Pleistocene terraces of the Vltava River in the Budějovice basin (Southern Bohemian Massif): New insights into sedimentary history constrained by luminescence data

We studied Quaternary sediments from the Budějovice basin in southern Bohemia, now being able to reconstruct the landscape formation of this area during the late Pleistocene. The main objective of this study was to map fluvial terraces of the rivers Vltava and Mal¨e in the basin and to constrain their ages by luminescence dating. Topographic data from a high-resolution DEM in combination with lithological profiles of more than 1000 boreholes allowed identifying five terrace levels (BB 1 to BB 5) with bases ranging from 7 m below to 26 m above the recent mean water level of the Vltava River. For the lowermost terrace level BB 1, a consistent stratigraphy with ages ranging between 84.5±9.0 ka and 7.9±0.8 ka was constrained. Additionally, we obtained luminescence ages of alluvial fan and colluvial deposits, which allow us to better constrain the late Pleistocene sedimentation history of the study area. Based on the spatial distribution of derived ages, the terrace level BB 1 represents a complex sediment body incorporating more distinct packages of river aggradation. The presence of stacked fluvial deposits of Pleistocene age underneath the recent floodplain points to an ongoing subsidence or relative tectonic stability of the Budějovice basin during the late Pleistocene.