Multiproxy evidence of middle and Late Pleistocene environmental changes in the loess-paleosol sequence of Buhzdar (Czech Republic)

摘要

Loess-paleosol sequences preserve information that can be used to reconstruct paleoenvironments. A dense network of reliably analyzed sequences from different geographic locations is crucial to address ecological and climatic trends, which occurred during the Pleistocene. This paper focuses on a loess-paleosol sequence in Buhzdar, situated 9 km NW of Prague, Czech Republic. Geochemical approaches (total organic carbon, XRF elemental analyses, XRD mineralogy, C-13 and O-18 stable isotopes) are combined with grain-size distributions and optically stimulated luminescence (OSL) to assess the climatic conditions at the time of formation of the strata. The oldest loess at this location was formed circa 200 ka ago (MIS 7), making it the oldest loess in Central Bohemia for now. The Buhzdar loess-paleosol sequence was highly affected by several erosion events, Eemian paleosols (MIS 5e) being completely missing. The partly relocated paleosols situated at the lower part of the Buhzdar sequence represent a period of increased humidity during late MIS 7 and MIS 6. Despite the fact that the Buhzdar profile is not particularly thick (5 m), significant changes in paleoclimate reconstructions have been detected.