The upper Miocene Deurne Member of the Diest Formation revisited: unexpected results from the study of a large temporary outcrop near Antwerp International Airport, Belgium

Abstract

A 5.50 m thick interval of fossiliferous intensely bioturbated heterogenous glauconiferous sand of the upper Miocene Diest Formation is documented from a very large temporary outcrop just southeast of Antwerp International Airport (northern Belgium), allowing to observe lateral variations over several hundreds of meters and to collect many vertebrate and invertebrate fossils. This paper documents observations on lithology, sedimentary and post-sedimentary structures, and discusses the results of the multi-proxy analyses of the sediment (granulometry, glauconite content, clay mineralogy, Fe content and Fe3+/Fe2+ ratios), the interpretation of the trace fossil assemblage and the sedimentary structures as well as of the large-scale samplings of micro-, meso- and macrofossils. We evidence that the Diest Formation in the Antwerp area consists of two different lithological entities, and that this twofold character can be extrapolated to all previously recorded Deurne Member outcrops. A revised lithostratigraphic scheme for the Diest Formation in the Antwerp area is proposed, with the new Borsbeek member at the base and a redefined Deurne Member at the top.

First fossil record of Mustelus aff. punctulatus Risso, 1826: new evidence for a smooth-hound shark population in the Late Miocene North Sea Basin

“…Contrary to the comparative table in Hoedemakers & Dufraing (2015), Mustelus specimen IRSNB P 10267 was found in layer 4 (Deurne Member). Additionally, the occurrence of isolated Mustelus teeth in the underlying Borsbeek member (layer 5b) was reported by Goolaerts et al (2020) and Mollen (pers. comm, 2021).…”

“…The dinoflagellate cyst assemblages of both the Borsbeek and Deurne members indicate a middle Tortonian age, as the Amiculosphaera umbraculum zone of Dybkjaer & Piasecki (2010) and the DN8 zone of de Verteuil & Norris (1996) were recognized (Louwye, 2002;Goolaerts et al, 2020). Hooyberghs & Moorkens (2005) came to a similar conclusion for the Deurne Member, based on foraminifera.…”

“…This locally resulted in high concentrations of chondrichthyan and teleostean remains, including the studied Mustelus teeth. Notable amounts of these fossils might in fact be reworked from the underlying sediments: the elasmobranch fauna in the basal gravel (31 species) is much more diversified than the poor fauna (9 species) scattered throughout the overlying foresets (Hoedemakers & Dufraing, 2015;Goolaerts et al, 2020). Contrary to the comparative table in Hoedemakers & Dufraing (2015), Mustelus specimen IRSNB P 10267 was found in layer 4 (Deurne Member).…”

“…1; DOV TO_20140101C) presented the opportunity to sample an extensive stratigraphic succession covering a broad age range of sediments from the Miocene Berchem and Diest formations up to the Quaternary. The stratigraphy of this large temporary outcrop was studied in detail by Goolaerts et al (2020) and Wesselingh et al (2020).…”

“…1). A tunnel was excavated, allowing in situ sampling of an extensive Neogene succession, dominated by the Tortonian Diest Formation (Goolaerts et al, 2020). Especially the highly fossiliferous basal gravel of its upper unit, the Deurne Member, could be sampled in detail.…”