THE PROPERTIES AND IDENTIFICATION OF MARBLE FROM PROCONNESOS (MARMARA ISLAND,TURKEY): A NEW DATABASE INCLUDING ISOTOPIC,EPR AND PETROGRAPHIC DATA*

This paper reports an updated and enlarged archaeometric database of Proconnesos marbles with the aim of attaining more reliable inter‐ and intra‐site identification. Quarry and artefact samples (n = 397) from 23 different quarrying areas were characterized using petrographic, isotopic and EPR results. The most distinct property of Proconnesos marbles is their extremely weak EPR intensity, associated with the low concentration of Mn²⁺impurities. This feature, supported by the contribution of other important isotopic and petrographic variables, forms the basis for the correct identification of Proconnesos marbles. Within the site the distribution of properties is relatively homogeneous; only limited intra‐site discrimination is possible. All the experimental results, as well as the quarry samples are made available to other researchers willing to measure additional experimental properties, thus increasing the rate of within the site discrimination. Extensive survey has proved that, although about 10% of the samples exhibit maximum grain size below 1.0 mm, no locations exist where fine grained marbles could be intentionally quarried. The historical aspects of Proconnesos marble quarrying and usage are also discussed.     

The marbles of two early Christian churches at Latrun (Cyrenaica,Libya)

The provenance of twenty-seven architectural marbles from the two 6th century AD Christian churches of Latrun (Cyrenaica, Libya) has been established by discriminant function analysis of twelve isotopic, EPR and petrographic/morphological variables. Sixteen samples (59%) originate from Proconnesos, while 8 samples (30%) are assigned to the calcitic quarries of Thasos and 1 to the Docimium quarries near Afyon. The last two samples are of uncertain provenance and might be Proconnesian as well. These results demonstrate that the suggestion made long ago by Ward-Perkins that the presence on non-Proconnesian, possibly Thasian, marbles at Latrun was well founded. Particularly interesting is the strong correlation found between provenance and type of the architectural element sampled. Thasian marbles at Latrun were used exclusively for the manufacture of chancel screens. Seven out of nine screens sampled have this provenance, suggesting that the use of different materials is related to issues of work organisation and specialisation in different marble production centres.     

Determining the provenance of black limestone artifacts using petrography,isotopes and EPR techniques: the case of the monument of Bocco

This paper investigates the provenance of the black limestone of the monument known as Bocco, named after the king of Mauretania who presented Silla with this work as a sign of his submission to the power of Rome. A multi-method approach, comprising petrographic observations, carbon and oxygen isotope composition and electron paramagnetic resonance (EPR) spectra characteristics, was used for this purpose. The monument is part of a reconstruction of a rectangular base (approx. 8 × 2 m) which is likely to have served as the base for a bronze statuary group and is currently composed of six blocks of limestone whose exterior is engraved with a fine frieze. The results of the different analyses were compared with the data of a published database of the most important black limestone quarries exploited during Roman times in the Mediterranean area. The petrographic and physico-chemical parameters did not prove to be very effective in determining the provenance of the black limestone of Bocco; the isotopes result even raised some uncertainty as to whether all six blocks came from the same quarry, though this doubt was dispelled by the EPR data and, above all, by the evident petrographic similarity between them. Differences in the isotopic composition of the various blocks may be due to an in situ rock alteration process caused by interaction with an aqueous fluid. It was, however, impossible to determine with certainty the origin of the material of the stone artifact using the database available; it is possible that the black limestone of Bocco came from an ancient quarry that is likely to be located in north western Africa but has not yet been uncovered. An alternative hypothesis, according to which the limestone used for the monument of Bocco came from the ancient quarry of Ain el Ksir, one of the Tunisian quarries present in the database, is also discussed.     

A Multi‐Method Database of the Black and White Marbles of Göktepe (Aphrodisias), Including Isotopic,EPR, Trace and Petrographic Data

A database of the ancient marbles of Göktepe near Aphrodisias is reported, and includes 160 white, black and bichrome samples from 13 quarries and two waste deposits. The quarries are grouped into four districts. Districts 1 and 2, to the north, produced exclusively black or dark grey marbles (nero antico). Districts 3 and 4 produced white statuary marble. Nero antico and a black and white stone were also quarried in district 4, where the black marble surfaces again. The samples were characterized using petrography, isotopic analysis, EPR spectroscopy and trace analysis. The Göktepe white exhibits an unparalleled combination of fine grain, low EPR intensity and high strontium concentration that often allows easy identification. The isotopic values are less distinctive and similar to those for Carrara. In most cases, however, they are tightly grouped and also quite indicative. The black marbles exhibit a much weaker metamorphic overprint. With respect to the white marbles, they show analytical similarities but also notable differences. Therefore, establishing their provenance can be more difficult and may require the support of petrographic analysis. The results suggest that the Göktepe marbles were among the most prized and widespread statuary marbles used in Roman times, particularly from the early second century ad onwards.     

SEM,EPR and ToF-SIMS analyses applied to unravel the technology employed for pottery-making by pre-colonial Indian tribes from Pantanal,Brazil

The present work aims at elucidating the technology applied in the fabrication of ceramic objects by the ancient ceramists that inhabited the western border of Pantanal, Mato-Grosso do Sul, with the help of a multidisciplinary approach making use of chemical and physical methods of analysis. The potshards under study show the presence of different types of additives, as determined by scanning electron microscopy (SEM) and time of flight secondary ion mass spectrometry (ToF-SIMS). The dispersion of the additives within the ceramic matrix was also addressed by SEM, which shed light on the mounting technique used by the potters to assemble the ceramic vessels. Moreover, the tensile strength conferred to the pottery by the use of a specific type of additive was evaluated by applying a mechanical test. These results were correlated with the firing temperature of the potshards, determined by means of electron paramagnetic resonance (EPR).     

DETECTION OF ANCIENT MARBLE FORGERY: TECHNIQUES AND LIMITATIONS*

Since 1960, scientific results have replaced aesthetic judgements in marble authentication studies and the technology to perform analytical tests on micro‐samples has developed rapidly. However, no single method can be used to determine the authenticity of a piece of marble. A ‘detective‐like’ investigation is usually adopted by using optical microscopy, ultraviolet‐induced fluorescence, provenance determination techniques and mineralogical, chemical and morphological analyses of the patina. A newly proposed thermoluminescence methodology calculates the ‘burial age’ of recently excavated objects or distinguishes artefacts exposed to sunlight since antiquity from those exposed recently. The technique shows a lot of potential; however, much work remains to be done.     

Black limestones used in antiquity: the petrographic,isotopic and EPR database for provenance determination

We compiled a database of some of the most important black limestone quarries used in Roman times to be able to determine the provenance of ancient artifacts. For this purpose, we adopted a multimethod approach using the techniques commonly applied to study the provenance of white marbles: petrographic observations, carbon and oxygen isotope composition, electron paramagnetic resonance (EPR) spectra characteristics. Few black limestones were quarried and traded in ancient times; indeed, the importance of most of these quarries was restricted to the areas in which they were located. In this work, we selected a limited number of quarries that produced material believed to have been exported and used throughout the Mediterranean area; most of the quarries selected are found in northern Tunisia, i.e. the Roman proconsular Africa: Djebel Oust, Djebel Azeiz, Ain al Ksir and (presumably) Thala. The “Nero Chiota” limestone quarried on the Aegean island of Chios (Greece) was also included in the database.     

Characterization of Pigment and Binder in Badly Conserved Illuminations of a 15th‐Century Manuscript

In this work we report a pre‐restoration spectroscopic study by a multi‐technique approach on the green pigment and the binder used in illuminations in a codex of the late 15th century. Our analysis aimed to characterize the badly deteriorated parts of the codex, mainly the green parts, by electron paramagnetic resonance (EPR), X‐ray diffraction (XRD), X‐ray fluorescence (XRF) and infrared spectroscopy (ATR‐IR). We will show that a combined study by EPR and IR spectroscopies on model systems allowed us to refine the general information obtained with the other techniques and to identify the binding media surrounding the chromophore Cu(II) ion.     

The Asiatic marbles of the Hadrian's Villa at Tivoli

Multi-method provenance studies, including petrographic, isotopic, electron paramagnetic resonance and trace chemical analyses, have been carried out on 20 white, 9 black and 1 red artifacts purposely selected to investigate the use and distribution of sculptural marbles at the Hadrian's Villa. A large fraction of the marbles tested (21 samples, 70%) are shown to be from Asia Minor, mostly originating from the recently discovered site of Göktepe near Aphrodisias (15 or 71%). All the 9 black samples investigated and 6 out of 11 white Asiatic marbles are from Göktepe, the remaining being Docimium marble from Iscehisar (4 samples) and Aphrodisias marble from the city quarries (1 sample). The single red sculpture tested proved to be Carian red marble from the Iasos quarries, whereas non-Asiatic marbles include 3 Carrara and 6 Pentelicon samples. The selection of marbles tested is preliminary and incomplete, but, despite this, the results are noteworthy, especially since the marble of other sculptures from the Villa has already been identified as Göktepe. Together with other published results, the marble distribution at the Hadrian's Villa seems to suggest that the use of sculptural marbles in the Roman world underwent considerable changes around the turn of the 1st and the 2nd century AD. The evidence supporting this hypothesis is briefly summarized in the conclusions.     

COLOUR ATTRIBUTES OF MEDIEVAL WINDOW PANES: ELECTRON PARAMAGNETIC RESONANCE AND PROBE MICROANALYSES ON STAINED GLASS WINDOWS FROM PAVIA CARTHUSIAN MONASTERY*

Stained glass windows from the Carthusian Monastery of Pavia, dating back to the 15th century, were studied by combining two analytical techniques: electron probe micro‐analysis (EPMA) and electron paramagnetic resonance (EPR). Chemical compositions and oxidation states of the transition ions, present as minor elements, were investigated by EPMA and EPR, respectively, in order to ascertain the role played by chromophorous ions in the glass coloration. The investigated glass can be defined as K–Ca glass, and the panes with red, green and blue colours were produced using flashing techniques.