Age, composition and spatial distribution of sandy loess in north-eastern Germany (Fläming, Brandenburg)

Abstract

The sandy loess deposits in the lowlands of northern Germany present a valuable sedimentary archive for late Weichselian periglacial geomorphodynamics. While other aeolian sediments from the Late Quaternary, especially loess deposits and sand dunes, have been studied and dated in some detail in the last decades, sandy loess has received less scientific attention with respect to its genesis, composition, age and provenance as well as distribution patterns. In this study, we present detailed results for three sediment sections located on the Fläming ridge in the south of the state of Brandenburg. According to our results from luminescence dating, the sandy loess deposits of this area were deposited during the late MIS 2 (19–14 ka) with a highly variable thickness of at least up to 4 m, followed by a deposition of periglacial coversands shortly thereafter. The sandy loess deposits display a homogeneous geochemical composition and grain size characteristics similar to loess sections in the main loess areas to the west and south. Furthermore, we analysed a large dataset of geological drill data and performed a spatial interpolation of sandy loess distribution in the Western Fläming. Despite the strongly dissected modern landscape of the Fläming ridge which is partly the result of intense Holocene soil erosion processes, general patterns of the original loess distribution could be deduced. Based on these findings, we were able to identify the low-lying areas to the north and north-east of the study area to be the most likely source areas for the sandy loess as a result of katabatic winds originating from the Fennoscandian Ice Shield. Thereby, this study yields important insights regarding aeolian transport and deposition patterns under periglacial conditions in the Central European Lowlands.