Das Projekt "Palaeogeographic ralationships of Early Carboniferous ammonoid assemblages in North America" wird vom Umweltbundesamt gefördert und von Museum für Naturkunde der Humboldt-Universität zu Berlin, Institut für Palöontologie durchgeführt. The Early Carboniferous (Mississippian) is a time that is characterised by significant changes in the configuration of the main tectonic plates. The Variscan Orogeny led to the separation of shelves and subsequent provincialism of ammonoid communities. Therefore, a Subvariscan Realm (Northwestern and Central Europe) of can clearly be distinguished from a Prototethian Realm (South Europe, North Africa, South Urals). Faunal provinces in North America, however, are much less well investigated. Within the proposed project, a comparison of the assemblages present in the Ouchita Foreland Basin of the American Midcontinent (Arkansas, Oklahoma, Texas) with the Antler Foreland Basin of the Western United States (California, Nevada, Utah) will be carried out. The ammonoid faunas of these two areas will be investigated in a global context. The goal of the project is the quantitative analysis of the biogeographic patterns and the timing of the mid-Carboniferous adaptive radiation of the ammonoids.