Paleogeographic and -environmental evolution of the Early Permian Tambach Basin

The Bromacker Project investigates the “Ursaurier” vertebrate lagerstätte of the same name in Early Permian redbeds of the Tambach Formation. Its geologic-paleontologic subproject aims to contribute key parameters such as paleoecology, -climate, -geography, and depositional environments to the reconstruction of the Tambach Basin. Two new, fully cored research boreholes, combined with facies-oriented geologic mapping, the analysis of legacy cores, large-scale outcrop 3-D documentation and -interpretation utilizing UAVs, as well as paleocurrent analysis and sandstone petrography allowed detailed insights in the paleogeography, depositional environments and paleoecology.

The basal Bielstein Conglomerate Member was deposited on a fluvial braidplain, sourced from the deeply dissected Oberhof Porphyry Complex (OPC) to the east. Transport occurred towards the west-southwest, beyond the limits of the current Tambach Basin area. The transition into the Tambach Sandstone Member is gradual in the southern part of the basin with little changes in provenance and fluvial style, suggesting the continued existence of topographic relief within the OPC. In the northern part of the basin, a rapid change towards floodplain deposits, rarely interbedded with OPC-sourced conglomeratic channels and fine-grained sandstones, was sourced from metamorphic rocks to the west and a reduced relief. This trend is terminated by fluvial-fan conglomerates from the northwest which are present throughout the basin and sourced from the Mid German Crystalline High, documenting its uplift

The results show a rather small, dynamic basin dominated by fluvial systems with rapid spatial and temporal changes in depositional environments and numerous habitats for the Bromacker ecosystem populations.