Salt damage at Cleeve Abbey, England. Part II: seasonal variability of salt distribution and implications for sampling strategies

It is increasingly the case that assessments of large salt deteriorated objects, such as wall paintings, involve sampling and analysis to determine the object`s salt content. However, the usefulness of this is somewhat compromised by the fact that the salt distribution within the object is apt to change. This paper presents a new approach to salt sampling, using statistical and experimental design techniques to determine the degree to which analytical results are potentially affected by factors such as the sampling location and prevailing environmental conditions. A series of site investigations were undertaken to assess the spatial and temporal variability of the salt distribution within the thirteenth century wall paintings in the Sacristy at Cleeve Abbey, Somerset, UK. Analysis of variance (ANOVA) techniques were applied to the sampling data, and conclusively demonstrated that the salt content of the wall paintings varied significantly, not only with location, but also with depth, and over time. This has important implications for site assessment methodology, since analytical results can be strongly affected by factors such as the type of object under investigation, the sampling strategy, and the season during which the investigation is carried out.