A review of the lower and middle Miocene of northern Belgium

1. Introduction The North Sea was a semi-enclosed basin during the Neogene. The marine connection between the southern North Sea Basin and the Channel was prevented by the Weald-Artois ridge, while in the north an open marine connection with the Norwegian-Greenland Sea existed (Ziegler, 1990; Rasmussen et al., 2008; Rasmussen et al., 2010). Tectonic uplift of northern Belgium during late Oligocene time pushed the southern coastline of the North Sea northwards, and late Oligocene sedimentation in Belgium was limited to a thin cover of glauconitic sand in northern Belgium; it is only well developed in the subsiding Roer Valley Graben (RVG) in the very northeast (Dusar et al., 2020, this volume). At the beginning of the Miocene, during the global sea-level rise after the Mi1 glacial maximum (Miller et al., 1991), sea levels rose and northern Belgium was invaded by a marine transgression from a northern to northwestern direction (Louwye, 2005). Furthermore, Munsterman & Deckers (2020, this volume) recorded in two wells in the northeastern part of the Campine latest Oligocene – earliest Miocene (Aquitanian – early Burdigalian) deposits and proposed a transgressive phase from the Roer Valley Graben towards the Campine area. The marine and continental lower and middle Miocene deposits are restricted to northern Belgium and crop out in the vicinity of the city of Antwerp (Fig. 1). In the Campine area, east of Antwerp, lower and middle Miocene sediments are present in the subsurface