The ancient quarrying areas of the sandstones used in the UNESCO historical centre of Urbino (Marche, Italy) as inferred from geological, petro-chemical and physical-mechanical investigations

The Historic Centre of Urbino, UNESCO World Heritage (Marche Region, Italy): an Urban-Geological Itinerary Across the Building and Ornamental Stones

“…After the historical books of Francesco di Giorgio Martini (1477) and Bernardino Baldi (1587), Rodolico (1953) was the first author reporting a comprehensive description of the most used local building stones characterising the historic centre of Urbino. After this pioneer work, of the middle of the twentieth century, only few papers on the stones of Urbino were published, often focused to a single lithotype or one monument/archaeological context (Micheli 1983;Amadori 1985;Veneri 1994, 2003;Busdraghi and Wezel 2002;Amadori et al 2005;Fiora 2013;Santi et al 2019;Taelman et al 2019). In order to fill this gap, different architectural structures (walls, palaces, churches, monuments), dating back from the Roman time to the twelfth century, were described in the present paper considering both building and ornamental stones, including macroscopic features, structure, petrographic description, physical-mechanical properties and, when possible, matching their provenance area.…”

“…8), which were largely used (Fig. 2 see symbols of portals, pillars and colums) in several monumental portals of the historic centre of Urbino (Santi et al 2019). It is worth to note that, since the fourteenth century, skilful stonemasons from Sant'Ippolito were present in Urbino, importing the stone raw material from that area about 20 km ESE of the city (Fig.…”

“…8), locally named Sant'Ippolito Sandstones, is characterised by medium to thick, frequently amalgamated beds of medium to coarse-grained, graded and laminated sandstones with pelitic and more rarely conglomerate intercalations. Most of the sandstones used in the historic centre of Urbino for several monumental portals of buildings (Santi et al 2019) come from this area. They can be considered as lithic arenites and a very distinctive feature is the high content of bioclastic components (planktonic and benthic Foraminifera, shells of Gastropods, Bivalves and rarely brachiopods; between 80 and 90%; Fig.…”

“…Potential ancient exploited areas were identified in the hills surrounding Sant'Ippolito, where typical quarry-related shapes (scarps and steps too linear to be considered of natural origin) are still recognisable (Fig. 8; Santi et al 2019). In particular, the portal of the Palazzo Ubaldini-Ivarra (Fig.…”

“…It is worth to note that in this palace the lateral piers were sculpted with the same decoration that characterises the five portals of the adjacent Ducal Palace and the architrave shows the Spanish Ivarra family inscription. The Sant'Ippolito sandstones were also used to build the monolithic columns of the entrance of the Santa Maria della Misericordia old Hospital (Santi et al 2019) dating back to the fifteenth century (Fig. 2, circled letter g).…”