After the soil samples have been brought into the laboratory, they are placed in water and sodium diphosphate overnight. This procedure means that the soil and organic material are not bound so strongly to one another and therefore become easier to sieve.
The dissolved soil samples are afterwards sieved manually and sorted into different sizes. Three samples are produced by this method: material over 1mm, between 1 and ½ mm and between ½ and Ÿ mm.
Here the final results of the sieving of the soil sample can be seen. The different size of the material in the individual samples is clearly visible. Material of approximately the same size is easier to investigate under the microscope.
Peter Steen Henriksen from the National Museum’s Natural Sciences Research Department analyses the cleaned borehole samples from the mounds under the microscope. Here the different types of seeds and other forms of organic material are counted and compared. Photo: Mads Dengsø Jessen.