Deterioration of an Etruscan tomb by bacteria from the order Rhizobiales

7 páginas, 4 figuras, 29 referencias.The Etruscan civilisation originated in the Villanovan Iron Age in the ninth century BC and was absorbed by Rome in the first century BC. Etruscan tombs, many of which are subterranean, are one of the best representations of this culture. The principal importance of these tombs, however, lies in the wall paintings and in the tradition of rich burial, which was unique in the Mediterranean Basin, with the exception of Egypt. Relatively little information is available concerning the biodeterioration of Etruscan tombs, which is caused by a colonisation that covers the paintings with white, circular to irregular aggregates of bacteria or biofilms that tend to connect each other. Thus, these colonisations sometimes cover extensive surfaces. Here we show that the colonisation of paintings in Tomba del Colle is primarily due to bacteria of the order Rhizobiales (Alphaproteobacteria), which were likely influenced by the neighbouring rhizosphere community and the availability of nutrients from root exudates.This work was funded through the projects CGL2010-17183, 201030E011 and Consolider 2007-00058. M.D.H. was supported by a JAE Research Fellowship from CSIC, and S.C. was supported by a Juan de la Cierva contract.Peer reviewe

Recovery of archaeological wall paintings using novel multispectral imaging approaches

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SiO2 nanoparticles as new repairing treatments toward the Pietraforte sandstone in Florence renaissance buildings

In this work, the consolidation efficiency of SiO2 nanoparticles (synthesized in the Chemistry laboratories at the Tor Vergata University of Roma) was tested on Pietraforte sandstone surfaces belonging to the bell tower of San Lorenzo (Florence, Italy) and was fully investigated. Nanoparticles (synthesized in large-scale mass production) have been characterized by XRD—X-Ray Diffraction; Raman and FTIR—Fourier Transform Infrared spectroscopy; SEM—Scanning Electron Microscopy; while the Pietraforte sandstone morphology was examined by Porosimetry, capillary absorption test, surface hardness test, drilling resistance and tensile strength. The colorimetric measurements were also performed to characterize the optical modification exhibited by Pietraforte sandstones, especially after the SiO2 treatments. Our results show that applying to the Pietraforte, the new consolidating agent based on SiO2 nanoparticles, has several advantages, as they are more resistant to perforation, wear, and abrasion even long range (for long times of exposure and consolidating exercise against Florentine sandstone), compared to the CaCO3 nanoparticles (tested in our previous paper), which instead show excellent performance but only close to their first application. This means that over time, their resistance to drilling decreases, they wear much more easily (compared to SiO2 -treated sandstone), and tend to exhibit quite a significant surface abrasion phenomena. The experimental results highlight that the SiO2 consolidation efficiency on this kind of Florentine Pietraforte sandstone (having low porosity and a specific calcitic texture) seems to be higher in terms of water penetration protection, superficial cohesion forces, and an increase in surface resistance. Comparing the performance of SiO2 nanoparticles with commercial consolidants in solvents such as Estel 1000 (tested here), we demonstrate that: (A) the restorative effects are obtained with a consolidation time over one week, significantly shorter when compared to the times of Estel 1000, exceeding 21 days; (B) SiO2 nanoparticles perform better than Estel 1000 in terms of cohesion forces, also ensuring excellent preservation of the optical and color properties of the parent rock (without altering it after application)

Le risorse litiche della Lombardia Occidentale: formazioni geologiche, modalit\ue0 di acquisizione e circuiti di approvvigionamento tra Paleolitico e Neolitico

Western Lombardy is a relatively homogeneous territory, both from a physiogeographic and a morpho-structural point of view and it is characterized, all along the Prealps, by a general abundance of flint-bearing geological formations, which very often contains high-quality lithic raw materials. In spite of this very promising scenario for lithic raw material analysis, most of the previous researches paid little attention to the cultural implications of the circulation of lithic materials in prehistoric times. At the same time, in some cases the non-systematic nature of the previous researches led to a general underestimation of the importance of the lithic resources of this area when compared to other better known regions (ex. Veneto, Trentino). Preliminary data collected by two distinct research groups, one active in the provinces of Como and Lecco and the other in the area of the Varese lakes2, allowed to outline a first synthetic picture of the various Jurassic-Cretaceous flint-bearing formations. These show some lateral variations in the two areas investigated, which has to be related to the paleotopography of this sector of the Lombardy Basin, characterized by differentiated deep basins and pelagic structural highs, bounded by synsedimentary faults that ruled facial distribution

Il sito neolitico di Scandicci – via Deledda (Firenze)

Il sito neolitico di Via Deledda, scavato con un intervento di recupero nell’autunno 2002, è posto al margine sud-occidentale della piana alluvionale del bacino Firenze-Prato-Pistoia. L’evidenza emersa documenta una struttura d’uso, recuperata solo in parte, ricavata in terreno limo-argilloso. I reperti tra i quali sono presenti ceramiche, rara industria litica e resti faunistici provengono tutti da un acciottolato di base e permettono di riferire il complesso al Neolitico recente. Tale attribuzione è confermata da due datazioni radiometriche. In accordo con i caratteri espressi dalle produzioni recenti del Neolitico, a via Deledda compaiono aspetti formali riferiti agli ambiti di Ripoli /S. Maria in Selva e Ripoli/Fossacesia, di “Diana”, del VBQ o del Midi francese. Vengono qui presentati i risultati delle analisi geo-pedologiche, archeobotaniche, archeozoologiche e sugli impasti ceramici

I materiali e la tecnica pittorica utilizzati nella decorazione del Sarcofago delle Amazzoni

Durante il recente restauro del Sarcofago delle Amazzoni (IV sec. a.C.), rinvenuto a Tarquinia e attualmente conservato presso il Museo Archeologico Nazionale di Firenze, è stata realizzata un’indagine diagnostica diretta all’individuazione della tecnica pittorica utilizzata. Da questa indagine risulta che pittura consiste per lo più nell’applicazione a tempera del colore su una preparazione a base di cerussite. I risultati hanno portato a stabilire l’uso di pigmenti minerali naturali (ocra rossa, cinabro, goethite, cerussite) e artificiali (carbone vegetale e d’ossa o avorio, cuprorivaite) oltre a un colorante organico indigoide, la porpora

The actinobacterial colonization of etruscan paintings

6 pages, 4 figures, 42 references.The paintings fromTomba della Scimmia, in Tuscany, are representative of the heavy bacterial colonization experienced in most Etruscan necropolises. The tomb remained open until the late 709s when it was closed because of severe deterioration of the walls, ceiling and paintings after decades of visits. The deterioration is the result of environmental changes and impacts suffered since its discovery in 1846. We show scanning electron microscopy and molecular studies that reveal the extent and nature of the biodeterioration. Actinobacteria, mainly Nocardia and Pseudonocardia colonize and grow on the tomb walls and this process is linked to the availability of organic matter, phyllosilicates (e.g. clay minerals) and iron oxides. Nocardia is found metabolically active in the paintings. The data confirm the specialization of the genera Nocardia and Pseudonocardia in the colonization of subterranean niches.M.D.-H. was supported by a JAE Research Fellowship from the Spanish Council of Scientific Research and S.C. by a Juan de la Cierva contract. This research was supported with funding provided to the projects CGL2010-17183, 201030E011 and Consolider CSD2007-00058.Peer reviewe

Produzioni etrusche in ‘pietra fetida’ nell’Etruria settentrionale: materie prime e loro provenienza

Gli scavi di numerosi siti etruschi della Toscana sud-orientale hanno restituito sculture funerarie realizzate con un particolare tipo di calcare tenero chiamato ‘pietra fetida’ a causa del caratteristico odore che essa rilascia quando viene percossa. La mancanza di informazioni di dettaglio sulle ragioni per le quali gli Etruschi abbiano frequentemente utilizzato questa pietra, e sulle potenziali aree estrattive della stessa, hanno suggerito uno studio petrografico di questa roccia che ne chiarisca la natura ed i possibili luoghi di estrazione. La ‘pietra fetida’ è una roccia calcarea tenera, porosa e leggera, di colore beige e grana finissima, caratteri che ne permettono un facile riconoscimento. La sua originaria deposizione sarebbe da collocarsi nella Toscana meridionale durante la fase di regressione marina del Pliocene inferiore, in zone costiere al limite tra l’ambiente marino e quello continentale. Ciò sembra confermato dalla presenza di resti fossili di organismi di acqua dolce o salmastra come Ostracodi (Cyprideis) ed oogoni di Characeae . Questo litotipo talvolta viene citato come ‘sasso porco’ o, più impropriamente, come ‘tufo puzzolo’, ‘lapis suillus’, ‘stink stone’ ed infine ‘etruscite’ per l’ampio impiego che ne fecero gli Etruschi per la realizzazione di sculture, sarcofagi, cippi e urne cinerarie. Nel secolo scorso studi geologici dedicati alla stratigrafia e alla tettonica dei sedimenti pliocenici della Toscana meridionale, hanno consentito di individuare affioramenti di litotipi riconducibili alla ‘pietra fetida’ variamente associati a lignite, conglomerati, sabbie, argille e calcari organogeni, nei pressi di Chiusi, Montefollonico, Petroio, San Quirico d’Orcia e Pienza. Proprio per le sue caratteristiche di resistenza e di facile lavorabilità anche nei dettagli scultorei, questo tipo di pietra è stata utilizzata per la realizzazione di sculture anche di notevoli dimensioni; tra queste la più nota è la Mater Matuta, conservata nel Museo Archeologico Nazionale di Firenze. La ‘pietra fetida’ è stata utilizzata in gran parte per la realizzazione di sarcofagi e di urnette, alcune delle quali decorate a rilievo e spesso dipinte, mentre i materiali provenienti da stratificazioni sottili, quindi non adatte a ricavarne manufatti di grandi dimensioni, sono state usate per realizzare piccoli oggetti, tra i quali numerose basi per statuette in metallo. Manufatti etruschi in ‘pietra fetida’ sono attestati in una vasta area compresa tra Chiusi, Sarteano, Chianciano Terme e Pienza, ma sono stati rinvenuti anche in altri siti etruschi tra cui Murlo, Montalcino, S. Quirico d’Orcia, S. Giovanni d’Asso e Trequanda in provincia di Siena, oltre a quelle di Cortona e Pieve a Socana in provincia di Arezzo

Characterization of calcium carbonate nanoparticles with architectural application for the consolidation of Pietraforte

Laboratory-synthesized CaCO3 nanoparticles and their nanodispersion in 1,4-butanediol as a working medium have been first characterized and then tested on the surface of Pietraforte stone that forms the cladding of the bell tower of San Lorenzo. Both CaCO3 nanoparticles and their nanodispersion in 1,4-butanediol were characterized in the church in Florence, Italy by X-ray diffraction, thermal analysis, Raman, and Fourier transform infrared spectroscopy, scanning electron microscopy (SEM)/energy-dispersive X-ray (EDX) spectroscopy, and transmission electron microscopy/EDX spectroscopy. The Pietraforte sample surface, before and after CaCO3 nanodispersion treatments, was characterized by comparison of the porosity and specific surface area, capillary absorption, and surface hardness. An ultrastructural morphological investigation by SEM was also carried out, confirming and implementing the effective dynamics of the nanodispersion action. Lastly, differences in stone optical appearance before and after treatment were evaluated by colorimetric measurements. Considering the obtained results of the study, we conclude that CaCO3 nanodispersion in 1,4-butanediol is an effective restorative agent that prevents water infiltration in the stone, reduces stone disruption, and promotes its consolidation without altering its appearance. Finally, the long-lasting stability of the CaCO3 nanodispersion at ambient conditions makes it suitable for production and commercialization

Microscopic techniques (LM, SEM) and a multi-analytical approach (EDX, FTIR, GC/MS, Py-GC/MS) to characterise the decoration technique of the wooden ceiling of the House of the Telephus Relief in Herculaneum (Italy)

The House of the Telephus Relief in Herculaneum (Naples, Italy) is a Roman domus, buried by the eruption of Mount Vesuvius in AD 79. The house had a wooden roof with decorated ceiling, which was discovered in 2009. The roof represents an extraordinary archaeological find and, although it was found mainly disassembled, some of its wooden decorative panels are still almost intact. Some portions of the original polychrome decoration and traces of gilding are still preserved.Within the framework of the Herculaneum Conservation Project, a diagnostic study was undertaken to characterise the materials used in the polychrome decoration and to assess the technique used by Roman painters to decorate the ceiling.Micro samples (c. 500. μg) of paint were analysed with a multi-analytical approach. The micro-morphological characterisation of the pigments and the paint stratigraphy was assessed using light (LM) and scanning electron microscopes (SEM). X-ray microanalysis (EDX) coupled with SEM and Fourier transform infrared spectroscopy (FT-IR) were used to investigate the inorganic components. Gas chromatography/mass spectrometry (GC/MS) and pyrolysis coupled with gas chromatography and mass spectrometry (Py-GC/MS) were used to identify the binding media and other organic materials. The nature of the sediment, where the findings had been embedded, was also investigated.The acquired data revealed that a tempera painting has been applied. Egg was used as binder, whereas lime, red and yellow ochre, and caeruleum were used as white, red, yellow and blue pigments, respectively. The paint was directly applied onto the wood surface. Some decorations involved the application of gold leaf: unfortunately, no trace of the mordant or adhesives was found. The results also highlighted some issues related to the state of preservation of the artefact, thus contributing to the planning of conservation strategies