A critical re-evaluation of palaeoclimate proxy records from loess sections in the Carpathian Basin

Abstract

In the Carpathian Basin, loess is the most important archive for inferring Quaternary palaeoclimate variability. Palaeoclimate inferences based on magnetic susceptibility and grain-size distribution, as the most commonly used palaeoenvironmental proxies for the Carpathian Basin loess indicate colder and drier climatic conditions during glacials compared to interglacials with soil development under warmer and more humid climate. However, with an increasing number of studies using novel proxies in loess research, such a traditional understanding of dry and cold glacials and humid and warm interglacials in the Carpathian Basin has been questioned. For example, mollusc based climate reconstructions suggest generally warm and very dry glacial summer conditions with mean July temperatures up to 21 ̊C for the southern Carpathian Basin. Results based on stable carbon isotopes strongly oppose such high summer temperatures, but studies based on n-alkanes are in general agreement with the mollusc data when it comes to the vegetation reconstruction indicating mostly steppic Topic 8: Climate change, climate dynamics and paleoclimate – 8c) Loess systems and the reconstruction of Pleistocene climate dynamics
164conditions. However, n-alkane studies contradict warm and dry glacial conditions as indicated by mollusc-based reconstructions, pointing instead to cold and relatively humid glacials. Consequently, the current stage of the art of the palaeoclimate reconstructions from loess in the Carpathian Basin is rather inconsistent.In order to obtain a better understanding of the existing palaeoclimate data from the Carpathian Basin loess, we have re-evaluated and re-interpreted the available data. We discuss and propose a coherent interpretation of rock magnetic, grain-size, malacological, stable carbon and nitrogen isotope, n-alkane and bacterial membrane lipid data for the last glacial cycle loess in the Carpathian Basin. We can show that glacial conditions in the Carpathian Basin led to a notable increasing North-South gradient in temperature and an even stronger expressed decreasing trend in humidity, and that most of the biomarker proxy data conducted in loess for the very dry southern part of the Carpathian Basin show a strong bias towards arid conditions. Glacial conditions were drier and colder than previously proposed, but notably warmer than in other parts of Western, Central, and Eastern Europe. The vegetation cover was mainly characteristic of steppic environments during both glacials and interglacia

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Bibliography

Obreht, I., Zeeden, C., Hambach, U., Veres, D., Markovic, S., Lehmkuhl, F. (2018): A critical re-evaluation of palaeoclimate proxy records from loess sections in the Carpathian Basin. Geobonn 2018, Living Earth, 2-6 September 2018, Bonn, Germany