Small mammal assemblages from the Quaternary succession at Moriaanshoofd (Zeeland, the Netherlands) and their significance for correlating the Oosterschelde fauna

We investigated fossil small mammals from a borehole near Moriaanshoofd (Zeeland, southwest Netherlands) in order to get better insights in the fossil mammal faunas that are found in the subsurface in the southwestern Netherlands, and to investigate the age and provenance of the mammal fauna that is being dredged from the deep tidal gullies in the nearby Oosterschelde estuary. The record in the borehole covers Gelasian (Early Pleistocene) to Holocene deposits, represented by six formations. Thirty-nine specimens of small mammals were obtained from the borehole. These fossils derived from the Early Pleistocene marine Maassluis Formation and from directly overlying deposits of a Late Pleistocene age. During Weichselian times (33-24 ka), a proto-Schelde River shaped the northern Oosterschelde area. The river reworked substantial amounts of Early and Middle Pleistocene deposits. At the base of the Schelde-derived fluvial sequence (regionally described as the Koewacht Formation), Gelasian vertebrate faunas were concentrated in the channel lag. The Late Pleistocene channel lag is almost certainly the main source for the rich Early Pleistocene vertebrate faunas with larger mammals dredged from the Oosterschelde.