Location of quarries of non traditional stony materials in the architecture of Madrid: the Crypt of the Cathedral of Santa María la Real de la Almudena

Abstract

The combination between petrological data and historical documentation sources is necessary to establish an accurate methodology for the location of the original quarries of the stony materials used in a determinate historical building. The petrographical and petrophisical data correlation combined with a multivariate statistical analysis, by means of similarity indexes of both the materials in the building and the probable source geological formations, allows the location even when the documental sources would he incomplete or lost, or when the source areas would be modified. The works of location of original quarries used in architectural heritage are important since they allow improving the works of restoration on a building by means of the possibility of using identical materials for substitution or reintegration of decayed elements. The establishment of the original areas also offers the possibility of obtaining unaltered semipiés to evaluate the state and processes of decay of the building as well as to use this rough material to test the effectivity and durability of protective arid consolidant treatments in the building and monuments. The aim of this work has been to characterize and to locate the origin of the stony material in the stonework of the Crypt of the Cathedral of Santa María la Real de la Almudena (Madrid). These stone types came from quarries located in Viana de Jadraque (Guadalajara, Spain) and in the central area of Portugal. These materials do not correspond with the traditional ones used in the city of Madrid and its presence is due to the opening of new ways of transport in the second half of the 19"' centuiy.