Sedimentary evidence of landscape and climate history since the end of MIS 3 in the Krkonoše Mountains, Czech Republic

• Published in: Quaternary science reviews 2010-04, Vol.29 (7), p.913-927
• Main Authors: Engel, Zbyněk, Nývlt, Daniel, Křížek, Marek, Treml, Václav, Jankovská, Vlasta, Lisá, Lenka
• Format: Article
• Language: English
• ISSN: 0277-3791; 1873-457X
• DOI: 10.1016/j.quascirev.2009.12.008

A sedimentary core recovered from the cirque basin of Labský důl valley (1039 m a.s.l.) in the Krkonoše Mountains reflects the environmental history for approximately the last 30,000 years. Analyses of magnetic susceptibility, carbon content, pollen assemblages and macrofossil data in a 15 m thick sediment sequence provide the first continuous record of Lateglacial and Holocene vegetation history in Sudetes region of the Czech Republic. The succession of sedimentary units in the lower part of the core suggests that the cirque was ice-free before the onset of the last glaciation at the beginning of marine isotope stage 2. Highly variable climate prevailed during this period with cold conditions culminating about 18 cal ka BP. Cold climates persisted until the Lateglacial period, evidenced by an identified warming and subsequent cooling event correlated with the Younger Dryas period. Sparse, treeless vegetation dominated in the catchment area at that time. The sequence of interrupted thinly laminated silts reflects the retreat and temporary readvance of a local glacier in the cirque during 12.5–10.8 cal ka BP. Subsequently, the alpine treeline ecotone gradually shifted above the cirque floor. Palaeoclimatic conditions in the early Holocene fluctuated strongly, whereas since 5.1 cal ka BP conditions have been more stable. Pollen-based climate reconstructions suggest significant cooling at around 9.8–9.3, 7.7–7.5 and 4.0–3.3 cal ka BP. Spruce forests have dominated the site since 5.0 cal ka BP when the vegetation became similar to the modern one. Two phases of increased sedimentation were identified within the Holocene culminating about 9.2–7.5 cal ka BP and 5.8–5.5 cal ka BP. Sediment yield was as high as 2.4 mm yr −1 during the period, reflecting environmental changes during the Atlantic/Sub-Boreal transition.