Observations on the Pliocene sediments exposed at Antwerp International Airport (northern Belgium) constrain the stratigraphic position of the Broechem fauna

1. Introduction The Antwerp harbour region (Belgium) is well known for its thick and fossil-rich Pliocene successions (e.g. Vervoenen, 1995; Marquet, 1998, 2002, 2004, 2005; Marquet et al., 2009; Duboys de Lavigerie et al., 2020; Tsai et al., 2020). To the east these units become thin and discontinuous and often are affected by decalcification and reworking and the stratigraphic subdivision is not well understood (Marquet, 1980; Bisconti & Bosselaers, 2020; Bosselaers et al., 2004). To the southeast of Antwerp a Pliocene fauna has been documented that has a specific taphonomic character and species composition (Marquet, 1980; Wesselingh in van Bakel et al., 2003). This so-called Broechem fauna is found in brown-reddish spherical sandstone nodules of up to circa 15 cm long, and is dominated by single and paired specimens of a number of large bivalve species, partially as moulds, including Cyrtodaria angusta, Arctica islandica, Acanthocardia aff. aculeata, Cardiidae indet. (sensu Wesselingh in van Bakel et al., 2003) and Callista chione. The presence of Pygocardia rustica forma tumida implies an Early Pliocene age (Marquet, 1980; Wesselingh in van Bakel et al., 2003; Bosch & Wesselingh, 2006). Marquet (1980) reported the Broechem fauna mostly ex situ from a gravel interval supposedly attributed to the Kattendijk Formation overlying upper Miocene Diest Formation deposits at temporary outcrops for the construction of a water basin between the villages of Broechem and Oelegem. How