Reconstructing Quaternary vegetation history in the Carpathian Basin, SE-Europe, using n-alkane biomarkers as molecular fossils: Problems and possible solutions, potential and limitations

Abstract

Over the recent years there has been increasing fossil charcoal and malacological evidence from loess-palaeosol sequences in the Carpathian (Pannonian) Basin that call into question the traditional paradigm of treeless full glacial palaeoenvironments. In order to contribute to this discussion we focus on plant-derived n-alkanes and evaluate their potential to serve as biomarkers for the reconstruction of vegetation history during the last glacial cycle. Recently published initial results show a strong degradation effect on the alkane pattern hindering the direct application of frequently used alkane ratios like nC31/nC27, which are in literature often used as vegetation proxies (grass vs. tree). In this paper we therefore introduce for the first time an end member model taking into account the different degree of organic matter (OM) degradation in soils/loess. The model is applied to the Crvenka loess-palaeosol sequence on the Baeka Loess Plateau (Vojvodina, Serbia) at the confluence of the Danube and Tisa Rivers. The results show grass dominance during the whole last glacial cycle. Some few trees likely contributed to the vegetation cover during glacial periods and during the Holocene, but not during the last interglacial and the Marine Isotope Stage (MIS) 3 interstadial. The reconstructed vegetation history is in agreement with previous malacological and charcoal findings as well as with climate and biome modelling results.