lia of prehistoric metals in the central mediterranean area a review

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A multi analytical characterization of a small bronze figurine from Gran Carro site (Bolsena Lake, Italy)

This paper presents the results of an archaeometric analysis carried out on an early Iron Age anthropomorphic figurine discovered in the area of the Gran Carro on Bolsena Lake (Latium, Italy) site, currently interpreted as a place of worship. This statuette is considered a unicum, both because of the context in which it was found and because of its stylistic characteristics similar to those of bronzes from the Nuragic civilization (Sardinia, Italy). Its discovery and the data obtained from this work provide further evidence in support of numerous previous studies suggesting the presence of trade and direct exchanges between Sardinia and southern Etruria. The research was performed through some non-destructive investigations such as Energy Dispersive X-Ray Fluorescence (EDXRF) combined with Monte Carlo Simulation (MC) and micro-invasive investigations such as Scanning Electron Microscopy coupled by Energy Dispersive Spectroscopy (SEM–EDS) and by Electron Probe Micro-Analysis (EPMA), metallography and lead isotope analyses (LIA), performed on a selected micro-fragment. The combination of non-destructive techniques (EDXRF-MCS) for the characterization of the artefact allowed us to obtain data similar to those obtained with micro-invasive surveys, further demonstrating the effectiveness of the method. The results indicate that the statuette is made of a bronze alloy and that the copper metal was extracted from Sardinian deposits

Caratterizzazione microstrutturale di nummi ufficiali e imitativi del V secolo d.C.

La riforma di Costantino del 309 d.C. introdusse il sistema monetario basato sulla moneta d’oro, con la qualecoesistevano, però, anche nominali d’argento e in leghe di rame: questi ultimi, denominati nummi, subironotra la fine del IV e il V secolo d. C. una netta riduzione ponderale in seguito alla quale raggiunsero pesi ancheinferiori al grammo. Nel presente lavoro sono stati caratterizzati un gruppo di nummi “bronzei” allo scopo dideterminarne la composizione chimica e la struttura metallurgica da correlare alla tecnologia di produzione.Sono state applicate tecniche microscopiche (SEM-EDS) su sezioni metallografiche e spettroscopiche (XRF) sucampioni integri. I dati ottenuti con le diverse tecniche evidenziano che le monete in bronzo, con alti tenori diPb, sono state prodotte per deformazione plastica di tondelli ottenuti per fusione entro matrici refrattarie.I valori percentuali delle componenti della lega Cu-Sn, con aggiunte di Pb, rientrano nell’intervallo dicomposizione di monete bronzee tardoantiche di ambito occidentale

Il ripostiglio di Cel\uf2 (Pulfero, UD)

The Cel\uf2 hoard (half XII-beginning XI century BC), along with other contemporary bronzes from the Natisone Valleys, is meaningful to understand the role of this river route during the Late Bronze Age. In a century, the Natisone Valleys see the increasing importance of their mediating role, which is emphasized by the strategic position in the middle of the routes connecting the alpine and transalpine mining regions with the Padano-Veneto sites and the Danube- Balkan districts. Initially (BM-BR1), they were involved in widespread exchanges and represented one of the many trade routes of the period. In the following phase (BR2-BF1), they are in the process of becoming preferential interlocutors up to mediate systematic and exclusive relationships between these areas at the later stage (BF2). Due to their proximity both to the alpine mining sites and the Friulian plain, the Natisone Valleys represented important crossing points for metal supply. Most of the Cel\uf2 bronzes belongs to alpine typologies and this may mean that these regions are preferred for relationships. This evidence would even be strengthened by the archaeometric analysis: the copper of some bronzes would have a south-alpine origin (Trentino Alto-Adige and Veneto), instead of that of others would have a transalpine origin (Austria and Switzerland), but, as regards the latter, there are still some doubts

The silver treasure of Marengo: silver provenancing and insights into late antiquity Roman and Gallo-Roman hoards

Lead isotopic ratios were measured on silver fragments extracted from several important objects of the hoard of Marengo. The hoard, known as the Btreasure of Marengo^, is one of the most important silver assemblages of late antiquity. It is dated to the second half of the 2nd century AD-first half of the 3rd century AD. The interpretation of the resulting isotopic data based on extended reference isotopic databases of lead/silver ores indicates that most of the analysed objects from Marengo form a rather homogeneus stock of silver metal having a signature affine to the mines of French Massif Central. One of the objects, a large belt with figures of divinity and heroes, was made of Iberian silver, and the Pb-Ag-Cu alloy present in the filling of the arm of a female statuette is rich in Sardinian lead. The results are discussed in terms of the known circulation of silver metal in the Roman Empire in the 1st and 2nd century AD. The lead isotope data are compared with available data on coeval Roman silver hoards (Notre Dame d\u2019Allen\ue7on, Berthouville, Graincourt-l\ue8s-Havrincourt, Boscoreale), circulating silver denarii, and Roman lead ingots rescued from shipwrecks in the Western Mediterranean sea. The role of the Iberian and French mines in the silver production from the 1st to the first half of the 3rd century AD is discussed

Microstructural characterization of official and imitative nummi of Vth century A.D

Metallography is an important tool that provides useful data on the fabrication technology, thermo-mechanical history of the object and on the nature of alloy employed. This research is part of a project aimed at reinforcing numismatic classification and description with chemical and microstrustural investigations. In this paper the attention has been focused on three bronze coins: Two Roman nummi struck under Arcadius/Honorius/Theodosius II in Rome (RIC, X, nn. 1271-1283, sample C9) and under Majorian in Ravenna (RIC, X, n. 2621,sample C26); the results of analyses on an italic imitation issued during the second half of V century AD are also presented, in order to evaluate possible connections between official and unofficial coins. The composition has been determined by XRF (Kevex 770) equipped whit a secondary target of Gd. The spectrometer operated at the following conditions: 55 kV, 1.00 mA. The microstructure of coins were investigated on metallographic cross-sections by light microscopy (Leica DM 100) and by SEM (Leica Cambridge Stereoscan 440) and analysed using the X-ray micro-analysis EDS (EDAX Philips) coupled to SEM. The EDS compositional profile is also obtained on the same coins to determine the element distribution and the concentration profile from the surface to the bulk. For EDS compositional profile the SEM operated at 25 kV. The semi-quantitative determination of element concentration was carried out standarless with the ZAF correction. In Tab.1 the bulk (b) and the surface (s) compositions (Wt%), determined whit EDS and XRF, are reported. The disagreement between XRF and SEM results are due to the different surface and bulk composition [2]. The high amount of Pb on the surface layer can be attributed to its preferential migration on the surface. The thickness and morphology of corrosion depend on chemical and physical properties of environment where coin was buried ; then the values obtained by SEM on the bulk (reported in tab 1) are reliable and show that specimens consist of a bronze alloy Cu-Sn with high rates of Pb. The content of Sn, shown in fig. 3, higher of 5%, identifies a western production [1, 10, 11], in contrast with what happens in the eastern mints. The micrographs show large grains flattened, evidence of the original cast microstructure with dendritic segregation; some slip lines were detected, confirming the plastic deformation (Fig 4, Fig 6, Fig 8). In Fig 5, 7, 9 BSE images show the directional preference of Pb. These characteristics can be attributed to identical production technologies for all the samples: The hypothesis is that the flans were obtained for solidification in the mold and then hammered to the desired thickness. Next, the plastic deformation could not be too strong because the Cu-Sn alloy whit an high amount of Pb is too brittle for further deformation. After being reduced in thickness, the flan was heated and coined. The process of hammering is evidenced by the shape of the grains that are not defined and polygonal but reflect a previous dendritic phase, which shows a fusion process. The presence of microsegregation zones shows the low working on metal surface after the melting process. XRF technique, instead, has not delivered the expected results in this work; in fact, the obtained data do not reflect the true composition of the sample but only the surface's layer composition of material