ESR DATING IN THE BALANICA CAVE COMPLEX, SERBIA: TRACKING HOMININS AND PALEOLITHIC CULTURES IN THE MIDDLE PLEISTOCENE

Overlooking the Sićevo Gorge, the Balanica cave complex lies ~ 15 km east of Niš, Serbia at ~ 335 m amsl. Both Mala Balanica (MB) and Velika Balanica (VB) yielded Middle Pleistocene mammal fossils, Middle and Lower Paleolithic artefacts. VB served as a permanent habitation, especially in Layers 2-3, where lithic artefacts, hearths, and charcoal particles have occurred, but MB likely hosted visits from smaller groups. MB's Layer 3b yielded a Homo heidelburgensis mandible. Both caves have matrix-supported conglomerates, where sandy, clayey silts with éboulis up to 1.5-2.0 m³ in some layers. In VB, reddish silty clay and éboulis in Layers 2a-2c overlie the brown, clayey silts and silty sands forming Layers 3a-3c, that include hearths. In VB, Layer 4c's several four collapsed stalagmitic flowstone floor reflect subsidence before MIS 11, while éboulis that show diagenetic alteration, weathering, root-etching, and post-dispositional carbonate rims, and lens with secondary carbonate cements that solidify them. Most of VB's layers sitting stratigraphically above the MB's deposits. Two from Layers 2c-3a in MB and 21 teeth from Layers 2a-4c4 in VB have been by ESR standard and isochron analyses. After > 80 associated sediment samples were measured by NAA, the time- and volumetrically averaged sediment dose rates in the caves were calculated using a 3D multi-component model using éboulis and cobble sizes and positions as mapped around each tooth from the total station, photographic, and excavation data. U concentrations in the enamel ranged from 1.0 to 9.1 ppm, while dentines ranged from 38 to 95 ppm, making it essential to understand the U uptake rates by doing isochron and coupled ESR-⁴³⁰Th/²³⁴U analyses to improve the ages' accuracy. Isochron analyses suggest that secondary U remobilization has occurred in at least one teeth. Ages for both caves show the Balanica caves complex continued to receive sediment for > 400 ky from the early Middle to later Pleistocene.