Middle to Late Pleistocene environments based on stable organic carbon and nitrogen isotopes of loess‐palaeosol sequences from the Carpathian Basin

Abstract

Stable organic carbon and nitrogen isotopes can be used to interpret past vegetation patterns and ecosystem qualities. Here we present these proxies for two loess‐palaeosol sequences from the southern Carpathian Basin to reconstruct the palaeoenvironment during the past 350 ka and establish regional commonalities and differences. Before now, isotopic studies on loess sequences from this region were only conducted on deposits from the last glacial cycle. We conducted methodological tests involving the complete decalcification of the samples prior to stable isotope analyses. Two decalcification methods (fumigation method and wet chemical acidification), different treatment times, and the reproducibility of carbon isotope analyses were tested. Obtained results indicate that the choice of the decalcification method is important for organic carbon stable isotope analyses of loess‐palaeosol sequences because ratios vary by more than 10‰ between the wet chemical and fumigation methods, due to incomplete carbonate removal by the latter. Therefore, we suggest avoiding the fumigation method for studies on loess‐palaeosol sequences. In addition, our data show that samples with TOC content <0.2% bear increased potential for misinterpretation of their carbon isotope ratios. For our sites, C3‐vegetation is predominant and no palaeoenvironmental shifts leading to a change of the dominant photosynthesis pathway can be detected during the Middle to Late Pleistocene. Furthermore, the importance of further stable nitrogen isotope studies is highlighted, since this proxy seems to reflect past precipitation patterns and reveals favourable conditions in the southern Carpathian Basin, especially during interstadials.

Evaluation of geochemical proxies and radiocarbon data from a loess record of the Upper Palaeolithic site Kammern-Grubgraben, Lower Austria

“…For the measurement of δ 13 C org , bulk sediment samples were decalcified following the method of Pötter et al (2020). Of each sample, 150 mg was weighed into centrifuge tubes, treated with 25 mL of hydrochloric acid (HCl, 5 %), and kept in a water bath at 50 • C for 4 h. Subsequently, samples were washed with deionised water by repeated centrifugation.…”

Disentangling Sedimentary Pathways for the Pleniglacial Lower Danube Loess Based on Geochemical Signatures

“…The LPS were correlated on the MIS scale spanning from MIS 3 to 1. To ensure comparability to the reference regions, only (parts of) sections covering the same or comparable time frames were used (Marković et al, 2007(Marković et al, , 2020Obreht et al, 2015;Bösken et al, 2018Bösken et al, , 2019Tecsa et al, 2020;Pötter et al, 2021).…”

The Požarevac loess–paleosol sequence: a record of increased aridity in the south‐eastern margin of the Carpathian Basin during the last 350 ka

“…Present-day climate in northern Serbia is warmer and drier than elsewhere in the Carpathian Basin (Gavrilov et al, 2020), and a similar climatic gradient probably existed during pleniglacial intervals. Recent studies of the Ruma (Marković et al, 2006;Vandenberghe et al, 2014) and Irig (Marković et al, 2007;Pötter et al, 2020) loess sequences resulted in similar paleoclimatic and paleoenvironmental reconstructions. Together these studies suggest that the south-eastern margin of the Carpathian Basin was probably situated at the northern extent of a southeastern European 'warm' glacial province (Smalley et al, 2011;Lehmkuhl et al, 2021).…”