The Lower Danube Loess, New Age Constraints from Luminescence Dating, Magnetic Proxies and Isochronous Tephra Markers

Abstract

Loess and loess-derivative deposits currently form some of the most ubiquitous sedimentary landforms in Europe, including important parts of Romania. Loess-palaeosol sequences (LPS) are continental archives of Quaternary paleoclimates since these deposits are a direct product of geomorphic processes driven by past climate variability. Understanding these processes needs data input provided by absolute chronologies. Loess is generally considered an ideal material for the application of luminescence dating. In this chapter, we present a review of the latest methodological advances in constraining the chronology of several key Romanian LPS alongside the dating of several loess-alluvial deposits that harbour tephra layers. Luminescence chronologies as well as time-depth models based on magnetic susceptibility variations assign the topmost loess layer to the last glacial cycle that comprises, according to the north European stratigraphic terminology, the Weichselian glaciation (Marine Isotope Stage (MIS) 4 and MIS 2 phases). The uppermost palaeosol is assigned to MIS5 especially to the Eemian interglacial (MIS5e), an equivalent to the north European stratigraphy, and to the Riss–Wurm interglacial in the Alpine stratigraphy. As proved by the high-resolution chronologies, the sedimentation rates of loess varied during the last glacial both within a specific loess section, as well as between different loess sections, the major controlling factor being the topographic context. The luminescence chronologies discussed here improved and expanded the long-held stratigraphy of Romanian loess constructed decades ago by using relative methods, suggesting that a re-evaluation of the regional chronostratigraphic inferences in a high-resolution absolute dating approach has to be conducted.