Organic geochemical evidence for the origin of ancient anthropogenic soil deposits at Tofts Ness, Sanday, Orkney

Lipid biomarker components of soils constituting three Orcadian archaeological fossil soil profiles were analysed. The combined assessment of lipid distributional and compound specific stable carbon isotope data enabled the identification of grass turves as the most probable material used in the formation of the anthropogenic soil deposits. Appraisal of 5β-stanol components indicated a faecal input to one of the soils which, on considering distributional evidence, was ascribed a human/porcine origin. Additional study of polar bile acids from this profile revealed a distribution exhibiting a predominance of deoxycholic acid indicating the primary faecal input to be mainly derived from humans although the minor occurrence of hyodeoxycholic acid, a characteristic component of pig faeces, attested to a limited porcine input.