Morfologiska studier av arkeologiskt trä under järnurlakning

Abstract

A high iron content is often found in archaeological wood recovered from marine environments. During the years of burial, iron will be diffused into the wood matrix which can cause further damage to the wood after excavation. During previous studies, iron has been identified in the cell structure as black particles. This thesis investigates if it is possible to document the extraction of iron from thin cuts with light microscopy. The material used for this experiment comes from an untreated archaeological oak plank of the 17th century warship Svärdet from Sweden. Results from previous studies show that the surface of the timbers from Svärdet have high iron content. The extraction was done with two commonly used chelating agents called DTPA and EDTA, where DTPA has been proven to be a stronger chelating agent. Thin cuts were sampled from the oak plank and black particles where then located and documented by light microscopy. The cuts were placed in microtubes, containing either a solution of DTPA or EDTA. After 13-14 days, the cuts were documented again. The observations revealed that it is possible to document the extraction process by using light microscopy. The results correlate to previous studies that indicates that the black particles identified in the cell structure is iron. The results also showed that DTPA was more efficient in removing the black particles than EDTA. Some damage on the cuts were observed but further research would be needed to determine whether it comes from the complexation or from handling of the cuts. Furthermore, the results indicate that this method may be useful when evaluating new methods for extraction of iron. Title