Dating of prehistoric caves sediments and flints using Be-10 and Al-26 in quartz from Tabun Cave (Israel): Progress report

There is an important need to develop additional dating methods beyond the C-14 limit and independent of thermoluminescence (TL) and electron spin res onance (ESR). We propose to apply the method of burial dating to prehistori c sites using the decay of in situ produced radioisotopes Be-10 and Al-26. The Tabun Cave, Mt. Carmel (Israel) has a sedimentary sequence which repres ents the type section for about the last 800,000 years in the Levant. The s ediments in the cave are mainly of aeolian origin and are rich in quartz. F lint tools are also found in the sediments. Sediment samples and flint tool s were selected from the same layer. Physical and chemical procedures to ex tract Be-10 and Al-26 atoms from the quartz fraction of the sediments and f rom the flint samples were developed, while measuring the natural Al levels as a monitor of the atmospheric component of the cosmogenic nuclides. AMS measurements were performed at the 14UD Pelletron Koffler Accelerator Labor atory, Weizmann Institute, and sensitivities of the order of 1 x 10(-14) in isotopic abundances for both Be-10 and Al-26 respectively (corresponding t o similar to5 x 10(5) atoms) were obtained. First, measurements of a number of Tabun Cave sediment samples and flints show that Be-10 and Al-26 analys es have the potential for dating prehistoric cave sediments, provided probl ems relating to the presence of relatively large amounts of stable Al can b e solved, as well as obtaining a better understanding of the burial history of the flints prior to being brought into the cave. (C) 2000 Elsevier Scie nce B.V. All rights reserved.