Reconstructing Late Glacial–Early Holocene dune formation and wildfire dynamics using radiocarbon and OSL dating: Łaskarzew, Poland

The chronology of Late Glacial and Early Holocene dune formation and wildfire activity at the Łaskarzew site, eastern Poland, was established using AMS radiocarbon (¹⁴C) and optically stimulated luminescence (OSL) dating. Situated within the European Sand Belt, the profile preserves 13 aeolian-soil cycles characterised by alternating phases of aeolian deposition, soil formation, and wildfire episodes, demonstrating the dynamic response of aeolian systems to short-term climatic oscillations. A total of 26 charcoal samples, collected from palaeosols and charcoal layers, were radiocarbon-dated, and cross-referenced with OSL ages of quartz grains, resulting in a robust chronological framework. Dune formation began during the Oldest Dryas, with intensified aeolian activity and four wildfire events recorded during the Allerød interstadial, a period marked by rapid vegetation regeneration and recurring fire episodes. The absence of Younger Dryas sediments reflects extreme environmental conditions, including aridity, limited vegetation, and intensified aeolian erosion. The Holocene sequence, enriched with charcoal-rich deposits, records nine independent wildfire episodes over approximately 4500 years, linked to warm climatic conditions that favoured the expansion of fire-prone pine forests and shaped dune environments. Aeolian activity persisted through this period, accumulating approximately three metres of sediment, before ceasing around 7 ka BP as vegetation stabilised the landscape. The integration of radiocarbon and luminescence dating techniques provided a detailed Late Quaternary chronology, offering valuable insights into the interplay of fire, vegetation, and aeolian processes within the European Sand Belt.