Luminescence Dating of Samples from Headland Archaeology Ltd. Excavations of Sites 25 and 28, A4/5 Corridor Improvement, Northern Ireland

Abstract

Optically Stimulated Luminescence (OSL) measurements have been conducted on 14 samples collected from two sites on the A4/5 Corridor Improvement in Northern Ireland. At site 25, near Drumcullion, samples were taken from two ditches. Samples from the outer ditch give dates of between 1230±60AD (at the bottom) and 1620±30AD (at the top), with a well defined stratigraphic sequence. These samples showed very little evidence of residuals, indicating that the material was probably fully bleached prior to deposition. Samples from the top of the inner ditch had considerable residual OSL signals, indicating they were not fully bleached at the time of deposition, consistent with these layers being infill from the digging of the outer ditch. The lowest sample showed little evidence of residuals and gives a date of 600±100AD. At site 28, near Kilawter, samples collected from the ditch also showed very little evidence of residuals. The lowest two samples show very similar ages of 530-580AD, with much younger material on top, with the top layer date of 1730±30AD