The Use of Pollen, Magnetic and Carbon Analyses in Identifying Agricultural Activity and Soil Erosion from the Neolithic to the Iron Age – A Study of Two Lake Sediment Cores from Jæren, South-Western Norway

Sediment cores from two small lakes, Alvevatn and Hanalandstjønn, both situated in the coastal heathland in Jceren, south-western Norway, were investigated with respect to microfossil analyses of pollen, spores and charcoal. The two lakes are situated close to prehistoric sites and monuments ranging in time from the Mesolithic to the Medieval Age. The microfossil analyses clearly reflect abrupt deforestation from closed mixed deciduous forest to heathland at approximately 3800 BP (ca. 2500–2200 cal BC). This event coincides with the generally accepted introduction of an agro-pastoral economy in the area at the Middle Neolithic II/Early Late Neolithic transition (MN II/ELN). However, at both localities, weak signals of agrarian impact are traced earlier by palynology. In recent years conclusions based on weak palynological signals have been criticised severely. In this investigation the tenability of the palynological method has been tested by applying independent methods to sediments from the same cores, viz. mineral magnetic and carbon analyses, which are likely to be proxy records for anthropogenic activity. The close agreement between the different methods support the conclusion that an agrarian economy was introduced prior to 4300 BP in the coastal heathland in Jæren.