La utilización del granito de los Santos en la ciudad de Salamanca

Résumé

The still active Los Santos granite quarries, about 50 km to the south of Salamanca, have been documented as a source material for many historical buildings in Salamanca. The excellent conditions of the natural outcrops, together with activation of the Vía de la Plata Roman route, are essential factors in explaining the competitive use of the Los Santos granite. Two different granite facies, both belonging to the Spanish Central System Batholith, have been distinguished: an external facies made up of biotite (± muscovite) and cordierite-bearing porphyritic monzogranites, and an internal facies, consisting of biotite porphyritic monzogranites, the latter one containing about 15% of biotite in volume. Heterogeneities are shown by both granite in quarries and monuments, microgranular mafic enclaves being the most remarkable feature in the internal facies, whereas internal-flow structures appear to be common at the contact of two facies. Geochemical classification and chondrite-normalized trace element patterns allow the correspondence between some samples from monuments and quarries to be checked. The stone from Los Santos was used from Roman periods onwards, the Roman Bridge being an emblematic monument. Later, two periods were particularly relevant: 1) the sixteenth century, in which the granite was used for columns of many Renaissance style monuments, as well as for pavements and steps, and 2) the twentieth century, the granite being used for the foundations of new buildings, and as ashlar material where a replacement has been required. The Los Santos stone seems to have witnessed the urban development of the Salamanca city during the 50�s and early the 60�s, when many buildings outside the city centre were built, combining the �golden� sandstone and the granite itself, as a result of a renewed awareness of the monumentality of Salamanca.