Titel: Aeolianites of the Detfurth Formation (Middle Buntsandstein, Lower Triassic) in the Hessian Depression: spatial distribution and stratigraphic affiliation with regard to modern stratigraphic concepts and use in applied geosciences
Hessian Agency for Nature Conservation, Environment and Geology (State Geological Survey), Germany
Veranstaltung: GeoKarlsruhe 2021
This talk focusses on the Detfurth Formation of the Hessian Depression and aims to point out a modern way of subdividing the sedimentary record, serving as a profound basis in applied geoscientific disciplines such as geothermal exploration, hydrogeology, or 3D modelling. Particular attention is paid to aeolian sediments, as they have different rock properties compared to fluvial sediments.
Aeolian sediments are widespread along the western margin of the Hessian Depression, locally building up the entire Detfurth Formation. Towards the central Hessian Depression, they interfinger with aquatically deposited sediments of the Detfurth Formation, yet are widely traceable in its lower part. Interestingly, similar aeolianites regionally also occur above the Detfurth Claystone unit, and then usually were assigned to the Hardegsen Formation, following the fining-upward principle of the Buntsandstein “Folgen” – with some doubts remaining (Dersch-Hansmann et al. 2013, SDGG).
Based on detailed sedimentological recordings of core drillings, a facies model of aeolian and alluvial sand plains, braided rivers, deltas, and the central playa lake system is proposed (Hug-Diegel 2021, ZDGG). The correlation scheme also illustrates that spatial relationships of the Detfurth subformations in the Hessian Depression clearly deviate from a “layer-cake geometry”. For geogenetic reasons and due to their special rock properties, the aeolianites should be combined in a separate subformation, but assigned to the Detfurth Formation. This is consistent with the idea of a dual subdivision of the Buntsandstein into both regional geochronologic units (allostratigraphic “Folgen”; Lutz et al. 2005, Newsl. Strat.) and – independent – lithofacies-stratigraphic units (formations).
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