Credit: Forrás: Kovács János
Paleoenvironment and Paleoclimatology research group
The Research Group focuses on deciphering paleoclimates and paleoenvironments on different time scales ranging from the Quaternary to deep in the past using geochronological, geochemical, and paleontological multi-proxy approaches. Our highly interdisciplinary research is conducted in close collaboration with researchers outside of our institute.
Pliocene - Early Pleistocene continental climate and vegetation in Europe based on stable isotope compositions of mammal tooth enamel and terrestrial sedimentary records
There is an increasing need for paleoclimate records from continental settings to better understand the climatic changes during critical periods such as the Pliocene and Early Pleistocene. This research topic focuses on the oxygen and carbon isotope compositions of mammalian tooth enamel for the Pliocene and Early Pleistocene of South and Central Europe to reconstruct the spatial distribution and temporal changes of the vegetation and oxygen isotope composition of precipitation (δ18Oppt). All δ13C values indicate C3 ecosystems and reflect major changes in the water use efficiency and/or in the prevailing humidity. The reconstructed major floral types range from woodland to woodland‒mesic grassland in all of the investigated regions. The carbon isotope compositions of fossil mammal teeth demonstrate that the spatial distribution of vegetation was broadly similar to those of the present-day for the Early/Late Pliocene – Early Pleistocene, with the most “closed” vegetation in Central and Northern Italy, while open mesic grassland vegetation covers can be reconstructed for the Iberian Peninsula, Massif Central region (Central France) and the Carpathian Basin. The calculated δ18Oppt values give a negative temporal shift of about 1–1.5‰ from the Early Pliocene to Late Pliocene – Early Pleistocene in three regions (Iberian Peninsula, Central Italy, Carpathian Basin), potentially representing a 1.5–3.0 °C decrease in mean annual temperatures (MAT) over time. In the Massif Central region and the Carpathian Basin, the δ18Oppt values are almost the same for the Late Pliocene and Early Pleistocene, while in Northern Italy the values decreased over that period. The δ18Oppt values are in the range of present-day δ18Oppt values over the Early Pliocene and somewhat lower than present-day values for the Late Pliocene - Early Pleistocene in most of the regions. Because most other proxies indicate warmer than present-day climate for the Early Pliocene and similar to present-day climate for the Early Pleistocene, the δ18Oppt values are generally lower than expected, which can be partially explained by local effects.
Szabó, P., Kovács, J., Kocsis, L., Vennemann, T., Domingo, L., Újvári, G., Halmai, Á., Pirkhoffer, E. & Codrea, V. (2022) Pliocene - Early Pleistocene continental climate and vegetation in Europe based on stable isotope compositions of mammal tooth enamel. Quaternary Science Reviews 288, 107572.
Kovács, J., Németh, K., Szabó, P., Kocsis, L., Kereszturi, G., Újvári, G., & Vennemann, T. (2020) Volcanism and paleoenvironment of the Pula maar complex: A Pliocene terrestrial fossil site in Central Europe (Hungary). Palaeogeography, Palaeoclimatology, Palaeoecology 537, 109398.
Szabó, P., Kocsis, L., Vennemann, T., Pandolfi, L., Kovács, J., Martinetto, E. & Demény, A. (2017) Pliocene-Early Pleistocene climatic trends in the Italian Peninsula based on stable oxygen and carbon isotope composition of rhinoceros and gomphothere tooth enamel. Quaternary Science Reviews 157, 52–65.
Kovács, J., Szabó, P., Kocsis, L., Vennemann, T., Sabol, M., Gasparik, M. & Virág, A. (2015) Pliocene and Early Pleistocene paleoenvironmental conditions in the Pannonian Basin (Hungary, Slovakia): stable isotope analyses of fossil proboscidean and perissodactyl teeth. Palaeogeography, Palaeoclimatology, Palaeoecology 440, 455–466.
Multi-proxy study of red clays from the Carpathian Basin: implications for provenance, sedimentary processes and age, and late Cenozoic climate and environmental changes
Reddish paleosols are common in Pleistocene loess–paleosol sequences throughout Central and SE Europe and East and Central Asia, as well as throughout the geological record. Thus, color alone may not be diagnostic of paleosol climate. Different data imply a warmer and possibly wetter habitat of open vegetation for the Pliocene in the region compared to that of today. There is a controversy about the age and formation of red clays proper, which are younger than Upper Miocene and superimpose them in the Carpathian Basin. The age of red clays cannot be identified exactly by radiometric and paleomagnetic measurements. This cutting-edge research project will try new methods for the age determination and paleoenvironmental reconstruction of the red clays and paleosols in the Carpathian Basin. Our history is preserved in archives. For climate data, we can even rely on written records from the past 200 years. However, when going back further in time, we need to rely on geological archives.
Kovács, J., Újvári, G., Varga, G., Seelos, K., Szabó, P., Dezső, J. & Gammoudi, N. (2020) Plio-Pleistocene dust traps on paleokarst surfaces: a case study from the Carpathian Basin. Frontiers in Earth Science 8, 189, doi: 10.3389/feart.2020.00189.
Kovács, J., Farics, É., Szabó, P. & Sajó, I. (2020) Fe–Al phosphate microcrystals in pedogenic goethite pisoliths. Minerals 10, 357, doi.org/10.3390/min10040357.
Kovács, J., Raucsik, B., Varga, A., Újvári, G., Varga, Gy. & Ottner, F. (2013) Clay Mineralogy of Red Clay Deposits from the Central Carpathian Basin (Hungary): Implications for Plio/Pleistocene Chemical Weathering and Paleoclimate. Turkish Journal of Earth Sciences 22, 414–426.
Kovács J., Fábián, Sz.Á., Varga, G., Újvári, G., Varga, Gy. & Dezső, J. (2011) Plio-Pleistocene red clay deposits in the Pannonian basin: A review. Quaternary International 240, 35–43.
Pleistocene periglacial environment in the Pannonian Basin
During the Last Glacial Maximum (ca. 26–19 ka BP), the paleoenvironment of Central Europe was dominated by periglacial conditions. The aim of this research is to investigate the Late Pleistocene environmental changes in the Pannonian Basin (mainly related to frost/frozen ground) using multidisciplinary methods, and to place and interpret the results in a Central European context. As a primary environmental indicator, sand-wedge polygons and the sandy infilling material are investigated under field and laboratory conditions. We have now identified polygonal networks over several hundred km2 in the western part of the country using satellite imagery and drone images. During repeated fieldwork, samples from sandy exposures are subjected to various laboratory tests at the university, such as grain size analysis or scanning electron microscopy. Our research covers a wide range of earth science disciplines (geoinformatics, sedimentary geology, geomorphology), combining modern field and laboratory tools with a cutting-edge topic.
Fábián, S. Á., Kovács, J., Varga, G., Sipos, G., Horváth, Z., Thamó-Bozsó, E., & Tóth, G. (2014). Distribution of relict permafrost features in the Pannonian Basin, Hungary. Boreas, 43(3), 722–732. https://doi.org/10.1111/bor.12046
Kovács, J., Fábián, S. Á., Schweitzer, F., & Varga, G. (2007). A relict sand-wedge polygon site in north-central Hungary. Permafrost and Periglacial Processes, 18(4), 379–384. https://doi.org/10.1002/ppp.600