Multi-analytical study of the medieval wall paintings from the rupestrian church Grotta del Crocifisso at Lentini (eastern Sicily): new evidence of the use of woad (Isatis tinctoria)

AbstractThis study presents the results of the examination and characterisation of the wall paintings that decorate the rupestrian church named Grotta del Crocifisso, which is located in the territory of Lentini (eastern Sicily, few tens of kilometres from Catania and Syracuse). The earliest mural paintings in the church date back to the twelfth century AD. A multi-analytical approach was adopted for the characterisation of stone materials, secondary degradation products, and pigments. For this purpose, the following techniques were used: reflected light microscopy (RLM), polarised light microscopy on thin sections (PLM), X-ray powder diffraction (XRPD), mercury intrusion porosimetry (MIP),…

XRF ANALYSES ON MOSAIC TESSERAE OF THE PALATINE CHAPEL OF PALERMO

Geochemistry of phosphatic nodules as a tool for understanding depositional and taphonomical settings in a paleolithic cave site (San teodoro, Sicily)

Interpreting depositional settings of cave sites is generally problematic, especially in absence of palaeontological/archaeological evidence. This is the case of some deposits at San Teodoro Cave (Sicily), a key site for the Mediterranean Palaeolithic. In a stratigraphic level interrupted by a carbonatic concretion, phosphatic nodules are present only in the part enclosed between the concretion and the cave wall. The discovery of these nodules combined with the punctual lack of fossils had initially suggested an erosion phenomenon and subsequent formation of nodules at a vadose level. Here we show the usefulness of an integrated, geochemical-palaeoecological approach in defining stratigraph…

First evidence of Pleistocene ochre production from bacteriogenic iron oxides. A case study of the Upper Palaeolithic site at the San Teodoro Cave (Sicily, Italy)

Abstract The use of iron pigments is well documented in the archaeological horizons of the different parts of the world since the Middle Pleistocene. The mineralogical and chemical composition of the pigments allowed defining, in most cases, their inorganic origin, which were then used after a limited transformation and manipulation. The use of a biogenic ochraceous pigment and its manipulation has recently been described in a late Holocene archaeological horizon of the American continent. Here we describe the earliest case of archaeological use of ferrous pigment produced by iron-oxidising bacteria (FeOB), the first identified in a European Epigravettian (late Upper Palaeolithic) layer, at…

INDAGINI SPERIMENTALI SU MALTE TRATTATE CON SILICATO DI LITIO NANODISPERSO DA UTILIZZARE PER STUCCATURE DI MATERIALI LAPIDEI COMPATTI

In questo lavoro di ricerca, sviluppato all’interno della tesi di laurea magistrale in Conservazione e Restauro dei Beni Culturali presso l’accademia Galli di Como con la supervisione della restauratrice Gisella Bianconi, si è sperimentato l’uso del silicato di litio come additivo per il miglioramento delle prestazioni di malte a base di leganti inorganici, e in particolare calci aeree e idrauliche, utilizzate nel restauro dei materiali lapidei. Spesso per le stuccature di materiali lapidei compatti vengono utilizzate malte con leganti organici, ed in particolare di tipo epossidico, che offrono certamente ottime proprietà meccaniche e un’eccellente adesività, garantendo al contempo una acce…

Lithium silicate admixture in mortars to be used as putty for limestone

Marble is a very common material in artworks for its softness, relative isotropy and homogeneity and its characteristic waxy look that gives "life" to sculptures. Even if in geology the term "marble" refers to metamorphosed limestone, commonly the term ‘marble’ is used more broadly encompassing hard unmetamorphosed limestone that can be polished assuming a glossy aspect. In the restoration field when marble artworks have cracks that alter the smoothness of their surface, a putty is used to fill them, for both aesthetic and conservative reasons. Putties usually consist of epoxy resin mixed with marble powder. The use of a synthetic resin raises some doubts on compatibility and durability of …