Physical and Chemical Analyses of Sediments from around Star Carr as Indicators of Preservation

Abstract This paper presents results of a project focused on investigating the deterioration of organic sediments in the area adjacent to the Mesolithic site of Star Carr. Physical and geochemical analyses of sediment sequences from 15 boreholes have been used to assess preservation status and potential of the deposits. The results indicate that severe acidification as a result of chemical oxidation of sulphide to sulphate has occurred at various locations around the site. This has adversely affected the preservation potential of these sediments. The acidification is strongly associated with a well-developed iron-sulphur (Fe-S) zone within the archaeological sediments, and is closely linked to annually fluctuating water tables. In contrast, some sequences had constantly low water tables and were oxidised throughout, but others with perennially high ground water showed only modest acidification. This offers the possibility of at least some areas of the Mesolithic Star Carr palaeo-lake edge being better preserved, although perhaps vulnerable to changes in the hydrological regime.