The radar signatures and age of periglacial slope deposits, Central Highlands of Germany

Determining the age of periglacial slope deposits (head) in the Central Highlands (Mittelgebirge) of Germany is a research challenge because of the lack of dateable organics and the contentious role of the Laacher See Tephra (LST) as a dating indicator. Ground penetrating radar (GPR) and cores were used to establish the subsurface stratigraphic relationships between the peat deposits of two bogs (Totenauer Moor, Bayerischer Wald and Schwarzes Moor, Rhön) and underlying head deposits in order to provide minimum ages for the head. Radiocarbon dates were obtained from peat bogs overlying the head in the Bavarian Forest, while in the Rhön (Schwarzes Moor) LST was found bedded in the peat above the head indicating that the latter therefore, is older than Alleröd. Radar profiles show that the head is a stratigraphically continuous, not interbedded, unit beneath the peat. The lowest peat at Totenauer Moor, immediately above the Upper Head, was dated at 11,550 ± 260 yr BP thus establishing the minimum age of the Upper Head as being older than Bölling and perhaps even Older Dryas, but not Younger Dryas. The LST shards were not deposited contemporaneously with the head but were incorporated by bioturbation and mass movements. This study demonstrated the utility of GPR as a tool for imaging head deposits.