. The present review, based on petrology and tectono-magmatic significance of each unit, makes it possible to define the main geotectonic elements and to reconstruct the paleogeographic domains from Late Jurassic to Tertiary: (a) Mid-Ocean Ridge Basalt (MORB) proto-Caribbean oceanic basin (Loma de Hierro Unit); (b) oceanic plateau (Dutch and Venezuelan Islands basement); (c) rifted continental margin (Cordillera de La Costa and Caucagua–El Tinaco Units) with Within Plate Tholeiitic (WPTh) magmatism; (d) an intra-oceanic subduction zone represented by Island Arc Tholeiitic (IAT) magmatism (Villa de Cura and Dos Hermanas Units) of Early Cretaceous age; (e) an Early Cretaceous ocean–continent subduction trench filled by melange (Franja Costera); (f) a new intra-oceanic subduction zone, represented by the tonalitic arc magmatism of Late Cretaceous age (Dutch and Venezuelan Islands). Regional tectonic constraints and coherent kinematic reconstruction suggest an original “near-Mid America” location of the Jurassic–Cretaceous “proto-Caribbean” oceanic realm. From Early to Late Cretaceous one sub-continental subduction with melanges (Franja Costera Unit) and two main stages of intra-oceanic arc magmatism are recorded in the so-called “eo-Caribbean” phases. The first consists of generally metamorphosed and deformed volcano-plutonic sequences with IAT affinity (Villa de Cura and Dos Hermanas Units), probably in relation to a southeastward-dipping subduction. The second is mainly represented by generally unmetamorphosed tonalitic intrusives cutting the oceanic plateau in the Dutch and Venezuelan Islands, and related to the new intra-oceanic subduction with reverse lithospheric sinking. The latter probably marked the onset of the Aves/Lesser Antilles arc system in the Late Cretaceous.

Mantle sources of the Cenozoic Iblean volcanism (SE Sicily, Italy): Sr-Nd-Pb isotopic constraints

SummaryA wide range of relatively undifferentiated lavas, ranging in composition from quartz-tholeiites to ankaratrites, were erupted in the Iblean area (SE Sicily) during the Upper Miocene-Lower Pleistocene. New Sr-Nd-Pb isotope analyses, presented in this paper, have been used to constrain the petrogenesis of the Iblean magmas, and to characterise their sources. The results (87Sr/86Sr: 0.70271–0.70328;143Nd/144Nd: 0.51325–0.51291;206pb/204Pb: 19.25–20.00) indicate that the Iblean lavas are mantle-derived anorogenic melts, involving DM+HIMU mantle components. Isotope and trace element data suggest that magmas formed from a heterogeneous mantle source that equilibrated in the spinel-peridotite field; the Iblean melts were thus formed within the subcontinental lithosphere. The mantle source region, was originally characterised by a depleted isotopic signature (DM), and was repeatedly and variably impregnated (refertilized) by metasomatic agents of sublithospheric origin characterised by a HIMU signature.ZusammenfassungEine Vielfalt von relativ undifferenzierten Laven, die in ihrer Zusammensetzung von Quarz-Tholeiiten bis zu Ankaratriten reichen, wurden in dem Iblei-Gebiet (Südost-Sizilen) während des Oberen Miozäns — Unteren Pleistoziins eruptiert. Neue Sr-Nd-Pb Isotopenanalysen, die hier präsentiert werden, ermöglichen es, die Möglichkeiten petrogenetischer Deutung der Iblei-Magmen einzuschränken und ihre Quellen zu charakterisieren. Die Resultate (87Sr/86Sr: 0.70271–0.70328;143Nd/144Nd: 0.51325–0.51291;206Pb/204Pb: 19.25–20.00) zeigen, dass die Iblei-Laven anorogene Schmelzen aus dem Mantel sind, die DM+HIMU Komponenten umfassen. Die Isotopen- und Spurenelement-Daten zeigen, dass die Magmen aus einer heterogenen Mantelquelle stammen, die im Spinell-Peridotit-Feld equilibrierte. Die Iblei Magmen haben sich daher innerhalb der subkontinentalen Lithosphäre gebildet. Ihre Ursprungsregion im Mantel war durch eine abgereicherte Isotopensignatur (DM) charakterisiert und wurde wiederholt und in verschiedener Weise durch metasomatische Einflüsse sublithosphärischen Ursprunges imprägniert, die durch eine HIMU Signatur charakterisiert waren.

Chemical-mineralogical characterization of historical bricks from Ferrara: an integrated bulk and micro-analytical approach

Abstract In this paper we present bulk X-ray fluorescence-X-ray diffraction (XRF/XRD) and microanalytical scanning electron microscope-electron microprobe analysis (SEM-EMPA) data on historical bricks from Medieval or Renaissance buildings of Ferrara (NE Italy) to provide insights into the nature and provenance of the raw material as well as clues on the sintering techniques. Chemical data indicate that the starting materials were obtained by mixing high Cr-Ni clay and subordinate sand (both quarried from the Po river alluvial deposits) with the possible introduction of a Na-rich flux component. Thin-section observation, XRD and micro-analytical data indicate the presence of key accessory phases such as pyroxene, amphibole, epidote and rare olivine in the pre-fired mineral assemblage, confirming the utilization of the Po river sediments. Recognition of neo-formation firing phases (e.g. melilite, wollastonite), together with composition of micas, amphiboles and interstitial glasses, indicate kiln temperatures between c. 800 and 1000 °C. This provides guidelines for making new compatible and durable bricks to be utilized for restoration, and contributes to the preservation of historical masonry.

Geochemical characterization of elements in Vitis vinifera cv. Negroamaro grape berries grown under different soil managements

The present geochemical study concerns the impact of viticultural practices in the chemical composition of the grape cultivar “Negroamaro” in Apulia, a southern Italian region renowned for its quality wine. Three types of soil management (SM), two cover cropping with different mixtures, and a soil tillage were considered. For each SM, the vines were irrigated according to two irrigation levels. Chemical composition of soil and of berries of Vitis vinifera cultivar “Negroamaro” were analyzed by X-ray fluorescence, inductively coupled plasma-mass spectrometry and multivariate statistics (linear discrimination analysis). In detail, we investigated major and trace elements behavior in the soil according to irrigation levels, the related index of bioaccumulation (BA) and the relationship between trace element concentration and soil management in “Negroamaro” grapes. The results indicate that soil management affects the mobility of major and trace elements. A specific assimilation of these elements in grapes from vines grown under different soil management was confirmed by BA. Multivariate statistics allowed to associate the vines to the type of soil management. This geochemical characterization of elements could be useful to develop fingerprints of vines of the cultivar “Negroamaro” according to soil management and geographical origin.

A new look at XRD patterns of archaeological ceramic bodies

In this paper, the general rules of phase transformations in calcareous clay bodies during firing were used to estimate the equivalent firing temperature (EFT) of seventeenth century polychrome Persian haft rang tiles based on their X-ray diffraction (XRD) patterns. The novelty of this work is, however, that it handles the XRD patterns of archaeological clay bodies with principal component analysis (PCA) in order to have a new look at their firing and thermal behaviour. Statistically handling the XRD patterns, different clusters were discriminated in the clay bodies whose mineralogical composition showed various proportions of amorphous and quartz contents. The results showed interesting trends in the different clusters in terms of the EFT, quartz content and the density of the bodies. The present work uses PCA to have a new look at XRD patterns of archaeological clay bodies and, moreover, to interpret the PCA results in order to estimate the EFT of a large number of archaeological clay bodies.

Interpolation of Rainfall Through Polynomial Regression in the Marche Region (Central Italy)

Notwithstanding its small size (less than 10,000 km2), because of its varied topography, ranging from the Apennines Range (up to more than 2000 m amsl) to coastal environments, the Marche Region (the Adriatic side of Central Italy), is characterized by many different types of climate. In this region there are no fully satisfactory models to interpolate and generalize rainfall data from the 111 available meteorological recording stations; however, in this study an innovative way to interpret data linking precipitation to many topographic parameters is introduced. Based on those considerations, statistical analyses were carried out on rainfall historical series in order to assess significantly variations during the last 60 years and to create a model capable of explaining rainfall distribution based on geographical and topographic parameters. The model highlighted a significant decrease of rainfall from 1961–1990 to 1991–2016, over the whole period, in the hilly and mountainous sectors (100–200 mm), while closer to the coast the difference is slight (about 0–100 mm). The new model also highlights the presence of some outliers in the rainfall values, which may lead to a better comprehension of climatic dynamics in this area.

Saharan dust particles in snow samples of Alps and Apennines during an exceptional event of transboundary air pollution

Southern European countries are often affected in summer by transboundary air pollution from Saharan dust. However, very few studies deal with Saharan dust pollution at high altitudes in winter. In Italy, the exceptional event occurred on February 19, 2014, colored in red the entire mountain range (Alps and Apennines) and allowed to characterize the particulate matter deposited on snow from a morphological and chemical point of view. Snow samples were collected after this event in four areas in the Alps and one in the Apennines. The particulate matter of the melted snow samples was analyzed by scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDS) and by inductively coupled plasma mass spectrometry (ICP-MS). These analyses confirmed the presence of Saharan dust particle components in all areas with similar percentages, supported also by the positive correlations between Mg-Ca, Al-Ca, Al-Mg, and Al-K in all samples.