Drogheda, Ireland

Clients: Archaeological Development Services (Europe) Ltd

Author: Dave Mackie

MoLAS Geomatics travelled to Drogheda (north of Dublin, in Co Louth) to take archaeomagnetic samples from medieval pottery kilns (thought to be c 12th–13th century) located on the Old Mart site in the town. The archaeological excavation being carried out by Archaeological Development Services (Europe) Ltd had revealed three kilns and associated areas of medieval pitting. During the visit to the site, two MoLAS geomaticians sampled the two best-preserved kilns, which involved the recovery of well-fired areas of the feature by attaching plastic sample disks to them and careful lifting. Before removal, the sample disks were levelled and then marked to indicate the orientation of the sample in relation to true north (true north being determined using a theodolite-mounted gyro-compass). These measures provided the necessary controls required during their processing phase when the ‘fossilised’ indication of magnetic north contained in the sample since its last firing is measured. One of these kilns still contained wasters from the final firing, sitting on top of the central pedestal area and surviving kiln bars. The recorded samples were then processed by Mark Noel of Geoquest.

This site report is extracted from MoLAS 2004: annual review