The Lower Permian Bromacker locality preserves what may legitimately be argued as the most well-preserved terrestrial vertebrate tetrapods of their age in the world. It is within outcrops of the Tambach Formation in the midregion of the Thuringian Forest, approximately 1.5 km north of the village of Tambach-Dietharz and 20 km south of the town of Gotha in formerly eastern, now central, Germany. Over fifty years of excavation, sedimentological and paleoecological research have demonstrated the Bromacker to be an internally drained paleograben showing evidence of being the earliest modern type terrestrial foodweb, predating those of the Mesozoic by minimally 50 million years or more. The locality has been mined intermittently for sandstone for over 150 years, and became initially famous for its preservation of footprints, first studied by Wilhelm Pabst from 1887-1908. In 1974 Thomas Martens discovered the first vertebrate skeletal fossils, and continued to work the quarry from 1975-1992, and in 1993, Martens initiated a remarkable international collaborative effort. The Bromacker is significant in its collaborative and cooperative approaches in almost all aspects, from research, to funding, to outreach, to dissemination. Initially teams from the United States joined Martens and his German crews; later to be joined by colleagues from Slovakia, Canada, and the United Kingdom. Likewise, funding came from German and American institutions, as well as National Geographic and NATO. Education, scientific communication, and outreach have ranged from academic publications to interpretive multilingual signage to popular media to cooperative support from the surrounding villages, businesses, and cities.

The BMBF-funded BROMACKER project (2020-2025) uniquely combines multidisciplinary research on the early Permian Fossillagerstätte Bromacker in the Thuringian Tambach Basin and UNESCO Geopark with innovative, experimental and multimedia science communication formats, involving the general public with novel and interactive formats. The site provides an exceptional window into the evolution of early terrestrial vertebrates and their ecosystems, preserving extraordinary fossils of tracks, traces, burrows and body fossils primarily of vertebrates in Lagerstätten-quality. Spectacular vertebrate fossils display distinct autecological specializations such as herbivory, bipedality and fossoriality. Another unique selling point is the earliest evidence of the modern trophic pyramid in terrestrial vertebrate ecosystems. The 2020-2025 project further revealed the earliest body impressions and evidence of epidermal scales and aggregation behavior in synapsids as well as the earliest occurrence of complex vertebrate burrows. The natural science research is accompanied by diverse and cutting-edge science communication formats, including special exhibitions, social media, podcasts, 360° projections, interactive websites, school projects, as well as in-person and live virtual public tours and events at the excavation site, in the partner institutions and external venues. This multidisciplinary and interactive approach of communicating scientific processes and results to the general public successfully increases the understanding and acceptance of geoscientific research in general. Visitor numbers at the excavations and in the entire region also increased, reflecting the importance of Bromacker research and outreach for tourism and networking with enormous potential for the future.

The UNESCO Global Geoparks were established in 2015 and developed alongside a corresponding increase in the demand for geotourism. The UGGps are also developing their own strategies to enhance environmental education and to actively improve the economic and social conditions of the regions where they are located. Despite this, the lack of dedicated personnel and projects to evaluate the Geoparks' impact represents a challenge for all Geoparks worldwide.

To address this challenge, the UGGp Thuringia Inselsberg Drei Gleichen has already developed several surveys to improve its offerings. For example, the Bromacker fossil site, despite its scientific importance, accessibility, and central role in obtaining UNESCO Geopark recognition, was found to be almost unknown among locals and tourists in the region. By leveraging the potential of the Bromacker and other Geopark-related projects, interviews and surveys with citizens and tour operators were carried out and evaluated. Furthermore, the opinions of companies cooperating with the Geopark were included. Among the preliminary results, the interviews with companies highlighted the Geopark-related project as a significant economic opportunity, and the visibility of the Bromacker fossil site has increased dramatically.

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.

We investigate trace fossils and bioturbation degree of two sediment cores extracted from the Tambach Formation and from excavations at the Bromacker locality.

The degree of bioturbation of the investigated silt- and sandstones is rather low in most parts of the sections, averaging at about 8%. Thus, the low degree of bioturbation varies between grade 0 and 2 following the classification of Reineck (1963). Most frequent structures are burrows of 2-38 mm diameter. In general, the dominating small burrows of <5 mm penetrate the bedding planes perpendicular or with a steep angle (Skolithos), whereas larger burrows of a few cm in diameter are mostly horizontal. Burrows are simple, unbranching and show no internal or surface structures. They are characterized by passive infill, similar to (Palaeophycus) or slightly different from the host rock (Planolites).

Some additional trace fossils are preserved as convex hyporeliefs on sandstone slabs. Most abundant is Tambia spiralis (Müller, 1956), which was selected by Paläontologische Gesellschaft as Fossil of the Year in 2024. This trace fossil is characteristic of the Tambach Formation and geographically and stratigraphically almost restricted to it. Less common is the feeding trace fossil Striatichnium bromackerense Martens, 1982. Very rare are trackways and trails of Arthropoda, such as Diplichnites, Diplopodichnus and Lithographus.

The investigated sediments were deposited as fluvial overbank and channel sediments with short transport routes as low rounding degree of grains indicates. Degree and type of bioturbation point to a Scoyenia ichnofacies with strong seasonal effects under a wet-and-dry tropical climate.