Study for restoration purposes about the obelisk located in "piazza della libertà" at ostuni (brindisi, Southern Italy)

Stone materials composing the St. Oronzo Rococ (local Baroque) obelisk, dedicated to patron saint of Ostuni in 1771 AD, were characterised. The monument is located in "Piazza della Libertà" at Ostuni (Brindisi, Southern Italy). The obelisk is composed of two different lithotypes, more or less pure Cretaceous limestone, with a variable porosity and biogenous component. Mineralogical, petrographical, geochemical and palaeontological and 87Sr/86Sr datation comparisons between finding lithotypes and Cretaceous limestones cropping out in four quarries already studied from some authors in the Ostuni sector, allow to ascribe obelisk samples to megabreccia quarry of Melpignano close to the ancient city wall of Ostuni. On the most used lithotype, recognised and sampled in the quarry, physical, mechanical and ageing tests have been carried out. These tests have evidenced the high porosity of the materials and have furnished some indications about utilisation and restoration methods.