The Provenance of Sand in Mortars from Roman Villas in Ne Italy: a

The chemical- mineralogical composition of the sand fractions of mortars found in Roman villas dating from the 1st century A.C. located in Northern Italy has been investigated by optical microscopy, scanning electron microscopy plus energy dispersive spectroscopy microanalysis and x-ray diffractometry. The petrographic results on the mortar samples have been compared with mineralogical data available on recent fluvial sediments in rivers located near the archaeological sites investigated. The aim of this study was to assess the feasibility of this simple analytical approach as a useful tool in assisting in the determination of the provenance of the raw material used in Roman Age in the making of mortar for building construction purposes. Preliminary results indicate that a good correlation can be established between the mineralogical composition of the sand grains imbedded in the ancient mortars and the fluvial sand clasts present in rivers in areas nearby. This is particularly true when the river sands are characterized by distinct mineralogical markers

Non-destructive characterization of archeological Cu-based artifacts from the early metallurgy of southern Portugal

In this study, Monte Carlo (MC) simulations combined with energy dispersive X-ray fluorescence (EDXRF) spectroscopy have been used to characterize non-destructively a collection of Cu-based artifacts recovered from two archeological sites in southern Portugal: (a) the Chalcolithic E.T.A.R. site of Vila Nova de Mil Fontes and (b) the Middle Bronze Age site of Quinta do Estácio 6. The metal artifacts show a multilayered structure made up of three distinct layers: (a) brownish carbonate soil-derived crust, (b) green oxidized corrosion patina, and (c) bulk metal. In order to assess the reliability of the EDXRF-based Monte Carlo simulations to reproduce the composition of the alloy substrate in archeological bronze artifacts without the need to previously remove the superficial corrosion and soil derived patinas, EDXRF analysis together with scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) was also performed on cleaned and patina-/crust-coated areas of the artifacts. Characterization of the mineralogical composition of the corrosion products in the surface patinas was further determined by means of X-ray diffraction (XRD). Results suggest that the adopted EDXRF/Monte Carlo protocol may represent a safe and fast analytical approach in the quantitative characterization of the bulk chemical composition of Cu-based metal artifacts even in the presence of fairly thick corrosion patinas and/or soil-derived encrustations at the surface of the archeological objects

Surface orange patinas on the limestone of the Batalha Monastery (Portugal): characterization and decay patterns

Samples of orange patinas found on a limestone window tracery and an ornament of the Batalha Monastery have been investigated by X-ray micro-diffractometry (μ-XRD) and low-vacuum scanning electron microscopy coupled with energy dispersive spectrometry (LV-SEM + EDS). The aim of the study was to determine the composition of the layered patinas, assess whether they have been intentionally applied or naturally formed, and study their degradation patterns. Preliminary results revealed that the orange patinas on the window tracery and the ornament showed different compositions and appearance, suggesting distinct formation pathways. Orange patinas on the ornament, which are now showing decay and delamination patterns, mainly consisted of gypsum with hematite as a minor component, implying the possibility of an intentional application of a mixture of ochre and lime as tint plaster. Orange patinas on the window tracery show, instead, the presence of Ca-oxalates, abundant weddellite, and minor whewellite, with minor hematite suggesting the yellowish/orange color as being due to Ca-oxalate patinas imbedding soil dust airborne particles. Such patina was possibly formed naturally either by the chemical attack due to atmospheric air pollutants from traffic exhausts emissions or by bacterial activity. No delamination was observed on the window tracery sample with granular decohesion as the major decay phenomenon. A comparison was made between this patina and the so-called scialbatura, a surface yellowish coating often found by conservators on limestone and marble in ancient monuments in the Mediterranean region

Mineralogical and chemical characterization of surface orange layers on the limestone of the Monastery of Batalha, Central Portugal

Samples of orange surface patinas found on the limestone balustr ade and sculpture s of the Batalha Monastery in Portugal, have been investigated by X ray micro diffract ometry (µ XRD) and Low Vacuum Scanning Electron M icroscop y coupled with Energy Dispersive Spectromet ry (LV SEM + EDS) EDS). Aim of the study was to assess whether the orange layers have been intentionally applied or were resulting from stone weathering Preliminary results suggest that the orange layer on the surface is mainly consisted of gypsum and hematite with halite and weddellite as minor compon ents This discovery implies the possibility that such orange patina s were applied intentionally instead of having been formed naturally by decay . A comparison was made between this patina and the “scialbatura ”, a protective coating often applied by conservators on limestones and marbles in monuments

Losanga decorated Imitations of Italic Late Republican Black Gloss Tableware from South-Western Iberia: a Multi-analytical/Microchemical Characterization

Themicro-chemical/mineralogical composition of samples of grey-paste imitations of Italic Late Republican black gloss tableware displaying a particular kind of lozenge-shaped decoration (“Losanga pottery”) from Portuguese and Spanish archaeological sites in SWIberia has been analysed by BSEM + EDS, μXRD, Powder XRD, Portable XRF and μRaman spectroscopy. “Losanga” decorated ceramics have been found throughout theWestern Mediterranean. Most of the sherds display a green-brown to greyish-black engobe at the surface resembling the gloss found in Attic pottery from Classical Greece. The overall chemical, mineralogical and fossiliferous homogeneities of the ceramic paste show common features (low K-feldspar/plagioclase ratio, high Ca content, abundance of well-preserved fragments of foraminifera microfossils) that indicate low firing conditions in the kiln ranging from 650 to 900 °C. With respect to the ceramic body, analytical results confirm an enrichment in the surface gloss layer of iron, potassium and aluminium and a depletion in silicon and calcium; the very fine grain size of the surface coating suggests elutriation of iron oxide-rich clays as confirmed by the presence of magnetite, maghemite and goethite in μ-XRD scan. Chemical and mineralogical data also suggest that the firing process was performed in a 600–850 °C temperature range, adopting the well-known technique of alternating oxidizing and reducing firing conditions largely employed at the time. The analytical results, while compatible with the archaeological hypothesis of a common provenance of the raw materials for pottery production from the Guadalquivir valley workshops cannot be considered conclusive due to the similarity in the geological substrate in the two SW Iberian regions under study

The inhibition of biodegradation on building limestone by plasma etching

Plasma etching is an innovative technique that has been recently applied in the cleaning of soiled archaeological objects. This research investigated the use of low-pressure plasma etching in cleaning microbial contaminations on an oolitic limestone from an UNESCO World Heritage listed monument: the Batalha Monastery in Central Portugal. The cleaning effect was assessed by FTIR, SEM, optical microscope, and cell viability index measurement. Experimental work suggests that plasma discharge can cause rupture in the microbial cell structures and is helpful in removing microorganisms from the surface of the stone. At the macroscopic level, detachment of microbial crust was also observed in plasma etched bio-deteriorated limestone surfaces. Furthermore, plasma etching can inhibit the microbial growth by decomposing and eliminating the sugar-containing compounds on the limestones, thus eliminating a major nutrient supply for microbial metabolism and reproduction. Plasma etching can therefore be regarded as a fast and eco-friendly conservation tool for stone heritage architecture to prevent/reduce the onset of bio-colonization and biodegradation

The inhibition of biodegradation on building limestone by plasma etching

Plasma etching is an innovative technique that has been recently applied in the cleaning of soiled archaeological objects. This research investigated the use of low-pressure plasma etching in cleaning microbial contaminations on an oolitic limestone from an UNESCO World Heritage listed monument: the Batalha Monastery in Central Portugal. The cleaning effect was assessed by FTIR, SEM, optical microscope, and cell viability index measurement. Experimental work suggests that plasma discharge can cause rupture in the microbial cell structures and is helpful in removing microorganisms from the surface of the stone. At the macroscopic level, detachment of microbial crust was also observed in plasma etched bio-deteriorated limestone surfaces. Furthermore, plasma etching can inhibit the microbial growth by decomposing and eliminating the sugar-containing compounds on the limestones, thus eliminating a major nutrient supply for microbial metabolism and reproduction. Plasma etching can therefore be regarded as a fast and eco-friendly conservation tool for stone heritage architecture to prevent/reduce the onset of bio-colonization and biodegradation.European Commission H2020-MSCA-ITN-EJD, GA 76631

A multi-analytical study of egyptian funerary artifacts from three portuguese museum collections

A diachronic, multi-analytical approach combining EDXRF, µFTIR, µRaman, SEM-EDS, and Py-GC/MS has been adopted with the aim to study for the first time the painting materials used to decorate Egyptian funerary masks and sarcophagi ranging from the Late Period to the Roman Period and stored in the Archaeological National Museum (MNA) and the Carmo Archaeological Museum (MAC) of Lisbon and the Natural History Museum of the University in Oporto (MNH-FCUP). Results indicate that yellow and red ochres, realgar, cinnabar, Egyptian blue, and Egyptian green were used as pigments while chalk served as the preparatory layer. Over the 1000-year time-line of the studied artifacts, the palette remained remarkably consistent with previous findings as exemplified by cinnabar being used for red pigments in samples only dated after the Ptolemaic period. The presence of Sn in Egyptian blue and Egyptian green pigments used in one sample sug-gests the use of recycled bronze scraps during pigment production. Black pigments in two Late Period masks were found to be produced by mixing Egyptian blue with red ochre suggesting either a hitherto unknown method for production of purple pigments in the Egyptian palette or, alterna-tively, an attempt to create a specific hue or shade of dark brown or black. The results of this study contribute to further expand the database of Ancient Egyptian painting materials while at the same time helping to valorize three important Egyptian collections in Portugal

White Spots on Smoke Rings by Bruce Nauman: A Case Study On Contemporary Art Conservation Using Microanalytical Techniques

The artwork “Smoke Rings: Two Concentric Tunnels, Non-Communicating” by Bruce Nauman represents a case study of corrosion of a black patina-coated Al-alloy contemporary artwork. The main concern over this artwork was the widespread presence of white spots on its surface. Alloy substrate, patina, and white spots were characterized by means of energy-dispersive X-ray fluorescence and scanning electron microscopy with energy-dispersive spectroscopy. Alloy substrate was identified as an aluminum alloy 6,000 series Al–Si–Mg. Patina’s identified composition confirmed the documentation provided by the atelier. Concerning the white spots, zircon particles were found on patina surface as external elements