1,721,039 research outputs found
The ancient use of colouring on the marble statues of Hierapolis of Phrygia (Turkey). An integrated multi-analytical approach
No full textThe interest about the extent of the polychromy of ancient artefacts has increased in the last 10 years, increasing our knowledge on classical art, still often perceived as perfectly white. As a consequence, the development of methodologies allowing the detection and interpretation of the traces of colour remaining on the surfaces of archaeological artefacts has gained momentum.
This paper presents the results of a multi-disciplinary research carried out about the painting materials used in producing selected marble statues excavated from the archaeological site of Hierapolis of Phrygia (Turkey), integrating the art-historical approach and the archaeometric data. The artefacts discussed in this paper were excavated in the archaeological site of Hierapolis in the course of several years by the Italian archaeological mission (MAIER). The objects include the reliefs and decorative statuary of the Severan Theatre and the statues excavated from the North Agora of the archaeological site, which are currently preserved in the museum of Hierapolis-Pamukkale. The analytical protocol, based on non-invasive imaging techniques (ultraviolet fluorescence images—UVf and visible induced luminescence—VIL), was performed directly outdoor, in the archaeological site. Few microsamples were selected, collected and subjected to laboratory analyses (XRD, FT-IR, SEM-EDS and HPLC-DAD). The integrated protocol allowed for the identification of the colouring materials used in producing the polychromies under study
Società Italiana di Fisica - 100° Congresso Nazionale
No full textIn order to widen the data about roman polychromy, a sarcophagus belonging to first Christians burials sited in San Callisto complex in Rome was studied. Polychromy and materials were extensively investigated by using in-situ non-invasive techniques (multispectral photography, visible induced luminescence, X-ray fluorescence and fibre optics reflectance spectroscopy).
Furthermore small samples taken in secondary areas, with the aim of being less invasive as possible, were analysed in laboratory. Analytical methods include X-ray diffraction (XRD), FT-IR and isotopic analyses to understand polychromy and provenance of marbles
The ancient mortars of Serravalle fortification (Bosa, Italy): a case study
Full text linkThe case study is the pentagonal tower from Serravalle Castle fortification, located near to the river Temo (west-cost of Sardinia), above the medieval Bosa village (XII-XIV cent.). The castle belongs to the medieval Giudicato di Torres (X cent.) and then to Malaspina from Lunigiana (XII cent.), Turrritani, Arborea, Aragonese, until to the Catalans (from Alghero) that led it to decline (XVI cent.). The aim of this proposal is to analyze from mineralogical-petrographic point of view the mortars used in the construction of the tower. Samples were taken between the volcanic ashlars at different heights with respect to the ground level, to assess any compositional variations during the construction of the building. Through microscopic analysis, the compositional aspects concerning the nature and petro-mineralogical features of the raw materials used for the aggregate were defined. By image analysis (on meso-microscopic photographs) the vol.% of binder/aggregate ratios and their grain-size characteristics were determined and compared with the wt% data obtained from disaggregation method of mortars and acid attack of carbonate binder, in order to understand if the mixing ratios used by constructors have respected the production standards of those historic period. By X-ray diffraction (XRD) and termogravimetric/differential analysis (TGA-DSC) of enriched-binder samples, the presence of C-S-H phases and the hydraulic degree of mortars have been studied, to understand the possible use of pozzolanic material. Finally, to define the physical-mechanical properties of mortars were also determined: porosity, real and bulk density, PLT punching-index, theoretical values of compression and traction strengths
Portoro, the black and gold Italian “marble”
No full textPortoro is one of the most famous Italian black limestones due to its characteristic golden-yellow veins on a black background. It was used since Roman times, mainly in the city of Luni. Since the Middle Ages, its use is widespread in Genoa, and from the XVII century, it became one of the most common stones in religious buildings throughout Italy. At the end of the XIX century, its use has spread abroad, particularly in Europe and USA. It was extracted in several quarrying areas located near La Spezia, but at present, only five quarries are active. This stone, exposed to weathering, tends to bleach losing the appearance of its golden streaks that determine its aesthetic appeal. This research deals with the petrographic and chemical characterization of the Portoro macchia larga variety as well as the study of its chromatic alteration in order to define guidelines for the most suitable use of this stone and for restoration works
The short-term degradation of cellulosic pulp in lake water and peat soil: A multi-analytical study from the micro to the molecular level
No full textCellulosic pulp was analysed after two and five years of natural ageing in two different burial environments - lake water and peat soil - in order to investigate the chemical and structural changes undergone by the material. This research is part of a monitoring program developed in the archaeological site of Biskupin, whose final aim is to estimate the best re-burial conditions for an in situ conservation of archaeological wood. We applied SEM, FT-IR, XRD and Py-GC/MS with thermally assisted silylation using hexamethyldisilazane (HMDS) to obtain broad information on cellulosic pulp degradation.
SEM provided information on the structural changes undergone by the fibres and on the microbial activity. FT-IR highlighted a depletion of the carbohydrates in the most degraded samples. Py(HMDS)-GC/MS confirmed these observations and provided detailed molecular information on cellulose alteration. The crystallinity index (CI) of cellulose was estimated by XRD, showing that the degradation began in amorphous regions. The correlation between the CI and the relative abundance of anhydrosugars detected by Py(HMDS)-GC/MS demonstrated that pyrolytic reactions are also influenced by the degree of crystallinity of cellulose.
A mechanism of cellulose degradation in these natural environments was formulated: the degradation of cellulose in these natural environments proceeds through a depolymerisation step, initially involving the amorphous regions of cellulose, until the size of oligomers becomes sufficiently small to allow metabolisation by microorganisms or solubilisation by water. Secondly, a loss of carbohydrates was detected after five years of ageing and the loss reached 25% and 55% for the dark areas of samples aged in peat soil and lake water, respectively. Peat soil was found to be more suitable than lake water in terms of preservation of carbohydrates
Multianalytical approach to diagnosis and conservation of building materials: the case of Punta Troia Castle in Marettimo (Aegadian Islands—Sicily, Italy)
No full textThe paper presents the results of a multianalytical study carried out through laboratory investigations on building materials of “Punta Troia Castle” in Marettimo Island (Sicily). The main aims of the work were to characterize the petrographic nature and to determine the geological provenance of the stone materials used to build the castle as well as to define the causes and mechanisms at the origin of their decay, in order to support and ensure greater durability to the restoration interventions. Based on the collected data, the local dolomitic limestone may be stated as the main stone for reconstruction purposes. In fact, this building stone shows low porosity, high compactness and a very good durability with respect to any other lithotypes identified in the building structure of the castle. © 2016, Springer-Verlag Berlin Heidelberg
Ancient restorations at Hierapolis of Phrygia (Denizli, Turkey): Interdisciplinary research on materials and technologies
No full textThe restoration of architectural monuments constituted a common practice in the ancient Mediterranean world and the use of artificial binders in repairing blocks is attested both by literary sources and archaeological evidence. However, the knowledge on the use of these ancient binders and their components is limited, due to the shortness and indefiniteness of the ancient recipes and the difficulty of obtaining and analyzing samples from blocks that have remained exposed to atmospheric agents and have undergone degradation. The paper focuses on the exceptional context of Hierapolis of Phrygia (Denizli, Turkey), where many ancient binders used in the restoration of Roman Imperial-era buildings (Sanctuary of Apollo, Theatre, North Agora and Ploutonion) have been identified. Thanks to the good state of conservation of these materials, the paper offers the unique opportunity for studying the role of organic additives used in the ancient bonding mortars and understanding the technologies adopted in the architectural restoration. Several analytical methodologies (Pyrolosis and Gas chromatography coupled with Mass Spectroscopy; X-ray diffractometry and Optical Microscopy) were applied to identify the organic and inorganic components. The mortars sampled in Hierapolis showed the presence of casein, animal glue, beeswax and Pinaceae resin, in agreement with the survived ancient recipes on bonding mortars. However, the archaeometric data revealed the use of complex mixtures, which are also attested by the literary sources. In particular, the use of calcite together with various organic additives appeared to be a common practice. Criteria of selection and use of the different mixtures have been discussed
The production of terra sigillata in Arezzo, Central Italy: an archaeometric investigation
Full text linkThis work deals with the archaeometric investigation on 25 fragments of terra sigillata (red-coated ceramic ware and moulds) found in the city of Arezzo, Tuscany (central Italy), and attributed to several important workshops from the first century BCE to the second century CE. Optical and spectroscopic techniques were used to analyse both the ceramic bodies and the red slips. All the potsherds showed a very fine-grained ceramic body, sharing similar mineralogical composi- tions, mainly consisting in quartz, plagioclase, pyrox- ene, hematite, K-feldspars, and illite/muscovite. The mineralogical data suggest that both the red-coated wares and the moulds were produced using the same calcareous-illitic clay and fired under oxidising condi- tions at temperatures between 850°C and 1000°C. A K-rich illitic clay with a Fe content around 10–15% (in wt%) was used to elaborate the slips. Al-substituted hematite was found in red slips by micro-Raman spec- troscopy. Comparison of the chemical data with terra sigillata from other important production areas in Italy and from other regions of the Meditteranean Sea, allowed to define that the studied samples, locally pro- duced in Arezzo, differ systematically from all others, although they show similarities with nearby Pisan pro- ductions as well as those Puteolan
An EPR study of the marbles from quarries of the Denizli region (Turkey): A contribution to the provenance assessment of materials with close relationships
No full textThe analytical and spectroscopic discrimination of marbles coming from quarries used in historical times is a task object of a wide interest in archaeometric investigations. This task is even more difficult, when the goal of the provenance assessment is focused on marbles coming from historical quarries located in a close geographic area. In this paper, we present the results of a systematic Electron Paramagnetic Resonance spectroscopy study aimed at assessing the discrimination criteria among 5 quarries located in the Denizli region (Anatolia, Turkey) that were benefited in Hellenistic and Roman period to provide materials for the buildings in the nearby city of Hierapolis of Phrygia (Turkey). The resulting EPR characterisation is used, in combination with the results of isotope geochemistry and petrological observation, to define criteria able to discriminate the provenance of marble samples from the considered quarries. The criteria arose from the analysis operated through robust compositional statistical techniques over the results of the experimental investigation. In this approach, the internal structure of the multimethodic dataset was unravelled. The results here presented provide evidence of a good discriminating ability of the proposed approach
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