1. INTRODUCTION
The occurrence of Neogene sediments is limited to northern Belgium, i.e., to the provinces of Antwerp, Limburg and the northern part of Brabant and East Flanders. They consist essentially of glauconitic sands with a varying clay admixture and are furthermore characterised by the abundant occurrence of shells, often in massive layers, and local decalcification. Basals gravels are present between the units. Deposition took place in a shallow marine to perimarine environment at the southern margin of the North Sea Basin. An overview of the sequence stratigraphy, biostratigraphy and geometrical relationships of the Belgian Neogene units is given by Vandenberghe et al. (1998). The Neogene of Belgium is lithostratigraphically divided into 9 formations. Three formations (Berchem Fm, Diest Fm and Bolderberg Fm.) are placed in the Miocene, six in the Pliocene (Kattendijk Fm, Kasterlee Fm, Lillo Fm, Mol Fm, Poederlee Fm and Kiezeloöliet Fm). No groups are defined. A subdivsion of the formations into members or layers is given. The occurrences of the neogene formations are illustrated in Figs. 1, 2 and 3.
Figure 1: occurrence of the paleogene and neogene formations along a transect from the French - Belgian border to Woensdrecht.
Figure 2: occurrence of the paleogene and neogene formations along a transect from Kallo to the Maas river.
Figure 3: occurrence of the paleogene and neogene formations along a transect from Oostende to the Maas river.