Rocco Laviano

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.

Mineralogical and chemical classification of Pleistocene clays from the Lucanian Basin (Southern Italy) for the use in the Italian tile industry

Abstract Data from literature and some representative ternary diagrams from Fiori et al. (1989) have been used to point out a more suitable use of Pleistocene clays, occurring in Lucanian and Apulian areas (Southern Italy), in the Italian tile production. The clays considered consist mainly of clay minerals (illite, smectite, chlorite and kaolinite) mixed with carbonates (calcite and dolomite), quartz and feldspars, and can be used as starting materials for the production of the so-called red bodies. From bodies of Lucanian clays, poorer in carbonates, the “cotto toscano” tiles can be directly obtained and also “stoneware” ones with the addition of a little quartz and feldspar. On the other hand, in the bodies of Apulian clays, the addition of suitable amounts of quartz, feldspars and carbonates are necessary to produce “porous single-fired” and “cotto toscano” tiles. Nevertheless, further technological testing is needed to confirm the mineralogical and chemical findings.

A multianalytical study of archaeological faience from the Vesuvian area as a valid tool to investigate provenance and technological features

The investigation was aimed at defining the compositional and structural characteristics of a group of monochrome blue faiences recovered in Pompeii to assess provenance on the basis of their technological features. Different complementary analytical techniques were used: Scanning Electron Microscopy (SEM) to investigate the morphological aspects of the samples and in particular of the interfaces, micro-Raman Spectroscopy and XRPD to identify crystalline phases and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) to assess the elemental composition due to its sensitivity to a wide range of elements and the adequate lateral resolution. Statistical data treatment of the elemental concentrations of both the ceramic bodies and the glazes allowed us to classify the objects into compositional groups and to verify the previously established archaeological hypothesis suggesting an Egyptian provenance for faience of Pompeii.

Provenance and technology of Apulian Neolithic pottery

Abstract Apulia is the best-represented region in Italy as far as archaeometric analyses of Neolithic pottery are concerned. Cross-checked use of petrological (optical microscopy), mineralogical (X-ray powder diffraction) and chemical analyses (X-ray fluorescence) have been performed, in the Dipartimento Geomineralogico of Bari University, on 375 Early to Late Neolithic (from the seventh to the fourth millennium bc) pottery samples from the Tavoliere and Murge areas. A correlated analysis of 134 samples of the main clayey deposits of the two areas was also conducted. Generally local clays were used and, in some cases, the exploitation of a range of different local fabrics has been verified. In Middle Neolithic sites, the use of non-local clay, probably imported, has been also determined. Few finished pots were actually exchanged at an inter-site scale during the Neolithic. Preparation of raw materials has shown different choices followed by ancient potters. Clays are usually more or less refined and the use of mineral temper such as sand, quartz, calcite and grog has been found. The maximum temperature reached during firing is usually between 600–700 and 850 °C. For some Middle Neolithic fine painted pottery higher temperatures have been suggested (between 850 and 1050 °C), revealing a better firing control and the use of kilns.

Methodology of a combined approach: analytical techniques to identify the technology and raw materials used in thin-walled pottery from Herculaneum and Pompeii

This study focuses on defining compositional and structural characteristics, identifying raw materials and production technology, and validating the archaeological hypothesis of a local production of thin-walled pottery (2nd cent. BC–3rd cent. AD) in the Vesuvian area. Samples investigated were analysed using OM, SEM-EDS, XRD and LA-ICPMS supported by a statistical multivariate treatment of the compositional data of the ceramic bodies. The results obtained show how an integrated approach of analytical techniques can provide answers to archaeological questions and also give a valuable insight into the exchange of raw materials and/or finished products between sites. The paper also discloses how a combined analytical methodology represents a positive step in answering the one question which remains unsolved concerning the entire ceramic production in the Vesuvian area: the provenance of the clayey raw materials used. Indeed, the massive pottery production in the Bay of Naples down the ages contrasts with the unavailability of the necessary clayey local resources.

GEOCHEMISTRY AND MINERALOGY AS INDICATORS OF PARENTAL AFFINITY FOR CENOZOIC BENTONITES: A CASE STUDY FROM S. CROCE DI MAGLIANO (SOUTHERN APENNINES, ITALY)

Abstract The major and trace element contents and mineralogical composition of Cenozoic bentonites from the southern Apennines (Italy) have been determined, for the whole-rocks and the <2 µm size-fractions, in order to constrain parental affinities. The main mineralogical and chemical differences have been recognized in eleven samples allowing them to be grouped into two distinct subsets. The differences are based on smectite abundance, occurrence or lack of detrital clay phases, different contents of Ti, Fe, Mn, K, P, Rb, Sc, V, Cr and Ni and differences in the Eu/Eu* and Ti/Al elemental ratios. These ratios indicate an affinity for felsic volcanics for the subset showing high smectite contents. The low smectite subset shows, instead, an affinity for Cretaceous-Oligocene southern Apennine shales. A similar result is obtained using the La-Th-Sc and Th-Sc-Zr/10 diagrams. We suggest that during the deposition of the southern Apennine shales, episodic volcanic events took place. These were associated with the suture stage of the Tethyan ocean that promoted accumulation of felsic ash in the related basin and the diagenetic alteration of these materials produced bentonitic layers interbedded with shales.

A systematic characterization of fibulae from Italy: from chemical composition to microstructure and corrosion processes

Fibulae from the archaeological site of Egnatia were examined with the aim of identifying types of alloys, the processes employed for their manufacturing, and outlining the corrosion products. The results obtained, by identifying the raw materials and the technological solutions used allowed us to provide convincing answers to most of the archaeological questions and confirmed the integration of Egnatia in a complex commercial network. In addition, investigations focused on the study of corrosion products, with a view to the planning of more suitable restoration and preservation strategies.

An archaeometric approach to gain knowledge on technology and provenance of Apulian red-figured pottery from Taranto

A large sampling of Apulian red-figured pottery fragments (fifth to fourth century BC) coming from Taranto (Italy) was analyzed by a multi-technique approach. The ceramic bodies’ elemental composition has been obtained by inductively coupled plasma mass spectrometry (ICP-MS), the mineralogical composition of pastes by polarized-light optical and electron microscopies (OM and SEM-EDS), and X-ray powder diffraction (PXRD). The results obtained from the statistical treatment of compositional data, combined with those driven from mineralogical composition of pastes, allow to formulate hypotheses about the provenance of the objects and the manufacturing tradition of the workshops, starting to make it possible to understand the relationships among ceramic technology, artistic expression, and workshop practice in the samples analyzed.

Integrated investigations for the characterisation of Roman lead-glazed pottery from Pompeii and Herculaneum (Italy)

A multi-analytical approach was used to investigate Roman lead-glazed ceramic artefacts from archaeological excavations at Pompeii and Herculaneum (Italy) aiming at defining the production technology of both glaze and ceramic body, by way of integrated investigations. The chemical, structural, and micro-morphological characterisations were performed using a combination of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), optical microscopy (OM), scanning electron microscopy (SEM), and micro-Raman spectroscopy. Fragments of artefacts (skyphoi, oil lamps, bowls, askoi, amphorae, krateres) of great historical and archaeological interest were sampled. LA-ICP-MS was used to determine the elemental composition by virtue of its effective lateral resolution, its ability to detect most elements and also to analyse comparably small samples. All the archaeological objects were coated with a lead-based glaze produced using a lead oxide-plus-quartz mixture, with sodium/potassium feldspars added as a flux and two different metals used: copper and iron. Two types of ceramic pastes have been identified, but chemometric techniques support the hypothesis of a Campanian provenance for the raw materials. Degradation phenomena such as the partial devitrification of the glaze, i.e. the slow structural reorganisation towards stable crystalline phases, and the leaching by mineral dissolution in the soil, were determined.

Chemical and mineralogical investigations of majolicas (16th–19th centuries) from Laterza, southern Italy

Abstract Laterza (southern Italy) was the most important town for the manufacture of Apulian majolica ceramic from the 16th century until the end of the 18th century. The Laterza majolicas have previously been subjected to only preliminary analyses. This study extends the archaeometric knowledge of the Laterza productions with mineralogical, petrographical and chemical characterizations of ceramic body, glazed coating and pigments of the majolica. A number of 16th to 19th century pottery and tile fragments of majolica have been studied and compared with clay from local and surrounding deposits. Analyses were carried out by optical microscope, scanning electron microscope, energy-dispersive spectrometry, X-ray powder diffraction, X-ray fluorescence and inductively coupled plasma. A purification process of the raw material is suggested and for some fragments, doubtfully attributed to Laterza, a different place of manufacture. Slip (‘ingobbio’) was never found under the glaze. Si, Pb and Sn are confirmed as the principal elements in the tin-glazed coatings. The differences in the glaze opacity were attributed to different manufacturing techniques and not simply the quantity of tin. The orange-yellow colour is due to a Sb-Pb compound; black to Ni with a lower amount of Co, Fe and Sb; blue to Co, As, Fe and Ni; and Mn is the pigment of the violet-brown.