Uranium-series dating of travertine from Süttő: Implications for reconstruction of environmental change in Hungary

Abstract

Terrestrial carbonate formations, such as travertines, speleothems and lake sediments, are important archives of terrestrial climate forcing. At the Süttő section in Hungary, a complex succession of travertine is covered by a loess-palaeosol sequence; both are high resolution terrestrial archives of climate and environment change. Uranium-series ( 230Th/U) dating was carried out to set up a more reliable chronological frame for the travertine. As the growth of travertine is very complex, pore cements may cause serious problems for precise dating. The state of alteration of primary spar and micrite was characterised by microscopic, cathodoluminescence and microprobe analyses. The travertine from Süttő showed homogeneous phases of primary calcite, minor micropores and rare pore cements. The carbon isotopic composition indicates that the source of carbon was a mixture of atmospheric and soil derived CO 2. Calculated water temperatures based on oxygen isotope data range from 22 °C to 31 °C. An attempt to provide an independent relative dating approach by palaeomagnetic techniques failed. 230Th/U ages were determined applying an isochron approach using the leachate/leachate method. As the travertine deposits have a dense structure, the bulk sampling method was successfully applied in determining uranium-series ages with much higher precision than former studies with alpha spectrometry. Travertines from Süttő yielded Mid-Pleistocene ages ranging from the antepenultimate glacial to the penultimate interglacial (310–240 ka). These results are in agreement with those from optically stimulated luminescence (OSL) dating and amino acid racemisation (AAR) dating of the overlying sediment indicating at least an MIS 7 age for the travertine.