Euganean trachytes: discrimination of quarried sites by petrographic and chemical parameters and by magnetic susceptibility and its bearing on the provenance of stones of ancient artefacts

This paper reports petrographic and chemical data and magnetic susceptibility values for trachytes of quarries recognizable within the Euganean Hills and sets out diagnostic parameters for these rocks. The diagnostic scheme proposed is basic for the definition of provenance of trachytes used in ancient artefacts spread over northern Italy. Trachytes were extensively used by the Romans for paving Via Aemilia, the most important road in the Po Plains connecting Ariminum (present-day Rimini on the Adriatic sea) to Placentia (present-day Piacenza on the Po river). Remains of the trachytic flagstones (basoli) used for paving segments of Via Aemilia crossing Regium Lepidi (present-day Reggio Emilia) and Bononia (present-day Bologna) have been characterised petrographically, chemically and also using magnetic susceptibility data. The discriminating scheme proposed here for the Euganean trachytes has been applied to the data obtained for basoli and thus the provenance of each investigated block has been inferred. The rocks sampled at Regium Lepidi mostly come from Monselice (only a few blocks from Monte Oliveto and Monte Merlo) and those of Bononia come mostly from Monte Merlo and, subordinately, from Monte Oliveto and Monselice (only one sample from Monte San Daniele). The dominant provenance of blocks, which is different in the two colonies distant by less than 50 km, suggests that the two segments of Via Aemilia were not built simultaneously.     

A Mössbauer study of some coloured marbles (cipollino mandolato, rosso antico and fior di pesco): implications on the nature of their colour

⁵⁷Fe Mössbauer spectroscopy permits an explanation of the formation of the iron-bearing species present in three types of coloured marbles, known as cipollino mandolato, rosso antico and fior di pesco. Structural Fe²⁺ and Fe³⁺ located in silicates, together with the remains of weakly ferromagnetic hematite, arise from primary sediments. Fe²⁺ located in carbonates and anti-ferromagnetic hematite are formed by redox processes during marble formation. The relative contents of the iron species in the three types of marbles depend on the composition of the primary sediments and on local conditions during metamorphism. Knowledge of the type and amount of the iron species in marbles may help in the reconstruction of the redox processes, which took place during marble formation. The deviations of the Morin transition of the hematites play the role of genetic indicator because purity, crystallinity and the red hues of hematites in marbles can be related to the environment of formation.     

The Russian avant-garde painting palette: Documentary and physicochemical codification of organic colorants

In the present article an attempt is made to elucidate the organic colorants commonly encountered in the Russian avant-garde painting palette by a combined art historical, documentary and physicochemical investigation, and to examine the influence of environmental factors on the chromatic profile originally sought by the artist. The overall approach based on written sources is confirmed by measurements on relevant paintings. The documentary research deals with the influences of Orthodox iconography, folkloric art, and occidental modernist tendencies on the Russian avant-garde palette, and studies the effects of contradictory historical processes in the chromatic profile of individual paintings. In the experimental section a series of colorants are investigated concerning the effects of accelerated ageing on experimental painting tables, prepared as watercolor and gouache layers on paper ground. The resulting samples are subjected to colorimetric and spectroscopic measurements, and analogous analytical procedures are applied on samples taken from selected paintings. A systematic comparative study of all data permits evaluation of the materials used in terms of their stability towards extrinsic factors, and proposal of degradation routes in order to assist museum curators and conservators in every concrete case related to the broad spectrum of pigments examined.     

Volubilis (Meknes,Morocco): Archaeometric study of the white and coloured marbles imported in the Roman age

The ruins of the Roman town of Volubilis, located in the Middle Atlas, near Meknes, between Fez and Rabat, constitute the most important Roman archaeological site in Morocco and are included in the UNESCO World Heritage List. Volubilis became the headquarters of the Mauritania Tingitana limes after the annexation of the kingdom of Mauritania to the Roman Empire in AD 42. Evacuated by the Romans after the second half of the 3rd century, the town became the capital of the kingdom of Idriss I in AD 789.The results of an archaeometric study of the marbles imported into Volubilis during the Roman age are reported herein the sixth framework program of the European Union.Of the few coloured lithotypes that have been found, all are of Greek origin with the exception of the so-called “Portuguese pink”, a pale pink marble exploited by the Romans near Vilaviçosa in the Lusitania which, till now, has not yet been identified outside Iberia. As regards the white marbles employed in the statuary, petrographic study in thin section and the δ¹³C and δ¹⁸O isotopic data emphasize the frequent use of Lunense and Pentelic marbles. The latter also features among the white marbles used for crustae and architectural elements together with the dolomitic variety of Thasian marble, Parian marble from Lakkoi, Proconnesian marble from the island of Marmara, an unknown marble most probably of local origin, and a variety of the so-called “greco scritto” whose provenance still remains unclear. In fact, its petrographic and geochemical features do not match those known for the classical “greco scritto” from Cap de Garde, near Annaba (Algeria).     

Consolidation of stone blocks prior to placement: A case study of the Roman wall in Tarragona (Spain): Report and methodology

The possible pre-consolidation of the stones used to repair the Roman wall of Tarragona was studied, on the premise that this had been carried out prior to placement in the wall. A detailed study of the stones was conducted in order to determine whether they had been treated, and if so, how this had been done. A semi-quantitative X-ray mineralogical analysis using the Rietveld method was performed, together with porosity and textural analyses. This paper concludes with a discussion of how the stones studied here were pre-consolidated using lime slurry.     

Archaeometric and geological constraints for the provenance of carbonatic breccias used in monumental works along the Flaminia Consular Road (Umbria-Marche, Central Italy)

Along the Umbria-Marche stretch of the Flaminia Consular Road (220 B.C.) several archaeological finds of the most important monumental works, are well preserved. The stones, employed to build many bridges, substructions and sewerages, are represented by carbonatic breccias whose geological environment of formation and source areas had never been established. On the basis of mineralogical, petrographic and micropalaeontological analyses, two groups of these lithotypes employed in Roman age were distinguished: “monogenic carbonatic breccias” only constituted by clasts of the Maiolica Unit (Late Jurassic – Early Cretaceous) and “polygenic carbonatic breccias” made of fragments (in different proportions) of Calcare Massiccio (Early Jurassic), Corniola (Early Jurassic), Maiolica (Late Jurassic – Early Cretaceous) and Scaglia Rossa (Late Cretaceous – Early Paleogene) Units. The possible source areas of the breccias are compatible with stratified slope-waste to scarp-base deposits of periglacial origin belonging to the Upper Pleistocene. In particular, among the seven investigated areas, we pointed out the most probable provenances (Monte Faeto-Colle, Costacciaro, Scirca, Foci, Secchiano) along the flanks of the Apennine Mesozoic chain of the Umbria and Marche regions. Although the Romans could have exploited the whole thickness of some outcrops (now disappeared) of these carbonatic lithotypes at the deepest part of the valleys, we have constrained a local provenance of the breccias so commonly used in the monumental works of the Flaminia.     

Characterisation and provenance of stones used in the mosaics of the domus dei Coiedii at Roman Suasa (Ancona,Italy)

The mosaics covering the floors of the rooms of the domus dei Coiedii at Suasa (Ancona, Italy) may be dated archaeologically and artistically between the late republican-Augustan age (end of the first century B.C.-beginning of first century A.D.) and the second century A.D.-first half of third century A.D. The floors were made mostly in opus tessellatum, only one in opus sectile. Tesserae used in opus tessellatum are made mainly of local stones, belonging to the so-called Umbro-Marchigiana Sedimentary Sequence: the white to pinkish and reddish tesserae consist prevalently of limestones belonging to the ‘Scaglia Rosata’ Formation (Late Turonian-Middle Eocene), and subordinately to the ‘Calcare Massiccio del Burano’, which is part of the ‘Calcare Massiccio s.l.’ Formation (Late Triassic-Early Lias). Most dark to black tesserae are composed of not fossiliferous marls and marly clays, which probably derive from the local ‘Marne a Fucoidi’ Formation; a number of them are made of very fine grained sandstones, which are found as pebbles in the alluvial sediments of the Cesano river close to Suasa, and, some, of aphyric leucite-bearing basanites from the potassic Quaternary magmatic province of central-southern Italy. Artificial glasses (red and green, rich in Pb and low in Sb; light blue, low in Pb and high in Sb), containing microliths of Pb-rich phase(s) and of wollastonite, were also used in some floors. The stones used in opus sectile are (1) sedimentary: nodular limestones belonging to the ‘Rosso Ammonitico’, which occurs in the Umbro-Marchigiana Sedimentary Succession; black marls and marly clays similar to those used in opus tessellatum; onyx marble; (2) magmatic: porphyrites (‘porfido verde antico’) and gabbros (ophite); (3) marbles: different kinds of coloured marbles, comprising ‘marmo cipollino’, ‘rosso antico’, ‘pavonazzetto’, ‘portasanta’, ‘giallo antico’, ‘bigio antico’, ‘brecce coralline’. White marbles from Marmara and Carrara were also employed.     

Archaeomagnetic investigation of a metallurgical furnace in Pisa (Italy)

An archaeological excavation has been carried out at Pisa (Italy), unearthing an ancient metallurgical workshop. Since archaeological burnt materials provide important records of direction and intensity of the Earth's magnetic field in the past and they can be used to better improve geomagnetic secular variation curves (SVCs), an archaeomagnetic study has been performed. This small copper-alloy furnace presents a circular concave shape covered with a thin layer of mortar, with some traces of heated clay surrounding the feature that confirms the high temperature reached inside it. Archaeological context dating points to the last firing of the furnace between the last quarter of the 13th century and the first quarter of 14th century AD, when then the metallurgical workshop was transformed in a warehouse. Archaeomagnetic sampling has been performed using the modified Thellier method, by collecting several, large and independently oriented aliquots of heated clay, forming the bottom part of the circular wall of the structure. Laboratory treatments have been conducted at the IGG-CNR ARCHEO_LAB (Pisa, Italy) and at St. Maur Palaeomagnetic laboratory (Paris, France). Analytical measurements of the thermo-remanent magnetization index acquired from the samples have been performed using a large cell induction magnetometer for large samples, and the characteristic remanent magnetization (ChRM) has been successfully isolated after an alternate field demagnetization cleaning procedure for each sample. The final mean archaeomagnetic direction has been calculated at sampling site (D = 6.9°; I = 52.8°; N = 9; k = 305; α₉₅ = 2.6°) following the Fisher Statistics, and it exhibits a perfect agreement with some coeval already published directions obtained from Mt. Arso lava flows, these latter being an important anchor point in the preliminary Italian secular variation curve. Comparison with the preliminary Italian SVC, the French SVC and the SCHA.DIF.3K archaeomagnetic regional model have permitted to define an archaeomagnetic absolute age confirming the conventional archaeological age, underlining the importance of this result into the Italian archaeomagnetic data set.     

The wood of “C” and “F” Roman ships found in the ancient harbour of Pisa (Tuscany, Italy): the utilisation of different timbers and the probable geographical area which supplied them

During the excavation of the Etruscan and Roman harbour of Pisa, several shipwrecks were found. The wooden timbers constituting the ship C and ship F (which date back to the first and the second century A.D., respectively, as attested by archaeological findings) were selected in order to collect information about the technological knowledge of the time. Pinus pinaster Aiton was essentially utilised for the planking of ship C and Quercus sp. caducifolia for that of ship F. The choice of timber for the other parts of ship C hull was much more differentiated. Ship C seems to be built in a careful way and its characteristics when added to its overall lightness, seem to reflect its use as a higher capacity boat built for sea sailing. Ship F seems more linked to short voyages in inner fresh waters. The utilisation of different woods was linked not only to the technological characteristics of wood, but also to their easy availability. Palynological analysis, carried out on the clay sediments embedding the shipwrecks, has shown that the flora of Pisa area in that time period would have allowed the acquisition of all the timber species used for both the ships’ construction, with the exception of the fig wood. However, a foreign origin of the timber from somewhere else in the Northern Mediterranean area has not been excluded.     

Roman bricks from the Lagoon of Venice: a chemical characterization with methods of multivariate analysis

From 18 archaeological sites of the Lagoon of Venice 75 bricks belonging to Roman and medieval building levels have been analysed. Chemical composition and geometric measures allow the characterization of a group of 24 Roman bricks of Imperial age. The group formed by means of fuzzy c-means cluster analysis applied on chemical data have been tested by principal component analysis and finally subjected to discriminant analysis to estimate the relative weights of original variables and classify new elements. Correlations among the data of the major chemical elements confirm the reliability of the complex of chemical data. The aim of this research was to obtain a chemical characterization of Roman bricks (and later, of the medieval ones) coming from the lagoon of Venice thus making it possible: 1) to recognize the age of a brick by means of its chemical analysis; 2) to date the layers of archaeological excavations or the ground where there are medieval building foundations by means of membership bricks; 3) to calculate the rate of local ground lowering in the elapsed years by the difference in level from one layer to another; 4) to estimate local rates of land subsidence by comparison with mean values already known.     

Biofouling of crypts of historical and architectural interest at La Plata Cemetery (Argentina)

Cemeteries are part of the cultural heritage of urban communities, containing funerary crypts and monuments of historical and architectural interest. Efforts aimed at the conservation of these structures must target not only the abiotic stresses that cause their destruction, such as light and humidity, but also biofouling by biotic agents. The purpose of this study was to assess the development of biofouling of several historically and architecturally valuable crypts at La Plata Cemetery (Argentina). Samples obtained from the biofilms, lichens, and fungal colonies that had developed on the marble surfaces and cement mortar of these crypts were analyzed by conventional microbiological techniques and by scanning electron microscopy. The lichens were identified as Caloplaca austrocitrina, Lecanora albescens, Xanthoparmelia farinosa and Xanthoria candelaria, the fungi as Aspergillus sp., Penicillium sp., Fusarium sp., Candida sp. and Rhodotorula sp., and the bacteria as Bacillus sp. and Pseudomonas sp. The mechanisms by which these microorganisms cause the aesthetic and biochemical deterioration of the crypts are discussed.     

Tree roots and damages in the Jewish catacombs of Villa Torlonia (Roma)

Damages to hypogeal archaeological monuments, caused by the growth of tree roots, are frequently reported in the city of Rome. Problems of compatibility between trees and underground structures may become complex in the case of historical gardens. The Jewish catacombs of Villa Torlonia show relevant conservation problems, some of them arising from damages due to root growth, and consolidating interventions seem to be urgent. Some species in the gardens, especially Ficus carica L., but also Quercus ilex L. and Pinus pinea L., have developed a strong root system, growing for many meters in lateral distance and for some meters vertically. The plants responsible for the various alterations were identified by their wood anatomy and a methodology to treat similar problems has been proposed. Data collected aim to avoid errors made in managing the plant cover of an archaeological site.     

Detection of diagenetic alterations by Spectroscopic Analysis on Archaeological Bones from the Necropolis of Poseidonia (Paestum): A case study

Understanding the chemical and physical alteration in archaeological bones, occurred after burial, is very interesting for researchers. In this paper, we present a study on the diagenetic alteration of human archaeological bony tissues from Paestum (South Italy), by combining complementary spectroscopic techniques, such as solid-state nuclear magnetic resonance (NMR), infrared spectroscopy (IR), and X-ray diffraction. In particular, ¹³C nuclear magnetic resonance–cross polarization-magic angle spinning (¹³C NMR CP-MAS) spectroscopy allows to identify and discriminate the adsorbed calcite, that is a diagenetic contaminant, from the structural one of apatite and ¹H NMR-MAS spectroscopy shows how the degradation of organic phase of collagen is related to the time. The NMR data are combined with crystalline index, measured by X-ray diffraction, and with the splitting factor obtained by infrared spectroscopy. Moreover, the evaluation of the relative content of biogenic structural carbonate and of diagenetic fluorine is reported.     

Pore structure of historic and repair Roman cement mortars to establish their compatibility

Mercury porosimetry was applied to the study of pore structure of the historic Roman cement mortars representative of different locations in Europe and time periods as well as different application techniques from architectural castings to in situ formed renders and profiles. Three categories of pores were found to coexist in the mortars. The finest pores, with diameters below 0.1 μm, are present within the hardened aged Roman cement matrix. The larger ‘air’ pores, with diameters between 0.2–2 μm, are due to the evaporation of the excess unbound water and restricted hydration. Pores larger than 2 μm are rare and, in general, can be related to microcracking induced by shrinkage drying and mortar weathering. The mortars have rarely been found to develop a dense fine-porous microstructure characteristic of the ideal conditions of moist-curing; massive architectural castings being the only exception identified. The presence of larger ‘air’ pores was, in turn, almost universally observed. The investigations of the freshly prepared Roman cement mortars have revealed that the restricted hydration could be due to the exposure of the freshly laid surface to dry real-world external environments, a high water-to-cement ratio in the original mortars, or the drawing of water from the stucco mass due to insufficient pre-wetting of the porous masonry. The insufficient reactivity of historic cements, resulting from a high content of over-burned, non-reactive cement components or coarseness of the cement grains, could be another reason for yielding poorly hydrated mortars in the past. In general, Roman cement stuccoes are in an excellent state of preservation in spite of their usual exposure to polluted urban environments for more than a century. Therefore, the coexistence of Roman cement mortars of widely different pore structures has not brought about any problems of incompatibility which field observations could reveal. The Roman cement repair materials have been found to develop pore structures similar to those of historic mortars. Therefore, they are in broad terms compatible with historic masonry or stuccoes. However, the porosity and strength of the repair materials can be controlled by a careful manipulation of the water-to-cement ratio of the mix to adapt them better to the properties of the host material.     

PIXE analysis of V–XVI century glasses from the archaeological site of San Martino di Ovaro (Italy)

The analysis of 42 glass fragments, excavated in the Italian archaeological site of San Martino di Ovaro, that includes a palaeochristian church dated from the V–VI century, has been done using the PIXE technique in a fully non-destructive way without any sample preparation. The results have been validated with a set of standards and using PIGE data acquired in parallel. The data of 29 of the 42 glasses indicate that an earlier group of samples (window sheets and sacred vessels, dated from the V–VI century) is typical of the Roman technology and can be associated to a Levantine production of natron glass. The blue glasses of this group are all window sheets coloured with cobalt, probably from the Near-East. The remaining heterogeneous samples (lamps, necklaces, cups) are related by their type and function and by the different compositions, to the later use of the site as a market place. The natron glasses of San Martino di Ovaro provide new data for the understanding of the changes in the glass industry in North-eastern Italy and nearby regions across the fall of the Western Roman Empire.     

A multi analytical approach to discriminate the Italian colored marble “Portasanta” from Portasanta “Marmor Chium” (Greece)

The “marble” Portasanta from Caldana (Grosseto, Italy) takes its name from the strict resemblance to the ancient Marmor Chium (also this called Portasanta) coming from the island of Chios in Greece. In this work, a complete characterization of the Italian Portasanta was made: chemical (X-ray fluorescence and isotopic analyses), mineralogical (X-ray diffraction on the bulk sample and on insoluble residue after acid attack), physical (water accessible porosity and imbibition coefficients), petrographical (optical microscopy) and mechanical (compressive strength test) analyses have been carried out in order to obtain a better distinction between Italian and Greek “marble”, sometimes mistaken. The Portasanta from Caldana (Italy) was quarried surely in the sixteenth century, but a possible use of this material during Roman time is still in doubt. The study of samples from some Tuscan archaeological sites (Torraccia di Chiusi, Siena and Roselle, Grosseto) allows us to confirm the use of Portasanta from Chios for the Torraccia site and that of Caldana for Roselle.     

Characterisation of wall paintings in the Sos Furrighesos necropolis (Anela,Italy)

The Sos Furrighesos necropolis (Anela) is considered to be one of the most important funerary monuments in Sardinia. The hypogeum consists of various graves, called Domus de Janas, which are decorated with Neolithic mural paintings and sculptures. This work was undertaken in order to clarify which techniques were used in the past, through the identification of pigments and binding media. The samples, scraped off from the paint surface, were studied by using various analytical techniques in order to characterise both the pigments and the binding media. The main problems concerning the characterisation were due to the small sizes (1–5 mg) of the samples and their complex nature. As regards pigments, X-ray diffraction and scanning electron microscopy-energy dispersive X-ray spectrometry analyses were performed on the samples. These techniques are well suited to the characterisation of inorganic pigments and have led to the identification of the red pigment as haematite. In order to characterise the organic binders, the samples were analysed by a procedure based on a gas chromatography–mass spectrometry technique, which allows proteinaceous and lipidic media determination in the same sample. In most of the samples, the presence of egg was suggested.     

Non-invasive spectroscopic measurements on the Il ritratto della figliastra by Giovanni Fattori: identification of pigments and colourimetric analysis

The painting Il ritratto della figliastra (Portrait of the Stepdaughter) by Giovanni Fattori (1889, Gallery of Modern Art, Pitti Palace, Florence) was investigated using non-invasive fibre optics reflectance spectroscopy (FORS). The use of compact and transportable instrumentation made it possible to easily record spectra of the polychrome surface at the restorer’s atelier during the restoration work. The results of colour analysis before and after the cleaning procedure of the painting are reported and discussed, together with an attempt at pigment identification.     

The funerary klinai of tomb 1 from Amphipolis and a sarcophagus from ancient Tragilos, eastern Macedonia: a physico-chemical investigation on the painting materials

Optical and SEM-EDS microscopy, X-ray powder diffraction and micro FT-IR spectroscopy investigations of the funerary klinai (couches) of Tomb 1 from Amphipolis and a stone sarcophagus from ancient Tragilos—two painted monuments made by Macedonian craftsmen of the Early Hellenistic period—identified the original materials and painting technique, as well as synthetic materials used as consolidants during past restoration treatments. The original organic binders and the superficial modern coatings have been identified by micro FT-IR spectroscopy applied directly to the sampled powders or tiny fragments and to their solvent—soluble fractions. The pigments identified on the couch of Amphipolis are: red and yellow ochre, cinnabar, Madder lake, paratacamite and antlerite, carbon black, calcium carbonate, kaolin and gypsum. The identification of egg and animal glue confirms the application of tempera and secco techniques. The detection of polymers such as polydimethylsiloxane, polyvinyl acetate and alkyd resins, is related to modern restoration products. The pigments attested on the paintings of the Tragilos' sarcophagus are: red and yellow ochre, Egyptian blue, malachite, carbon black, calcium carbonate and gypsum. The absence of organic binders combined with the constant presence of calcium carbonate in all the examined samples suggests the use of lime as the binding medium in the painted decoration of the sarcophagus. The presence of Paraloid B72 is related to recent conservation treatments.