Dating a flautist? Using ESR (electron spin resonance) in the Mousterian cave deposits at Divje Babe I, Slovenia

Abstract

The Divje Babe I site is located near Idrija in northwestern Slovenia. The cave contains Mousterian cultural artefacts left presumably by Neanderthals as well as numerous Ursus spelaeus teeth and bones. Among the Mousterian artefacts from layer 8 is a femur with four artificial holes thought to be a bone flute and the oldest known musical instrument. Sediment analyses indicate that the deposit represents at least six major shifts in climate, possibly interstadial/stadial cycles. Much of the phosphate in the sediment has been chemically mobilized. A 14C date for layer 2, the only Aurignacian layer, is 35 ± 1 ky B.P. Electron spin resonance (ESR) has been used to date fossils from archaeological sites, ranging from Lower to Upper Paleolithic. Teeth are dated by calculating the total accumulated dose represented by the enamel's ESR signal and the radiation dose rates in and surrounding the tooth. Five Ursus spelaeus teeth were analyzed from three layers associated with Mousterian artefacts. U concentrations are so low in the teeth that the ages do not depend on the uptake model, unlike most ESR age calculations. They do, however, critically depend on the external dose rate derived from the sediment, which depends strongly on the sediment water concentration and the inhomogeneities in the sediment surrounding the teeth. Assuming a time-averaged sedimentary water concentration of 10% gives minimum ages for any layer, while 25% sedimentary water may provide a maximum age for a sample given the radioactive elements in the sediment. Sediment inhomogeneities, however, have reduced the effective external dose rates for some teeth, and may have somewhat affected all the dates. The ESR ages limit the maximum age for the Mousterian layers and the flute to between 67 ± 10 ka and 82 ± 11 ka. The deeper layers are at least as old as the Last Interglacial, Isotope Stage 5. © 1997 John Wiley & Sons, Inc.