Nondestructive examinations on the Viking Fortress Trelleborg

Arne Stamnæs has conducted investigations in part of Trelleborg using a magnetometer and ground-penetrating radar in early February 2022. Currently, Trelleborg is awaiting the results of these investigations.

MAGNETOMETER AND GROUND-PENETRATING RADAR
A magnetometer measures small magnetic anomalies in the ground, which can indicate the presence of metal, ceramics, burnt materials, or waste piles. After these investigations, the findings need to be compared with other research. The ground-penetrating radar sends radio waves into the ground and measures how the energy is reflected back, revealing structures beneath the ground such as pits, cooking pits, stone constructions, and more.

The magnetometer detects magnetic materials, while materials that conduct electricity are detected by the ground-penetrating radar. Together, these two types of investigations create a detailed map of the subsurface. This allows for documenting archaeological structures and mapping how the landscape has changed over time. Subsequent soil samples can provide further knowledge about soil conditions and the water level of the river during the Viking Age.

NEW INVESTIGATION METHODS AND POUL NØRLUND
With the new investigation methods, we can precisely identify areas where excavation is necessary, and future discoveries will provide valuable insights into the everyday life of Viking warriors at the fort.

The investigations aim to demonstrate how the fort and its surrounding area were used, as well as how access to the fort was achieved during the Viking Age. Were the Vikings only able to reach Trelleborg by sea, or was the fort also accessible from the land?

Trelleborg was originally excavated by Poul Nørlund between 1933 and 1942. The findings were groundbreaking but were carried out using methods that are now partially outdated. Furthermore, several areas within the fort have only been sporadically or not at all investigated. This applies to parts of the inner ring fort, the area towards the river, the space in front of the fort, and the area surrounding the reconstructed longhouse.

In connection with the application of Danish Viking forts for inclusion on UNESCO's tentative list, non-destructive investigations have also been conducted on the other ring forts.

COLLABORATION REGARDING THE INVESTIGATIONS
The investigations are part of a larger, future interdisciplinary research project that will eventually include investigations of the surrounding areas, the use of LIDAR, strontium analysis, place name research, metallurgical investigations of the tool inventory, and more.

The investigations are carried out in collaboration between Trelleborg, the National Museum, and Arne Anderson Stamnes from NTNU, the Museum of Natural History and Archaeology, Department of Archaeology and Cultural History. The investigations are supported by the Krogager Foundation, NTNU, the National Museum Research Grant, and Slagelse Municipality's rural district fund.