Mona Court-Picon

The timing of aeolian events near archaeological settlements around Heidebos (Moervaart area, N Belgium)

At the locality of Heidebos (Moervaart area, N Flanders, Belgium), a sedimentary core was taken in the Maldegem-Stekene coversand ridge and dated using optically stimulated luminescence (OSL). The study aimed at contributing to an improved understanding of the evolution of the physical landscape around archaeological settlements in this area. The core comprised a 7 m thick series of laminated and massive aeolian sands, in which several organic layers were intercalated. From this sequence, 11 samples were collected for quartz-based SAR-OSL dating; an internally consistent dataset was obtained. The ages of the lowermost 1 m of the sedimentary sequence (15.5±1.1 ka and 17.3±1.3 ka) imply that these sediments may represent the time-equivalent deposit of a deflation phase that occurred during the Late Pleniglacial and led to the formation of a widespread desert pavement, regionally known as the Beuningen Gravel Bed. However, a significant part of the sediments (at least 4 m) was deposited later, i.e. during the Allerod and/or the Late Dryas. As such, the results allow establishing the genesis of the coversand ridge at the Heidebos locality on the basis of direct age information. The relatively high sedimentation rate and the absence of extensive soil formation in the record reflect periods of pronounced aeolian activity and landscape instability during the Late Glacial, which provides part of the environmental framework for human occupation in the area.