Pentelic Marble Research Articles

Roman White Marbles in Northern Marche Region (Italy): An Archaeometric Provenance Study

Archaeometric investigations were conducted on Roman marble statues, engraved slabs, and memorial bases discovered in various archaeological sites located in the present Marche Region (Italy), including Fanum Fortunae, Pisaurum, and Potentia. These artefacts are currently housed in the Archaeologic Museum of Fano, the Archaeologic Museum of Pesaro, and the Archaeologic Museum of Porto Recanati (Macerata). Spanning from the Republican age to the Severan dynasty and up until the middle of the fourth century AD, these archaeological artefacts attest to the existence of numerous urbanized Roman colonies adorned with monuments and marble decorations. Mineralogical and petrographic examinations, along with C-O stable isotopic and chemical analyses (MgO and Sr), were carried out to both characterize the marble features and determine their provenance. This research aimed to delineate the specific use and distribution of these marbles across different chronological periods. The results indicated that Proconnesian marble was mainly used in the engraved slabs from Fanum Fortunae, with one exception in which Pentelic marble was identified. The sculptures from Fanum Fortunae and Potentia were carved from white marbles, including Lunense and Parian marbles (Parian-1 and Parian-2 types), with limited use of Pentelic and Thasian marbles, notably the Thasian-3 variety. Memorial bases from Pisaurum were identified to be made from Parian, Proconnesian, and Thasianmarbles. The archaeometric provenance of the different marbles was correlated with the archaeological dating of the artefacts to establish a chronological framework describing their use over time. This work provides an opportunity to appreciate Roman artifacts crafted from precious white marbles, which are housed in various museums throughout the Marche Region. The archaeometric investigation offers a significant contribution to the dissemination of knowledge and serves as a valuable tool for the enhancement of this archaeological and cultural heritage, potentially informing policies aimed at promoting geotourism.

A marble Sarcophagus of Gadara (Umm Qais), Jordan: insights on its provenance

This research investigates the archaeometric characteristics of the marble sarcophagus displayed in the Umm Qeis Museum of Antiquities, Gadara (Umm Qais), north Jordan. Marble sarcophagi are very rarely found at archaeological sites in Jordan; the Gadara marble sarcophagus is, therefore, unique. This sarcophagus, dated to the 3rd century AD, presents only the base and the lid; the lid shows remnants and traces of the chiton and himation of two effigies, while the pedestal shows remnants of a foot and a weapon, both probably indicate an Attic sarcophagus. The research undertaken aims to determine the quarry origins of the box and the lid, while also considering the notion of some scholars that the boxes of Attic sarcophagi were carved of Pentelic marble, while the lids were carved of Hymettian marble. The results of the mineralogical, petrographic, chemical and isotopic analyses showed that the most likely quarry origin of the two marble parts is Pentelikon Mountain, Athens, Greece. The sarcophagus’s high quality, elaborate decorations, large volume and heavy weight, along with the inland location of Gadara, suggest that it was ordered by a wealthy and/or a high-status Gadarene citizen.

The Protection of Building Materials of Historical Monuments with Nanoparticle Suspensions

Marble and limestone have been extensively used as building materials in historical monuments. Environmental, physical, chemical and biological factors contribute to stone deterioration. The rehabilitation of stone damage and the delay of further deterioration is of utmost importance. Inorganic nanoparticles having chemical and crystallographic affinity with building materials is very important for the formation of protective coatings or overlayers. In the present work, we have tested the possibility of treating calcitic materials with suspensions of amorphous calcium carbonate (am-CaCO3, ACC) and amorphous silica (AmSiO2). Pentelic marble (PM) was selected as the test material to validate the efficiency of the nanoparticle suspension treatment towards dissolution in undersaturated solutions and slightly acidic pH (6.50). Suspensions of ACC and AnSiO2 nanoparticles were prepared by spontaneous precipitation from supersaturated solutions and by tetraethyl orthosilicate (TEOS) hydrolysis, respectively. The suspensions were quite stable (nine days for ACC and months for AmSiO2). ACC and Am SiO2 particles were deposited on the surface of powdered PM. The rates of dissolution of PM were measured in solutions undersaturated with respect to calcite at a constant pH of 6.50. For specimens treated with ACC and AmSiO2 suspensions, the measured dissolution rates were significantly lower. The extent of the rate of dissolution reduction was higher for AmSiO2 particles on PM. Moreover, application of the nanoparticles on the substrate during their precipitation was most efficient method.

Provenance investigation of Roman marble sarcophagi from Nicopolis, Epirus, Greece: revealing a strong artistic and trade connection with Athens

A large number of marble sarcophagi have been discovered in the extensive cemeteries of ancient Nicopolis, ranging in date from the Hadrianic period to the middle of the third c. AD. The archaeological study, based on typological and stylistic criteria, indicates that many sarcophagi are imported from Athens, while a large part seems to be the product of local workshops that often follows closely Attic models. In order to identify securely the marble used for the sarcophagi, and therefore the sources used by the local workshops, 14 representative sarcophagi from the Archaeological Museum of Nicopolis were sampled and subjected to full scientific provenance analysis. This involved a combination of (a) in situ examination of the whole objects using optical techniques for measuring grain sizes and translucency, and recording of inclusions, veins and other features; (b) stable isotope analysis; and (c) electron paramagnetic resonance spectroscopy. The results revealed a clear preference in the Pentelic marble: 12 out of 14 sarcophagi made in that marble, while 1 sarcophagus was made of marble from Thasos and 1 of an unidentified grey, coarse-grained, dolomitic marble. Pentelic marble was identified in sarcophagi considered as imports from Attica—as expected, but also in local products following attic models, with or without incorporating motifs from other places. This wide use of Pentelic marble for the local production, as well as the importation of Attic finished products, both luxurious options, designates the overall economic prosperity of Roman Nicopolis, but also its close trade and artistic connections with Athens.

Toward a virtual reconstruction of an antique three-dimensional marble puzzle

The reconstruction of broken objects is an important field of research for many applications, such as art restoration, surgery, forensics, and solving puzzles. In archaeology, the reconstruction of broken artifacts is a very time-consuming task due to the handling of fractured objects, which are generally fragile. However, it can now be supported by three-dimensional (3-D) data acquisition devices and computer processing. Those techniques are very useful in this domain because they allow the remote handling of very accurate models of fragile parts, they permit the extensive testing of reconstruction solutions, and they provide access to the parts for the entire research community. An interesting problem has recently been proposed by archaeologists in the form of a huge puzzle composed of a thousand fragments of Pentelic marble of different sizes found in Autun (France), and all attempts to reconstruct the puzzle during the last two centuries have failed. Archaeologists are sure that some fragments are missing and that some of the ones we have come from different slabs. We propose an inexpensive transportable system for 3-D acquisition setup and a 3-D reconstruction method that is applied to this Roman inscription but is also relevant to other applications.

Optical transmission properties of Pentelic and Paros marble.

Ancient Greek and Roman sources report that the statue of Zeus in Olympia had a head, and in particular eyes, similar to the description of Zeus by Homer, so we think that the statue was visible to the human eye. Since the temple was 12m high, and had a small door and no windows, the illumination of the statue by conventional media is questionable. The aim of this paper is to characterize the optical transmission of Paros and Pentelic marble to demonstrate that it was possible to have the Zeus temple illuminated through the roof marble tiles. Spectral absolute transmittance measurements were taken in samples with different thicknesses using a calibrated spectrophotometer, as well as total transmittance measurements using a luxmeter. The results show that both types of marble transmit light and that Pentelic marble has a higher transmittance in the visible range than Paros marble in some cases and hence could have been one reason, among others, to change the type of marble in the roof in antiquity.

Influence of nitrogen dioxide and acetylene on marbles, ceramics and pigment

The air pollution has a great impact on the social and economic aspects all over the world. Thus, the interaction of materials with the atmosphere has received increased attention nowadays. In order to estimate the impacts of air pollution on the solid surfaces a suitable scientific basis is developed and the well known Reversed Flow - Inverse Gas Chromatography, RF- IGC, is used. This dynamic experimental technique leads to very interesting experimental results through the determination of some important physicochemical quantities. The solids studied were Pentelic marble, white TiO2 pigment, ceramic and the gases were NO2 and C2H2. The synergistic effects between acetylene and nitrogen dioxide were also investigated. Through the curves obtained for each adsorption quantity determined versus time, one can easily and accurately conclude the result of the pollution impact on every solid mentioned above. The surface topography and the mechanism of deterioration can also be studied. All the above answer in detail to the questions of where, when and how the influence of gas pollutants on materials of cultural heritage takes place.

ON THE WHITE AND COLOURED MARBLES OF THE ROMAN TOWN OF CUICUL (DJEMILA, ALGERIA)

This paper reports the results of an archaeometric study of the local and imported marbles found in the Roman town of Cuicul (now Djemila, Algeria), a research project funded by the Sixth Framework Programme of the European Union. Of the few imported coloured lithotypes that have been found, four are of Greek origin and one was imported from Asia Minor. In addition, two other classical Roman coloured stones found on the site are probably of local North African origin (most likely one from Numidia and one from Algeria). With regard to the grey and white marbles employed in the statuary and architecture, petrographic study in thin section and the δ13C and δ18O isotopic data emphasize the frequent use of the local fine‐grained lithotype from Filfila (Skikda) together with imported Greek lithotypes (i.e., Pentelic marble, the dolomitic variety of Thasian marble, and Parian marble from Lakkoi) as well as different varieties of the so‐called ‘greco scritto’, whose provenance in some cases still remains uncertain. In fact, the petrographic and geochemical features of the marbles do not always match those known for the classical ‘greco scritto’ from the quarry of Cap de Garde, near Annaba (Algeria).

Pentelic marble in architecture at Rome and the Republican marble trade

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NDT&E techniques and SEM‐EDS for the assessment of cleaning interventions on Pentelic marble surfaces

AbstractIn this work, several non‐destructive testing and evaluation (NDT&E) techniques along with scanning electron microscopy with energy dispersive x‐ray spectroscopy (SEM‐EDS) were applied on Pentelic marble surfaces. The investigated Pentelic marble surface disclosed a representative decay pattern that usually develops in polluted urban atmosphere such as the Athens centre. The applied techniques aimed to collate as much as possible evidence about the physico‐chemical and aesthetical characteristics of the examined surfaces before and after the pilot cleaning treatments, in an attempt to configure an effective assessment methodology of cleaning interventions. The applied NDT&E techniques were fibre‐optic microscopy, colourimetry and laser profilometry. The results were encouraging enough to propose the use of these NDT&E techniques along with SEM‐EDS as an everyday assessment tool of cleaning conservation interventions on Pentelic marble. Copyright © 2008 John Wiley & Sons, Ltd.

Surface Consolidation of Pentelic Marble: Criteria for the selection of methods and materials - The Acropolis case (6 pp)

GOAL AND SCOPE: In order to realize surface consolidation of Pentelic marble on the Acropolis monuments, we have collected the criteria that have to be fulfilled by the methods and materials without side effects on the marbles (and other stones). When the existing methods and materials did not satisfy the requirements (criteria), we invented new ones. The criteria were collected from the literature, by thermodynamic and kinetic viewpoints, by laboratory experiments and in situ observations on monuments, both in Greece and in several countries in which the various methods and materials were applied. Concerning our method of 'Inversion of sulfation', performed by spraying a K2CO3 solution, its concentration and its temperature were controlled in order to have a total inversion (certified by liquid crystals) of gypsum back to CaCO3. For the new material of ours, 'Reinforced Lime', in order to eliminate the disadvantages of plain lime (low carbonation rate, low mechanical properties of CaCO3 formed, lack of carbonation in the bulk of lime), measurements of the rate of carbonation were performed in plain lime and in lime with a different CaCO3 concentration beforehand as well as in a different CO2 environments, using DTG and XRD to measure the rate of carbonation. The detachment (kg/cm2) of marble specimens stuck by lime in each case was also measured. A microscope was also used to measure the dimensions of the grain in each case as well as ammonium citrate and thymolphthalein to certify the depth of carbonation in each case. Part of the work was communicated in an international congress. A table with the criteria of the selection of the methods and materials for the consolidation of Pentelic marble surfaces (and other stones) was established. None of the employed methods and materials fulfilled the criteria. Only the 'Inversion of gypsum' and the 'Reinforced Lime' were adopted and applied to the Acropolis monuments and to other monuments in Greece and in several other countries. All criteria must be used for the selection of methods and materials for the consolidation of the monument surfaces. This is why we have already studied with the same procedures, methods and materials for restoration, surface cleaning and protection.

Surface roughness evaluation of marble by 3D laser profilometry and pulsed thermography

Three dimensional (3D) laser profilometry (LP) and pulsed thermography (PT) were used in the inspection of Pentelic marble. Quarry Pentelic marble samples, after processed with different roughness treatments (i.e. 60, 80, 100, 220, 400 and 600 mesh), were evaluated in the laboratory. Furthermore, different surface cleaning treatments were applied to a Pentelic marble surface in situ and then representative samples were collected and evaluated in the laboratory by the means of these two non-destructive techniques. Quantitative analysis of all samples was performed. The surface roughness parameter Rq at a specific length scale was estimated by the use of the LP scanning approach. Furthermore, 3D micro-topography plots from the laser scans were attained. PT, through the formation of temperature—time plots that display the intensity of pixels as a function of time on the obtained thermal images, was able to distinguish the influence of the applied roughness treatments. Results indicate that these two non-contact and non-destructive techniques can be used for the assessment of surface roughness.

Kinetics of dissolution of powdered Pentelic marble in undersaturated solutions: the role of particle characteristics

In the present study, the effect of mesopore and particle size distributions on the kinetics of dissolution of powdered Pentelic marble was investigated. Powders obtained by grinding marble slabs in an agate mortar with a pestle (1–3.5 min) were found to be nonporous by nitrogen absorption measurements. These powders, upon dissolution under conditions of constant undersaturation, 25 °C, pH 8.25, showed that the kinetics in the absence of mesopores depended on the number of active sites on the exposed surface. Thus, powders consisting of smaller particles, having higher specific surface areas, yielded higher rates of dissolution. Powders, however, which were prepared by grinding marble slabs in a cylinder mill for time periods between 2.0 and 30.0 min, and which exhibited considerable mesoporosity, showed the opposite trend. The rates of dissolution measured for these powders in undersaturated solutions increased with increasing mean particle size and decreased with increasing specific surface area. This finding suggested that the presence of mesopores resulted in lower dissolution rates even though the exposed total surface area was larger. Furthermore, the larger the number of mesopores in a powder sample the slower the corresponding dissolution rates in undersaturated solutions.

Short free running Nd:YAG laser to clean different encrustations on Pentelic marble: procedure and evaluation of the effects

On ancient Greek monuments of Pentelic marble, environmentally induced encrustation (black dendritic and thin) along with layers with ancient treatments (patina) were irradiated with a Nd:YAG laser system operating at the fundamental mode ( λ = 1064 nm) with t d = 20 μs (short free running Nd:YAG laser). Laser experiments were coupled with the spraying of small quantities of distilled water on the encrustation before the irradiation. The effects of the laser-assisted cleaning were investigated using thin section analysis, optical microscopy, scanning electron microscopy coupled to energy dispersive X-ray analysis, infrared spectroscopic analysis, and X-ray diffraction analysis, as well as color measurements and imaging analysis using multi-spectral imaging. Based on the results, the main evaluation criteria were achieved for the application of the short free running Nd:YAG laser system for cleaning purposes. Multi-spectral imaging enables the evaluation of color and textural changes and, therefore, can be considered as an appropriate tool for the in situ monitoring of the cleaning process.

Variability of Dissolution Rates at Constant Undersaturation

Dissolution processes play an important role in marble weathering. Investigation of the dissolution kinetics of powdered Pentelic marble, a calcitic natural stone, showed that the rates measured at constant undersaturation decreased with time. It was found that the rate of dissolution decreased sharply to about 50% of the initial value before 5% of the initially suspended powder was dissolved. Past a dissolution extent corresponding to 25% with respect to the suspended solid, the rates of dissolution at the same constant undersaturation reached a stable value corresponding to 20–25% of the initial rate measured. The reduction in the rates of dissolution up to 25% of mass loss was in agreement with the reduction in the total surface area exposed to the solution, suggesting a dependence of the rate on the number of active sites on the surface of the dissolving material. The decrease in the dissolution rates did not depend on the undersaturation of the solution or on the physical characteristics of the particles such as specific surface area, porosity, and particle size distribution. Equal mass losses, with respect to the initially suspended solid, of different samples exhibited the same relative decrease in rate regardless of the conditions of the aqueous solutions.

Evaluation of cleaning procedures on the facades of the Bank of Greece historical building in the center of Athens

The facades of the Bank of Greece historic building, mainly consisted of porous stone, gray marble and white pentelic marble, are subjected to an intensive air pollution attack in the center of Athens. A diagnostic study was carried out prior to the cleaning procedures for the weathering evaluation. Weathering appears mainly as black depositions, salt crusts, and oily depositions, due to the heavily polluted urban atmosphere from the nearby traffic. Previous improper cleaning treatment by water spray under high pressure caused detachment of grains and fissuring which were recognized as mechanical abrasion of the surfaces. In this study, a pilot investigation is performed with the intention of evaluating the most appropriate cleaning treatment. Therefore, several cleaning procedures were performed in the laboratory and in situ for the evaluation of methods and products applied on the facades. Both chemical and physical cleaning procedures were applied and they were chosen for their selective action: only water and sepiolite for solvent action, ammonium bicarbonate for exchange action, EDTA for the chemical chelating action and microblasting for physical action were used. In situ non-destructive evaluation was performed by Fiber Optics Microscopy in order to assess the counteractions of each cleaning method to the original surfaces. Digital Image Processing was also used to account for the efficiency of each cleaning method.

Dissolution Effects on Specific Surface Area, Particle Size, and Porosity of Pentelic Marble

Dissolution of natural stone such as marble is not limited to its surface. The porous structure, known to play an important role in stone decay, is also affected by the conditions of dissolution. In the present work, the changes in pore size distribution of Pentelic marble particles accompanying chemical dissolution in undersaturated solutions and at alkaline pH 8.25 were investigated. The specific surface area and the mesopore distribution of the Pentelic marble tested showed a pronounced decrease to very low values. On the other hand, the sizes of macropores exhibited a tendency to increase with the extent of dissolution due either to dissolution in the interior of the pores or to fusion of small pores into larger. Furthermore, the number of small particles decreased significantly, reaching complete disappearance, depending on the extent of dissolution. At the same time, the relative number of particles of intermediate size increased.

Compositional characterization of encrustation on marble with laser induced breakdown spectroscopy

This study deals with the analysis of encrustation on marble by laser induced breakdown spectroscopy (LIBS), with the aim to obtain quick in-situ information on the in-depth profiling of the encrustation before advancing to conservation treatments. The encrustation examined is formed on exposed marble: (a) as products of the interaction between the stone surface and atmospheric pollutants (dendritic black and thin black encrustation, of approximately 300 and 200 μm thicknesses, respectively); (b) from deposition of soil–dust on marble surfaces (soil–dust crust, 300 μm thick); and (c) from treatments conducted in the past for aesthetic and/or protective purposes (patina samples, 300 μm thick). The crusts examined are multilayer encrustations on un-weathered marble, as revealed by studying cross sections with optical microscopy and scanning electron microscopy coupled with energy dispersive X-ray analysis. The elemental LIBS profiles of black encrustation based on relative spectral line intensity values show that the Fe, Si, Al and Ti content relative to Ca content decrease significantly with depth, expressing, thus, contamination decreasing within the alteration layers, since these elements originate from atmospheric pollution and deposition. In the cases of soil–dust encrustation and patina samples Si I and Al I emissions identified throughout the analyzed crust, indicate deposition of soil–dust and remnants of previous treatments, respectively. Therefore, LIBS, a micro-destructive technique can be used as an autonomous in-situ diagnostic technique to obtain in-depth elemental profiling of encrustation even in cases of highly in-homogeneous layered crusts, such those of un-weathered Pentelic marble.

Dissolution of Pentelic Marble at Alkaline pH

The kinetics of dissolution of powdered Pentelic marble from two different sites located on Mount Pentelicon of Attica, Dionysos and Cave, were investigated. The results were compared with those of synthetically precipitated calcite, the main inorganic constituent (>98%) of the tested marbles. The dissolution process at solution undersaturation near equilibrium in all cases showed a linear dependence of the rates of dissolution on the relative solution undersaturation. The dissolution was found to be polynuclear, surface diffusion controlled. Morphological examination of the specimens showed that dissolution proceeds through formation of steps, cracks, pores, and layerwise disintegration, corroborating the conclusion from the kinetics results. Powdered marble is suggested to be an excellent model system for the investigation of marble dissolution as it exhibited remarkable similarities with the dissolution of whole marble blocks.

Sorel's cement mortars: Decay susceptibility and effect on Pentelic marble

To evaluate the decay susceptibility of mortars of magnesium oxychloride cement used for the restoration of blocks of Pentelic marble of the Athens Acropolis monuments, mineralogical and physicochemical analyses were performed on samples from different exposure conditions. The decay of mortars depends mainly on environmental influences. The observed decay forms and the responsible processes are: (1) expansion of mortars leading to break-up of the marble as a result of the carbonation of oxychloride phases; (2) disintegration of mortars exposed to washing and staining of marble due to the release of magnesium chloride; and (3) in mortars sheltered from rain action, efflorescence due to the sulfation of mortar constituents that yields hydrated sulfate salts of magnesium and calcium with different water molecules; their hydration, crystallization, and rehydration during microclimatic shifts imply volume changes and the release of corrosive solutions leading to formation of cracks and staining.