Lara Maritan

Archaeometric study of Etruscan-Padan type pottery from the Veneto region: petrographic, mineralogical and geochemical-physical characterisation

This multi-analytical study of Etruscan-Padan type pottery from selected localities in the Veneto region (Adria, Este, Padova and Altino, north-eastern Italy) is focused on the definition of the production areas and technological features of examined objects belonging to this ceramic class. Samples were analysed by optical and electron microscopy to study their mineralogical and structural features, with the aim of defining the nature of the paste and recognising inclusion types, and also by powder X-ray diffraction and X-ray fluorescence to determine production technology and possible provenance. Analytical data were statistically processed using traditional and non-conventional methods (non-parametric combination NPC test). To obtain further information about possible source areas of raw materials used in ceramic production, clays were also sampled in areas surrounding the archaeological sites. Some firing experiments were carried out on clays with compositions comparable with those of ceramic sherds, to define better the pyrotechnological features of the firing process used to produce the pottery.

X-ray powder diffraction clustering and quantitative phase analysis on historic mortars

This paper describes the application of cluster analysis to X-ray powder diffraction patterns (XRPD) to define homogeneous groups of mortar-based materials according to their mineralogical composition. For this purpose, the diffraction patterns of 110 samples of mortars from the Temple of Venus (Pompeii, southern Italy) were used to test the method. Rietveld refinement, for quantitative mineralogical phase analysis, was performed on the most representative sample of each cluster. The mineralogical grouping yielded by cluster analysis of XRPD data turned out to be consistent with the petrographic groups.

Trachyte from the Roman aqueducts of Padua and Este (north-east Italy): a provenance study based on petrography, chemistry and magnetic susceptibility

This study presents the results of archaeometric analysis of the stones used to build the Roman aqueduct in Padua (northeast Italy), in order to identify the petrography and the quarry/ies of provenance from which the stones were exploited. The combined approach, involving petrographic, geochemical and magnetic susceptibility data, shows that the stones used for building the Roman aqueduct were of volcanic origin, with a trachyte composition, were quarried from two different localities in the Euganean Hills (Mt. Merlo and Mt. Oliveto) and that construction of the aqueducts, particularly of its various segments, both in the present-day city centre of Padua and in the Euganean Hills area, was centralised and managed by a single authority.

Late Pleistocene/Early Holocene evidence of prostatic stones at Al Khiday cemetery, Central Sudan.

The recovery of three stone-like ovoid objects within the burial of a pre-Mesolithic (Late Pleistocene/Early Holocene) individual at Al Khiday cemetery (Central Sudan) raises the question of the nature and origin of these objects. The position in which the objects were found in relation to the human skeleton suggested a pathological condition affecting the individual, possibly urinary bladder, kidney stones or gallstones. To solve this issue, a multi-analytical approach, consisting of tomographic, microstructural and compositional analyses, was therefore performed. Based on their microstructure and mineralogical composition, consisting of hydroxylapatite and whitlockite, the investigated stones were identified as primary (endogenous) prostatic calculi. In addition, the occurrence of bacterial imprints also indicates on-going infectious processes in the individual. This discovery of the earliest known case of lithiasis extends the appearance of prostatic stones into the Late Pleistocene/Early Holocene, a disease which therefore can no longer be considered exclusive to the modern era, but which also affected prehistoric individuals, whose lifestyle and diet were significantly different to our own.

Trachyte weathering in the urban built environment related to air quality

Decay of trachyte used as building stone in urban environment was investigated through the analysis of crusts and patinas found on trachyte of the Euganean Hills in the Renaissance city walls of Padua, northeastern Italy. Mineralogical and microstructural characteristics of the alteration products, as well as major- and trace-element chemical composition, were determined by optical microscopy, SEM–EDS and X-ray mapping, XRPD, and LA-ICPMS. The results are discussed referring to environmental parameters, in particular concerning air quality and anthropic pollution sources. The influence of composition of the stone and other neighboring materials on specific weathering processes is also debated. The formation of crusts and patinas turns out to be mainly due to exogenous processes. Enrichment in heavy metals and carbonaceous matter derives from the deposition of particulate emitted during fuel combustion by road vehicles, domestic heating and, secondarily, industrial activities. The particulate is typically cemented by calcite, mainly mobilized after dissolution from nearby mortar joints, or iron, released by leaching from iron-bearing minerals, reprecipitated according to pH fluctuations. Gypsum layers were rarely observed. Generally, composition of the weathering crusts and patinas of Euganean trachyte proves to be an informative marker for the relevant environmental conditions and their evolution.

Textural and Mineralogical Analysis of Volcanic Rocks by µ -XRF Mapping

In this study, µ-XRF was applied as a novel surface technique for quick acquisition of elemental X-ray maps of rocks, image analysis of which provides quantitative information on texture and rock-forming minerals. Bench-top µ-XRF is cost-effective, fast, and non-destructive, can be applied to both large (up to a few tens of cm) and fragile samples, and yields major and trace element analysis with good sensitivity. Here, X-ray mapping was performed with a resolution of 103.5 µm and spot size of 30 µm over sample areas of about 5×4 cm of Euganean trachyte, a volcanic porphyritic rock from the Euganean Hills (NE Italy) traditionally used in cultural heritage. The relative abundance of phenocrysts and groundmass, as well as the size and shape of the various mineral phases, were obtained from image analysis of the elemental maps. The quantified petrographic features allowed identification of various extraction sites, revealing an objective method for archaeometric provenance studies exploiting µ-XRF imaging.

Raman hyperspectral imaging as an effective and highly informative tool to study the diagenetic alteration of fossil bones

Retrieving the pristine chemical or isotopic composition of archaeological bones is of great interest for many studies aiming to reconstruct the past life of ancient populations (i.e. diet, mobility, palaeoenvironment, age). However, from the death of the individual onwards, bones undergo several taphonomic and diagenetic processes that cause the alteration of their microstructure and composition. A detailed study on bone diagenesis has the double purpose to assess the preservation state of archaeological bones and to understand the alteration pathways, thus providing evidence that may contribute to evaluate the reliability of the retrieved information. On these bases, this research aims to explore the effectiveness of Raman hyperspectral imaging to detect types, extent and spatial distribution of diagenetic alteration at the micro-scale level. An early-Holocene bone sample from the Al Khiday cemetery (Khartoum, Sudan) was here analysed. Parameters related to the collagen content, bioapatite crystallinity and structural carbonate content, and to the occurrence of secondary mineral phases were calculated from Raman spectra. The acquired data provided spatially-resolved information on both the preservation state of bone constituents and the diagenetic processes occurring during burial. Given the minimal sample preparation, the easy and fast data acquisition and the improvement of system configurations, micro-Raman spectroscopy can be extensively applied as a screening method on a large set of samples in order to characterise the preservation state of archaeological bones. This technique can be effectively applied to identify suitable and well preserved portions of the analysed sample on which perform further analyses.

From clays to pots: chaînes opératoires and technical options at a burnt Late Iron Age potter’s workshop (north-eastern Italy)

The unusual discovery of a potter’s workshop suddenly destroyed by a firing-cum-collapse event at Montebello Vicentino (north-eastern Italy), dated to the Late Iron Age (ca. late fifth–fourth centuries BC), offers the unique possibility of studying two parallel operational sequences or chaines opératoires of ceramic manufacturing in this period, by direct analysis of the various base materials and products lost during destruction. Raw materials (prepared clay batch, sand, and other temper inclusions), unfired vessels knocked to the ground by the collapse, and samples of fired pottery were comprehensively characterized by petrographic and mineralogical analysis. Comparisons with similar ceramic products found at nearby settlements of Montebello can also better define the differences between production which was actually taking place at the workshop at the moment of destruction and previous work, as documented by sherds found at the same site.

The Polychrome Sinopia of Roman Mosaic at Lod (Israel): Pigments Characterization and Microstratigraphic Study

This paper presents the results of the archaeometric study on the pigments and the painting techniques used to produce the polichrome sinopia found under the tesserae of the Roman mosaic at Lod (Israel). The red, yellow, green and black paints, laying on the sovranucleus of the preparation mortar under the mosaic, were studied by polarised light microscopy on disperse pigments (PLM), reflected light microscopy (RLM), scanning electron microscopy (SEM) and X-ray powder diffraction (XRPD). The palette comprises red and yellow ochre, cinnabar, green earth and carbon black. The microstratigraphic analysis shows the presence of a carbonation layer including the pigment particles on the top of the mortars, indicating that the pigments were laid on a fresh mortar, according to a fresco technique.