Early Anthropogenic Soil Formation at Tofts Ness, Sanday, Orkney

Abstract

A buried, dark coloured loam soil horizon embedded between calcareous wind blown sand deposits is identified in three areas of the Tofts Ness landscape. The close association with early settlement sites and enhanced total phosophate levels suggests that this soil horizon is anthropogenic in origin. Radiocarbon dating and stratigraphic relationships with settlement sites indicate that the horizon is associated with Bronze Age cultural landscape activity and may have commenced formation during the Late Neolithic period. Horizon formation is interpreted through a synthesis of thin section micromorphology, stable carbon isotope analysis and analysis of free soil lipids. These analytical methods indicate that formation was through the application of grassy turf material together with domestic waste midden, while cultivation was moderately intense as evidenced by the movement of fine material through the horizon. The closest parallels to these soil horizons are the cultural plaggen soils of continental north west Europe, with the Tofts Ness soils amongst the earliest known of these soil types. Application of this manuring technique at Tofts Ness allowed arable activity in what was a highly marginal farming environment; emerging evidence from other parts of the Northern Isles of Scotland suggests that these manuring strategies were commonly used in early arable systems.