Analytical study of the main door of Santiago church, Guadix, Granada

Abstract

The analytical study described on this paper has been made due to the request formulated by the priest of Santiago church, D. José Mª Ballesteros, through the Provincial Delegation of Culture of Granada. In view of the degradation of the main door front, the Instituto Andaluz del Patrimonio Histórico has been asked for technical advice on the possible treatment to be carried out to resolve the problems of this front. As a part of the technical study we have carried out the analysis required to determine the characteristics of the stone used, the possible causes of weathering and to evaluate the most adequate treatment products, in case that it is convenient to apply any one as a part of the conservation restoration works. As a first step we have carried out a visual inspection of the door front and the inside of the church, and then samples have been taken. These samples have been analyzed by means of: chemical analysis of main components, X Ray diffraction, mineralogic petrographic study and SEM observation. From all these determinations it has been deduced the possible causes and mechanisms of alteration. As previous phase to the evaluation of treatments, due to the high quantity of stone needed to make all the tests, we have proceeded to identify and find the quarry of origin of this stone; it is located in Bácor, a little village on the municipal term of Guadix, at 40 Km from it. Once the identification has been made with certainty, enough material has been extracted to prepare the samples used. It is very interesting to study this stone because it has been employed also on the Cathedral of Guadix and it will be able to extend the results obtained on the tests to this building.