PLEISTOCENE FAUNAL GEOCHEMICAL AND SEDIMENTARY DOSIMETRIC ANALYSES AT POPŠIČKA PEĆINA 2, SERBIA: FACTORS THAT AFFECT ACCURACY FOR ESR DATING IN A NEW PALEOLITHIC SITE

In the Velika Morava Basin, ~ 40 km north of Niš, Serbia, the Cerjanska Cave complex formed in Mesozoic marine limestones within the Carpatho-Balkanides. Close to Meča Dupka, a cave intensively settled by Gravettian hunters, Popšička Cave is likely part of the same Cerjanska Cave complex system. With four entrances and 530 m of passages, Popšička Cave lies the foot of Mt. Kalafat at ~ 490-500 m amsl. In Popšička Cave, preliminary excavations in 2018 yielded two Paleolithic tools associated with many faunal remains. From Layer 3c, three mammalian teeth were collected for ESR dating, along with 19 sediment samples from five different sedimentary layers in order to calculate the sedimentary dose rates for each tooth with NAA. In the three teeth, internal dentinal U concentrations averaged from 7.9 to 10.6 ppm, while outer dentinal concentrations ranged from 13.0 to 13.7 ppm. In the sediment, the éboulis component generates very low β dose rates at 30-40 μGy/y and γ dose rates at 120-250 μGy/y. In Layer 3b, and in some horizons within Layer 3c, concentrations averaged < 1.4 ppm U, < 4.5 ppm Th, and < 0.6 wt% K. These horizons emitted sedimentary β dose rates at 100-150 μGy/y and sedimentary γ dose rates at 290-400 μGy/y. In other horizons within Layers 3c-3f, however, concentrations rose as high as 4.3 ppm U, 14.3 ppm Th, and 2.3 wt% K, emitting up to 440-500 μGy/y as sedimentary β dose rates and 1340-1580 μGy/y as sedimentary γ dose rates. In at least seven of these high dose zones, they appear to average from < 1 cm to > 3 cm thick, but patchy. These very high dose rates may indicate the presence of tepha-rich horizons, as reported recently at Golema Pešt, North Macedonia. Whether actually tephra or not, these very high sedimentary dose rates do require very detailed 3D modelling around each tooth to ensure accurate ESR ages. Thus, detailed sedimentary analyses will be needed to map the extent for each high dose rate zone.