Een vroeg-miocene fauna uit het Zand van Kiel (Formatie van Berchem) bij Post X in Berchem (Antwerpen)

Abstract: An Early Miocene fauna from the Kiel Sand Member (Berchem Formation) at Post X in Berchem (Antwerp). During the summer of 2015, a section of the Berchem Formation (Early-Middle Miocene) could be studied at the temporary construction site of Post X in Berchem (Antwerp, Flemish Region, Belgium). The lithostratigraphy of this outcrop is described. A sharp lithological boundary between the greyish Kiel Sand Member and the overlying blackish, clayey Antwerpen Sand Member was observed. A horizon with vertebrate remains (layer 2 in the description) 50 cm below the top of the Kiel Member was intensively sampled for macro fossils. The horizon consisted of small accumulations of heavier material (e.g. pieces of sandstone, phosphatic concretions, fossils) and is the result of mechanical sorting, probably by storm related winnowing. A first inventory shows a rich elasmobranch fauna (at least 31 species) dominated by benthic species: Rajidae, Dasyatidae and Squatina. Less frequent benthopelagic taxa are present: Squalus, Notorynchus, Carcharias, Carcharhinus and Physogaleus. With the exception of the genus Isurus, teeth of pelagic taxa such as Alopias and Keasius are much less represented. Skeletal elements of bony fish (Teleostei) are abundant. In the otolith fauna, Colliolus is dominant. Some cetacean remains (Eurhinodelphinidae, Kentriodontidae, Physeteroidea), bones of bird (Procellariiformes), decalcified molluscs (Cordiopsis, Glycymeris) and other invertebrate fossils are also reported. Remarkable is the discovery of a piece of driftwood (Taxodioxylon sp.). The purpose of this article is to characterize depositional environments and give a first overview of the faunas of the poorly known Kiel Sand Member in the area of its stratotype.