Vaugneritic Rocks Used in the Renaissance and Baroque of the City of Salamanca: Geological and Heritage Singularity

Abstract Building and ornamental stones are important elements of cultural heritage and geoheritage, hence the importance of its study. Vaugneritic rocks used in the city of Salamanca (World Heritage City, 1988) have been a singular building material during the Renaissance and Baroque periods. They come from a small pluton (1.5 km 2 ) with complex zoning, located about 40 km west of Salamanca. Petrographically, they are quart-zmonzodiorites to quartz-monzonites, with notable variations in texture (from coarse- to fine-grained vaugnerite), biotite versus amphibole, and color index (from 19 to 44). Geochemically, the pluton shows a high degree of differentiation regarding other vaugnerites from the Iberian Massif, including rock facies up to 61% in SiO 2 . Its ambivalent technical and aesthetic characteristics have been used in monuments in the following senses: 1) as a durable material, used for plinths, pavements, and the rebuilding of the Roman Bridge; 2) as a selected material for the columns, jambs and lintels of Renaissance-style palaces, as occurred in the neighbouring city of Zamora, where another vaugnerite stone was used; and 3) for Proto-Baroque and mature Baroque doorways and arches due to the chromatic contrasts. Concerning the evolution of quarrying, first, the coarse-grained internal facies, outcropping as prominent boulders, were exploited for the large blocks of the classicist monuments; then, during the Baroque period, the stone quarrying work focused on the fine-grained rim facies, with sheeting joints, for basement ashlars. The continuity of the vaugnerite for almost four centuries contributed to the harmonization of the Salamanca varietas , an artistically high-valuated concept, but little recognized by this recurring stone.