Contrasting Granite Types and Explanatory Models of its Historical Use in the City of Salamanca (Spain)

Abstract Over the centuries, three main granitoid types have been used in Salamanca city, from the following localities: (1) Los Santos, (2) Martinamor, and (3) Villavieja de Yeltes. A systematic geological comparison of these three main granite types was carried out, including the following aspects: (i) magma emplacement (border of a large batholith; sill-like body; and late rooted pluton, respectively), (ii) geochemistry and petrogenesis, (iii) petrography (biotite-bearing granite with porphyritic texture and bluish-grey color; tourmaline-bearing alkali-feldspar granite with nodular texture and white color; and two-mica granite with variable porphyritic texture and beige color, respectively), and iv) lithological and compositional comparison of the respective types and subtypes between quarry and monument. The use of these granites was connected to the following respective contexts: (1) the construction of the Roman Bridge, transporting the material through the Vía de la Plata, and its reintroduction in the Renaissance; (2) the pavement of the Roman Bridge in the 16th century, reinforcement of the Cathedral after the Lisbon earthquake (1755), and construction of the neoclassical Anaya Palace; and (3) construction of genuine eclectic monuments from Salamanca, after the railroad implementation. Additionally, two secondary granite types have been studied: The Porqueriza and Ledesma granites, which were used for the Roman Bridge in a particular way. The different properties of all the granites and their contrasting interaction of territory—quarry—monument trinomial combined with the varied construction history of Salamanca allows for a typification on the explanatory models of historical and distinctive use.