The largest prehistoric landslide in northwestern Slovakia: Chronological constraints of the Kykula long-runout landslide and related dammed lakes

摘要

This study deals with the chronology of the largest long-runout landslide in the northwesterrn part of the Western Flysch Carpathians (Kysucke Beskydy Mts, Slovakia). Despite the impossibility of using direct radiocarbon dating method, time constraints for the evolution of the landslide were determined on the basis of the dating of various sedimentological/geomorphological elements situated on and adjacent to the landslide body. The results show that the landslide evolved between ～10.3 and 9.0 ka ~(14)C BP, i.e. in the wider transitional phase between the Late Glacial (LG) and the Holocene. The main mass movement activity took place at the turn of the Younger Dryas/Preboreal chronozones, whereas retrogressive activity continued up to the Preboreal/Boreal transition. Radiocarbon dating together with pollen analysis and sedimentology of landslide-dammed palaeolakes and colluvial peat bogs revealed almost continuous Holocene palaeogeo-graphical records between ～ 10.3 and 3.3 ka ~(14)C BP. Periods of enhanced sediment supply to the reservoirs in ～9.9-9.0, ～8.4-8.2, ～6.9-6.5 and ～4.5 ka ~(14)C BP correlate well with palaeogeomorphic and palaeohy-drological records from nearby Polish Carpathians. The study confirms that the LG/Holocene transition represented a favourable period for the evolution of large landslides not only in glaciated high mountain areas, but also in medium-high mountains of Central Europe.