The hydrology in huge burial mounds built of loamy tills: a case study on the genesis of perched water tables and a well in a Viking Age burial mound in Jelling, Denmark

Abstract

For centuries a well was located on the top of one of the two Viking Age royal mounds in Jelling. This indicates that a perched water table had developed in the mounds. Perched water tables are well known in Bronze Age burial mounds due to the development of iron pans in the central part of the mounds, but it is unclear whether the genesis of the perched water table in the Jelling mounds is similar and due to iron pan formation or due to other soil forming processes. Thus, the purpose of this paper is to explain the formation of the perched water table in the mounds and the formation of a well on top of the North Mound. In order to do so, a series of borings into the two Viking Age royal mounds was carried out in 2009 offering insight into the soil composition and hydrology of the two mounds. Two of the boreholes were used for an in situ experiment to test the formation of the perched water tables and the well. The analyses of the borings and the in situ experiment indicate that a perched water table has developed at the bottom of the bioturbation zone in both of the two mounds and that the well was formed in an unrepaired intrusion into the mound as the result of the perched water table feeding the well with water. Despite large-scale excavations, the conditions for forming a well are still present in the mounds.

Keywords:

• Jelling
• burial mounds
• hydrology
• borings
• Viking Age

Acknowledgements

The investigations were conducted as part of the Jelling project housed at the National Museum in Copenhagen and funded by Bikubenfonden.