A geohistorical retrospective analysis of cultural heritage buildings: the case of Mosta Dome, Malta

Geohistorical retrospective analysis attempts to establish the location of industrial mineral extractive sites. This paper is based on a study of the Rotunda of Mosta, a feat in architectural engineering structures inspired by the Pantheon in Rome. It was designed and erected in local Lower Globigerina Limestone. This Neoclassical church is the third largest unsupported masonry dome in the ecclesiastical architectural history of Europe. According to oral tradition, the architect Giorgio Grognet de Vassé had opted to use limestone from Ta’ Vnezja in the limits of Mosta. A retrospective analysis of the geological fabric used in the construction of the church proves that the limestone was not from this area but from a locality in its close proximity, namely Ta’ Qali. Although the geology present at both sites was considered similar at the time of erecting the church and the respective relative suitability for use as dimension stone was known, the limestone at Ta’ Vnezja is lithologically different from Ta’ Qali. At both these localities quarries were sunk in their lithostratigraphic sub-formation namely the Middle Globigerina Limestone Member and the Lower Globigerina Limestone Member respectively.