engleski

Complex investigation of the penultimate and last glacial cycles of the Süttő loess section (Hungary)

The loess-palaeosoil record in the Süttő travertine quarry, Hungary (47°44.26' N, 18°26.87' E, 256 m a.s.l.) provides an excellent high-resolution archive for palaeoenvironmental changes in the Northern part of the Carpathian Basin. Loess deposits up to 20 m thick cover the Süttő travertine complex, located next to the right bank of the Danube River. The loess is intercalated by two greyish stratified sandy loess horizons, three brownish steppe-like soils and a well developed pedocomplex in a palaeovalley infilling, including a reddish-brown palaeosoil, covered by a chernozem-like palaeosoil. Detailed luminescence dating was carried out using IRSL (infrared stimulated luminescence), OSL (optically stimulated luminescence) and IR-RF (infrared radiofluorscence) revealing more or less continuous sedimentation from MIS 6 to MIS 2. Independent age control is provided by radiocarbon dating for the upper part of the profile, by amino acid racemization (AAR) from the main loess units and by uranium-series(230Th/234U) ages correlating the travertine with MIS 7-8 from below the loess. The multi-dating approach provided an excellent chronological framework for the sediment succession at Süttő. High resolution granulometric, palaeomagnetic and biomarker investigations were carried out to improve our understanding regarding palaeoclimate- and environmental changes during the penultimate and last glacial cycles. Clay-, sand-, coarse sand content and “U ratio” were calculated from the results of high-resolution grain size measurements. The clay content showed excellent agreement with the magnetic susceptibility (MS) curve ; both are providing a good proxy for the local temperature and precipitation regime. The MS curve of Süttő shows a clear difference between loess and palaeosol horizons, indicating the alterations of arid and more humid environments. Correlation of Süttő relative palaeointensity (RPI) records to the high resolution RPI stack GLOPIS is not perfect in detail, but generally convincing. Mono Lake and Laschamp excursion are not recorded in palaeomagnetic directions at the Süttő loess palaeosol sequence. More detailed environmental magnetic investigations are in progress. In addition to these proxies n-alkane patterns derived from the loess and palaeosoils were examined to reconstruct the vegetation cover. All samples show a clear odd-over-even predominance (OEP), which is typical for cuticular plant leaf waxes. Different n-alkane ratios are compared, all of which show similar developing.

loess; palaeosol; Süttő; geochronology; grain-size; MS; n-alkanes

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