ESR DATING HUMAN CULTURAL EVOLUTION AND CLIMATIC CHANGE DURING THE LATE PLEISTOCENE AT DIVJE BABE I, SLOVENIA

At Divje Babe I, the oldest archaeological site in Slovenia, a thick sequence of archaeological deposits house Mousterian artefacts, including hearths, Mousterian artefacts, and the Mousterian flute (Lau et al., 1997, Geoarchaeology 12: 507-536.), and more than 67,000 cave bear (Ursus spelaeus) skeletal remains. Numerous sedimentary characteristics, including cryoturbation, cryoclasis (congelifaction), secondary cementation, secondary aggregate formation, and éboulis formation, indicate that the cave has experienced strong climatic fluctuations. In order to date the Late Pleistocene layers, more than 30 independent standard ESR dates have been completed for 10 critical layers in the sequence. To assess the external dose rate, more than 120 independent NAA analyses were completed of the associated sediment to allow volumetrically averaged external dose rates to be derived (Blackwell & Blickstein, 2000, Quaternary International 68-71: 329-343.).

From 115 ± 7 ka to 104 ± 2 ka during Oxygen Isotope Stage (OIS) 5c, the cave fill was dominated by sediments formed under warm wet interglacial conditions and the first humans visited the site. Secondary cementation and aggregate formation predominate in these layers. Following a depositional hiatus, sedimentation resumed from 79 to 74 ± 11 ka (OIS 4/5a boundary), again under interglacial climates. Another hiatus followed lasting about 28 ky. From 46 ± 2 ka until after 36 ± 1 ka (OIS 3), the cave again received sediments, but éboulis formation, cryoturbation, and cryoclasis are the dominant sedimentary processes during slightly colder phases. These are intercallated with layers in which secondary cementation and aggregate formation suggest slightly warmer and wetter conditions. During this period of strong climatic fluctuations, four interstadials and five stadials can be recognized in the sediment. Humans again visited the cave intermittently leaving behind Mousterian artefacts and the flute.