GFÚ researchers, Lotta Ylä-Mella and Kaleb Wagner, sampled ancient glacial deposits at field sites stretching from Denmark to Lithuania this summer as part of their GAČR-funded PhD projects. Members of the Surface Processes & Paleoclimate team completed the first fieldwork season of a project that seeks to determine when the great Eurasian ice sheets first expanded from Scandinavia into the European Plain – potentially as early as a few million years ago.
Left: Collecting samples of glacial sediment. From left-right: Kaleb Wagner, Albertas Bitinas. Right: Researchers examining archived sediment cores at the core repository of the Lithuanian Geological Survey. From left-right: Vaida Šerienė, Albertas Bitinas, Lotta Ylä-Mella
The GFÚ group is collaborating with international researchers to identify over a dozen field sites containing ancient glacial sediments. Samples of buried Scandinavian rocks were collected and are now being analyzed by Lotta Ylä-Mella and Kaleb Wagner at the Aarhus University Cosmogenic Nuclide Laboratory to measure their unique concentrations of rare radiogenic isotopes. These cosmogenic nuclides (beryllium-10 and aluminum-26) were produced via cosmic ray bombardment while the rocks were exposed at the surface before being plucked from the Baltic Shield and transported southward by ice sheets into the low-lying European Plain. Once buried, nuclides in these rocks decay at a differential rate, which can be modeled numerically to estimate their depositional age. Together with international collaborators (DK, USA), the SPP team aims to develop new quantitative ages for the oldest terrestrial records of continental glaciation in Europe, allowing comparison with marine palaeoclimate archives.
Through regional correlation, the researchers hope to better understand what drove the advent of the great Northern Hemisphere ice sheets.
Left: Researchers discussing glacial deposits at a quarry site in eastern Germany. From left-right: John Jansen, Kaleb Wagner, Stefan Wansa, Henrik Rother, Shantamoy Guha. Right: Examining the lithological composition of gravel in till at a natural exposure in southeastern Poland. Izabella Szuman-Kalita and Jan Dzierżek in background. Bottom: Lotta Ylä-Mella observing a coastal-cliff exposure in northern Jutland, Denmark.
In addition to internal funding support from GFÚ, this is funded by the Czech Science Foundation (project #22-13190S) and the Granting Agency of Charles University.
John Jansen, Lotta Ylä-Mella, Kaleb Wagner