Geological tools to interpret Scottish medieval carved sculpture: combined petrological and magnetic susceptibility analysis

Abstract

AbstractGeological surveys of 172 early and late medieval sculptured stones from central and western Scotland have been undertaken to determine the provenance of the materials used. Non-destructive petrological studies (including grain size, mineralogy distribution, and textural and structural characteristics) and magnetic susceptibility measurements are used to characterize the sculptured stones and potential source material. The results indicate that for the early medieval sculpture: (1) all the sculptured stones are sandstone with the exception of one siltstone and one granite; (2) the sedimentary rocks are consistent with sources in the Lower Old Red Sandstone of the area; (3) from within the Lower Old Red Sandstone, a number of different geological units have been used. For the late medieval sculpture, the results indicate that: (1) various rock types have been used including schist, slate and sandstone; (2) non-locally derived material is used extensively in some areas, suggesting a more developed network for procurement of raw materials. The analytical techniques used also provide additional information in the art historical interpretation of a number of carved stones by identifying carved fragments from the same monument.