LINKING THE LOESS – PALEOSOL RECORD OF PLEISTOCENE CLIMATE IN SERBIA WITH THE EXPANDING CENTRAL EUROPEAN AMINOSTRATIGRAPHY

Numerous loess-paleosol sections have been investigated along Fruska Gora in Vojvodina, Serbia, and a detailed paleoclimate record for the mid to late Pleistocene is emerging for south-central Europe. In order to test regional stratigraphic correlations and correlate with loess sequences studied elsewhere in central Europe, we sampled fossil gastropod shells from loess units and measured D/L amino acid ratios in an effort to expand our evolving European aminostratigraphy into the Serbian loess region. Stari Slankamen, the longest continuous section that we have sampled, includes eight interglacial paleosols and intervening loess units recording alternating warm-moist and cool-dry climate oscillations. We also sampled loess-paleosol sections at Ruma, Petrovaradin, Irig, Miseluk, Kula, and Titel.

Gastropods sampled include the genera Helicopsis, Trichia, Pupilla, and Succinea. Using reverse-phase liquid chromatography, we measured D/L ratios in 10 amino acids. Our analysis and interpretations focus on D/L aspartic acid, glutamic acid, valine, phenylalanine, and allisoleucine/isoleucine ratios (aIle/Ile). The range of racemization rates exhibited by these amino acids allows us to optimize resolution for different time periods. According to the present chronostratigraphic model, loess L1 and paleosol S1 were formed during glacial cycle B, corresponding with marine oxygen-isotope stages (MIS) 2-5. Horizons within L2 and S2 correspond with glacial cycle C and MIS 6 and 7, respectively. S2 is a double paleosol and is correlated with the Hungarian BD paleosol pair on the basis of racemization data. Loess and paleosol units L3 and S3 correlate with glacial cycle D and MIS 8 and 9, respectively. Older units in the sequence are similarly correlated with the Hungarian aminostratigraphy, although few outcrops are available for sampling and comparing data from stratigraphically lower units.

Present-day ground temperatures in loess of Hungary and Serbia show a significant increase in temperature from the northwest to the southeast. Mean annual temperature at one-meter depth rises from 10.5 °C near Budapest to 13.5 C in parts of Vojvodina. This increase in temperature explains the more rapid rate of racemization and the higher D/L ratios in loess of Vojvodina relative to the equivalent age loess units in Hungary.