Uranium-series age determination of travertines from the site of Vértesszöllös, Hungary

The site of Vértesszöllös has yielded a pebble-tool industry, a fragment of the cranium of a primitive form of Homo sapiens, and a vertebrate fauna indicative of the Biharian faunal stage. We have analyzed the travertines under- and overlying the hominid-bearing marl. All the samples are significantly contaminated with detritus, so that calculated U-series disequilibrium ages provide upper limits to the true age. The individual samples, when corrected for a possible initial 230Th/232Th ratio of 1·5, give an average age of 211 ± 13 Ky. By fitting the data to a model consisting of a mixture of authigenic and detrital components, we obtain an age of 162 −62+73 Ky. The travertines appear to have been deposited over a span of about 40,000 years centred at about 185 ± 25 Ky bp. This places their deposition near the beginning of isotope stage 6, much younger than has been generally believed.