Opglabbeek Formation

The Opglabbeek Formation is a geologic formation in the subsurface of the eastern part of Belgian Limburg. The formation consists of lagoonal and fluvial clay and sand and was deposited during the early Selandian (Middle Paleocene, about 60 million years old). The formation is named after the town of Opglabbeek in Limburg.

The Opglabbeek Formation is subdivided into two members: the Opoeteren Member (red clay with layers of lignite) and the Eisden Member (fine sand with crags). Some authors describe a third member: the Maasmechelen Member, but this is alternatively seen as part of the Eisden Member.

The Opglabbeek Formation has a thickness between 20 and 60 meters. It lies stratigraphically on top of the Houthem Formation (early Paleocene calcareous sandstone). On top of it lies the Heers Formation (Middle Paleocene sands and marls). The Opglabbeek Formation is divided into the Hesbaye Group and can be correlated with parts of the Landen Formation of adjacent areas in the southern Netherlands.