Detailed observations at a large temporary outcrop south of Antwerp International Airport (northern Belgium) reveal the complexity of a thin interval of fossil-rich Pliocene sediments found on top of the upper Miocene Diest Formation. Based on the lithological characteristics and mollusc faunas, several units were tentatively attributed to the Kattendijk Formation and the Luchtbal and Oorderen Members of the I,illo Formation. Concretions containing characteristic preserved molluscs dominated by large paired bivalves and that are informally known as the Broechem nodules were observed in situ between the Kattendijk Formation and Lillo Formation, and in reworked position in the base of the latter, indicating a late Early Pliocene age. The role of extensive reworking in the formation of Pliocene units is shown and implications for stratigraphic framework of Pliocene deposits from northern Belgium are discussed.