Preservation Status and Priorities for In Situ Monitoring of the Weapon Sacrifice in Illerup Ådal, Denmark

Abstract

Excavations of the southern part of a very rich sacrificial bog in Illerup Ådal, Denmark between 1950 and 1985 recovered approximately 15,000 Iron Age artefacts. At the time, 60 per cent of the area was left unexcavated and thousands of objects are now preserved in situ, but the present preservation status has not been investigated for approximately twenty-five years. Extensive in situ monitoring was carried out for one year in order to present a prioritized plan for further monitoring of the unexcavated areas, producing documentation of groundwater table variations, water quality and vegetation in the area. Results show that the remaining artefacts are generally well preserved in a waterlogged and anaerobic environment. However, in the north-eastern part of the bog, the groundwater table is too low even in a year when net precipitation and hydrological conditions were near normal. In the centre of the bog elevated salt concentrations have been measured in the groundwater.

Keywords:

• Iron Age
• bog
• monitoring
• waterlogging
• anaerobic environments
• Denmark

We would like to thank Jørgen Ilkjær for answering many questions regarding the excavation in 1975–85 and for assisting with slides, reports, and geological maps of the sacrificial bog. We greatly acknowledge Henning Matthiesen, Hans Huisman, Rune H. Kristiansen, and Bent Aaby for their time and assistance with various aspects of the study. Also skilled technical help from Ruth S. Nielsen and Lars Thomsen is acknowledged. We would like to thank the Royal Danish Academy of Fine Arts, School of Conservation in Copenhagen, the Fondation Idella, and the Augustinus Fonden for financial support. Finally, for the comments of the two anonymous reviewers, whose comments help improve the article.

Additional information

Notes on contributors

Anna K E Tjelldén

Anna K. E. Tjelldén is an object conservator with focus on in situ preservation. She is employed at the Department of Conservation and Environmental Archaeology at Moesgård Museum, Denmark.

Correspondence to: Anna K. E. Tjelldén, The Department of Conservation and Environmental Archaeology, Moesgaard Museum, Moesgaard Allé 20, 8270 Højbjerg, Denmark. Email: [email protected]

Søren M Kristiansen

Søren M. Kristiansen is associate professor at the Department of Earth Sciences, University of Aarhus, and focuses on geochemistry of groundwater, soils, and sediments.

Knud B Botfeldt

Knud B. Botfeldt is a lecturer in archaeological and natural history conservation at the Royal Danish Academy of Fine Arts, School of Conservation.