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Stratigraphic architecture and facies development of a fluvial to marine palaeovalley fill from the Saxonian Cretaceous Basin (Lower Cenomanian–lowermost Turonian, eastern Germany)

Integrated stratigraphic-sedimentological analyses of numerous Lower Cenomanian–lowermost Turonian core sections from the Upper Cretaceous Elbtal Group, conducted in the framework of a multilateral research project initiated by the Saxon State-Office for Environment, Agriculture and Geology (LfULG), provide insight into the stratigraphic architecture of the fluvial to marine strata filling an asymmetrical palaeovalley. The project supports the scientific monitoring of the flooding process of the former Königstein uranium ore mine. Our sedimentological-stratigraphical study forms the basis for the hydro-geochemical sampling and analytical strategies of allied project partners.

The N–S-directed Königstein palaeovalley, cut into the basement of the Mid-European Island, borders the Saxonian Cretaceous Basin in the SW. Sedimentation closely followed contemporaneous sea-level changes, reflecting a continuous up-dip shift of facies belts. Northern and middle segments of the palaeovalley were filled with Lower Cenomanian siliciclastic fluvial deposits (Niederschöna Formation), while southern parts were still bypassed. Stratal architectures indicate a steep eastern and a shallower western palaeovalley margin. First marine influences (ichnofossils) are observed in the Middle Cenomanian Wurmsandstein of the upper Niederschöna Formation. The retrogradational facies development continued during the early Late Cenomanian when widespread, mature sandstones (Oberhäslich Formation) draped most of the pre-existing palaeo-topography. After the levelling of the pre-Cenomanian relief by the Niederschöna and Oberhäslich formations, the marine onlap was completed by the rapid plenus transgression and the deposition of the fine-grained offshore deposits of the uppermost Cenomanian Pennrich Formation, culminating in a maximum-flooding interval (Lohmgrund Horizon) at the base of the Lower Turonian Brießnitz Formation.

Details

Author
Melanie Melchisedech1, Birgit Niebuhr1, Markus Wilmsen1
Institutionen
1Senckenberg Naturhistorische Sammlungen Dresden, Germany
Veranstaltung
GeoSaxonia 2024
Datum
2024
DOI
10.48380/aa8t-jq27