Upper Ordovician conodonts kom Bornholm and possible migration routes in the Palaeotethys Ocean

Abstract

Upper Ordovician conodonts from the Dicellograptus Shale Formation on Bornholm are recorded from the base of the Pleurograptus linearis graptolite Zone in the Vasegaardian Stage of the Harjuan Series (Upper Ordovician in Baltoscandic chronostratigraphy). The conodont fauna includes Hamarodus europaeus, Protopanderodus liripipus, Scabbardella altipes and Periodon grundis. Additional uncommonly encountered elements are referred to Eocamiodus gracilis?, Coelocerodontus? sp. A, new genus A sp. A and gen. indet. et sp. indet. The fauna1 composition is indicative of cool deep water to temperate shallow open marine conditions. The Hamarodus conodont fauna of the Pleurograptus linearis graptolite Zone is separated from the Dicellograptus clingani graptolite Zone by a hiatus. This hiatus is recognised along the north-western margins of the Baltica, Avalonia and Gondwana palaeocontinents and it is called the Viru-Harju regressive event (VHRE).