Long-term terrestrial records of the Middle Danubian Basin

Abstract

In eastern central Europe, in the Middle Danube Basin, loess and loess-like deposits cover various morphotectonic levels in a total area of ca. 150,000 km 2. Basin types of various elevations and sizes are predominant. Under different geomorphological or morphotectonic conditions — over an identical time interval — the variation in the rate of basin subsidence produces various litho- and chronostratigraphical sequences. The subaerial sequence of basins affected by prolonged subsidence in the Quaternary is subdivided by paleosols of larger number than the loess-paleosol sequence of basins, elevated plateaus or watersheds which underwent more moderate subsidence during the Quaternary. Loess-paleosol-sand sequences on pediments (100–150 m above sea level). In the loess-paleosol-sand sequences of 50–100 m thickness, ca. 12 loess, 10 sand and silt layers and 20–30 paleosols are present. The age of these profiles with hiatuses, is Pliocene-Pleistocene. Loess-paleosol-sand sequences on alluvial fans and terraces (10–100 m relative heights). The loess sequence is 40–60 m thick and subdivided by 10–12 loess horizons, 10–12 paleosols and 5 or 6 sand layers. LTR — Pliocene-Pleistocene. Subaerial basin sediment locally of 500–1500 m thickness. The surface of the basin is a flood plain at 90–100 m above sea level. In the basin sediments the number of paleosols may reach one hundred. In several boreholes there are 6–12 red soils or red clays between 600 and 1000 m. 12–16 intercalated sand layers are observed. The age of this almost complete sequence is 5.2–5.4 Ma BP. In the most intensively subsiding basins sedimentation was almost continuous; during the Pliocene ca. 50–60 and in the Pleistocene ca. 50 soils developed. In contrast on the non-subsiding foothills only 20–30 soils formed during the Pliocene and Pleistocene and several gaps are detected in the sequence.