Datación de eventos arqueológicos por luminiscenciaincendios y estructuras ligadas al fuego en Ciudad de Vascos

Abstract

In the historical development of the architectural heritage it is relatively frequent that fires have occurred that have affected at least part of the buildings or even that there are structures linked to the fire. Fires, from an archaeological point of view, may be linked to a specific human activity or to events whose historical relevance may be important, such as war or accidental fires. In the absence of historical documentation referring to them, the effects of fire can be recognized with relative ease since they often cause damage to stone materials of structures (eg stone blocks, bricks), from simple discoloration to considerable damages such as breakage , significant flaking or loss of mass. This damage potentially permits to study its effect: from its extent (to what areas of a structure or building it has affected) and its virulence (at what temperature have reached) until its dating (the moment in which they occurred). In recent years various procedures have been proposed and tested to know the temperature reached by these fires and there are several techniques that have allowed them to date, such as archeomagnetism. These procedures have mainly been applied to structures linked to fire, such as ovens and fireplaces. However, they have not been applied with the same frequency to accidental fires. In this work, a procedure for the dating and the study of the temperature reached in three types of fires related to the history of the site of the City of Basques (Navalmoralejo, Toledo) is presented. This site was an Andalusian city, founded in the 9th century and inhabited until the 12th century, whose most important architectural structures are dated in the 10th century. Three types of fires have been studied and dated (an oven, a deflagration and a theoretically intentional fire) by means of thermoluminescence (TL) and optically stimulated luminescence (OSL). These fires occurred on granite rock surfaces, in which the effects of fire caused thermoclasts, chromatic changes and porosity increases in the affected rocks, indicating that the temperature of these rocks exceeded 300ºC. The results of the analyzes showed that the fires reached temperatures around 450-500 ° C and also date the times they occurred, thus providing a new tool to date and contrast other methods of dating archaeological events.