A combined OSL and ¹⁴C dating study of charcoal production in the sandy environment of Zoersel forest (N Belgium)

We investigate the potential of quartz-based OSL-dating for application to heated sandy sediments that are closely associated with the remains of charcoal production (charcoal kilns). This is particularly relevant for post1650 CE features, where 14C-dating lacks resolution. We first document the general OSL characteristics using large aliquots of sand-sized quartz.

Results from procedural tests indicate that the laboratory measurement procedure should allow reliable equivalent dose estimation. The scale of analysis is then reduced to smaller aliquots for all samples, each composed of 100–200 grains, as well as to single grains for eight heated samples. For one sample, both the small and single-grain ages are consistent with the 14C-ages obtained for charcoal fragments in the same sedimentary unit.

Also for three other samples, single-grains yield ages consistent with 14C-dating; all other OSL-ages are older although, for three of these samples, single grains and small aliquots yield results that are not significantly different. We discuss potential sources of inaccuracy for the OSL-dates, such as dose rate determination and homogeneous incomplete resetting.

The latter is the most difficult to assess and requires additional empirical data.