Stefano Columbu

The Riace Bronzes are a pair of 5th century BC Greek statues, discovered in 1972 in the offshore of Riace Marina, south-eastern Calabria (Italy). A study conducted in 1995 by the Italian Central Institute for Restoration (ICR) highlighted a significant difference in the geochemical composition between the clays used for casting individual sections of the statues and those used for the terracotta pins with which they were welded. Considering that the clays used for assembling the statues are highly indicative of their installation site, and that numerous historical, literary, archaeological, and archaeometric clues suggest an original placement in the ancient Greek town of Siracusa (Eastern Sicily) for the two statues, in this work a comparison was made between the geochemical composition of the welding material and clays from the ancient production area of the town. According to geo-archeological data, this area was probably located in the alluvial plain between the mouth of the Anapo and Ciane rivers and the hill on which the Temple of Zeus Olimpio stands. The results show a surprising and significant correspondence between these clays and those used for the welding of Statue A and, in part, also for the restoration of Statue B. Furthermore, a review of literature data reveals a good correspondence between the mineralogical composition of the internal casting material of both statues and sediments present in the Sibari area (northern Calabria), the same used for the manufacture of the Auriga of Delphi. Finally, the analysis of the taphonomic characteristics of the bronzes and the geochemical analysis of the layered surface patinas, in relation to the hydrodynamic and geomorphological data of the Riace seabed, reveals a millennial primary deposition in different and much deeper seabeds. Aim of this study is to integrate the new data with a critical review of the most robust scientific evidence currently available in literature through an interdisciplinary geological-archeological approach, to yield a unified, coherent, and comprehensive reading of the history of the two famous statues within a single interpretive proposal.

Ammonium hydrogen phenylphosphonate forms a stable calcium phenylphosphonate dihydrate coating on marble, enhancing cohesion, reducing porosity, and restoring strength with minimal color changes, promising for the consolidation of carbonate stones.

This archaeometric study aims at characterizing the archaeological finds belonging to the lithic industry from La Calvera rock shelter (Camaleño, Cantabria) and at hypothesizing the possible provenance of each material. The site, located in the mountainous area of Picos de Europa National Park (more than 1000 m a.s.l.) close to the megalithic complex of Peña Oviedo, is characterized by the presence of hearths and charcoal remains, ancient pottery, and a rich lithic assemblage composed of siliceous rocks dating back to >8000 BP and linked to the first Holocene occupations of the Cantabrian Mountains. For the study of the rock shelter’s lithic assemblage, a multi-analytical approach was used: SEM-EDS and XRD analyses were performed to define the microtextural characteristics of samples and to identify the amorphous/crystalline phases; physical and mechanical tests were conducted to define the petrophysical properties (density, porosity, imbibition and saturation indexes, mechanical strength) of the samples. Preliminary data of chemical compositions, obtained by portable XRF, are also presented. The results show that the different siliceous materials (quartzite, cherts, hyaline quartz) can be distinguished through the basic analytical techniques used here. In addition, most of the archaeological samples have mineralogical and petrographic features similar to the natural samples coming from nearby outcrops, corroborating the hypothesis of a local material supply. The presence of local sources of useful raw materials could have favoured the site’s occupation. Finally, the diverse compositional and textural feature of the analysed materials result in different mechanical properties (porosity, density, hardness, workability), so they likely had different uses and technical functions.

This research is based on the characterization of ancient mortars from the Anfiteatro Flavio (Pozzuoli) dating back to the 1st and 2nd century CE through a multi-analytical approach involving macroscopic, mineralogical, petrographic, and chemical investigations. The goal that has been set is to deepen knowledge about mortar mix design, the provenance of used raw materials, and secondary minerogenetic processes that have occurred within ancient Roman mortars. Results show that: (i) raw materials for mortar preparation have a local provenance, i.e., Phlegraean Fields area; (ii) mortars can be considered as hydraulic; (iii) calcite presence could be due to a non-complete calcination process, an improper slaking or to exposition of materials to the subaerial environment; (iv) gypsum is due to calcite sulfation process; (v) halite presence is due to marine aerosol exposition. The achieved information testifies that, for at least two centuries, Roman builders considered the identified mortar mix as optimal for their buildings, but also contributes to the understanding of their technical skills and represents an important first step to planning future restoration operations.

The south-western Sardinian coast (Italy), in the sector between the small village of Chia (Domus de Maria) and the Piscinnì locality (Teulada), is one of the most interesting of the island, being characterized by a wide geodiversity, a complex history testified by several archaeological sites, rich ecosystems, and beautiful landscapes. This area is already famous as a seaside resort, but its rich geological heritage is totally unrecognized and the educational and touristic potential of its archaeological sites is widely undervalued. In this paper, we propose an itinerary in seven stages, each of which selected considering mainly its geology (geodiversity, scientific relevance of the geological features, and educational potential), and also the additional values as the presence of archaeological sites and/or of ecological diversity and/or touristic attractions. The aim of this work is to propose the study area as a geotrail since it represents a valuable geological (and not only) heritage to be protected, preserved, and valorized in the broadest meaning of the word. The following sites have been selected: Chia tower hill, showing interesting geological features and the Punic-Roman archaeological site of Bithia; Campana and Su Giudeu beaches with their dune system and the adjacent wetlands; Settiballas, near to the Chia-Laguna resort displaying a significant geological contact; Capo Spartivento rias and cliffs; Tuerredda beach and sand dunes; Capo Malfatano, a panoramic promontory made up of 460 million years old metamorphic rocks; and Piscinnì area, where a beautiful beach and a wide Punic/Roman sandstone quarry can be observed. In addition, the most panoramic points are overlooked by Spanish towers built during the 16th to 17th century. The study area is described from geological and archaeological points of view, after a detailed field survey, the petrographic characterization of the main rocks, and an overview of the scientific literature. The quantitative assessment of the geosite values has been also performed, revealing the high potential for scientific, educational, and touristic purposes. The main concerns related to the preservation and valorization of this geosite are also addressed. Finally, a discussion on the geosite assessment methods is proposed to contribute to the scientific literature on the geoheritage. The site-by-site description is reported at the end of the paper to be used as a field guide.

This study deals with the mortars and subordinately rocks collected from the archaeological site of Cap de Forma, that is a “Bien de Interés Cultural” located on a cape along the southeastern coast of Menorca (Balearic Islands, Spain). Cap de Forma consists of different structures belonging to different periods and civilization phases: a fortified settlement of Talaiotic age, built in cyclopean technique and including three rooms and a rainwater cistern; a nearby necropolis of tombs (cuevas) excavated into the cliff; a more recent site occupancy testified by plastering of the cistern; a house-fort (pecheña casa-quartel), a lookout point of the 17th–18th century. Compositional features and mineralogy of mortars and rocks were investigated by optical microscopy and X-ray diffraction. Physical properties (density, porosity, water saturation and water saturation coefficients and mechanical strength) were also determined. This work is aimed at characterizing these archaeologic remains to understand the building technique, the choice of raw materials and possibly their provenance, taking into account the age and civilization they belong to. Results indicate that cocciopesto-rich mortars were used in the cistern watertight and other ancient structures linking from a Roman age. The cocciopesto seems to derive from local pottery even if some evidence would suggest the contrary, whereas the source of the binder is definitely the local Mg-rich limestone. The house-fort was plastered with gypsum-based mortars in the 17th–18th century. The most likely source of raw gypsum was the island of Mallorca where some quarries were opened in the same period. Mechanical and physical tests reveal a strong state of decay that requires conservation actions. This work sheds light on a poorly studied monument, better constraining the different phases of its occupation. Some interesting questions, such as the cocciopesto provenance, are still open.

The Budello tower is located on a slight promontory from which it dominates the entire bay of Teulada and the towers of Sant’Isidoro, Pixinni, Malfatano and Porto Scudo. The tower, built in 1601 with irregular ashlars of local stones (mainly of magmatic-intrusive origin), has a truncated cone shape, an external diameter of 10,2 m and a height of 11,80 m. Inside it consists of a single room, with a domed vault and a central pillar, equipped with a embrasure, a fireplace, a trap door in the cistern, and a staircase, from which the square of arms was accessed. It was a torre de armas garrisoned by: 1 commander (in 1603), 1 artilleryman and 4 soldiers (1767), 1 artilleryman and 3 soldiers (1801), 1 artilleryman and 4 soldiers (1812). Although it underwent several restorations, documented as early as the years 1617-1619, the tower remained generally in good condition until the period 1763-1784, in which new restoration works were carried out including the closure of the parade ground with a classic parapet with gunboats and battlements. Other restoration works are carried out in 1808, 1819 and 1840. The tower remained in operation until 1843. Like all the other coastal fortifications, it was then definitively demilitarized with the Regio Decreto of 25 April 1867. Specific objectives of the research are the petrographic and physical-mechanical analysis of the stones and ancient mortars used in the construction of the tower, the structural analysis of the building and related geometric-constructive characteristics. The final intention is to understand the decay processes taking place on the tower both in terms of materials and static-structural aspects, and to envisage possible restoration interventions to be implemented aimed at its conservation.