Presence of Bentonite beds in the earliest Eocene Tienen Formation in Belgium as evidenced by clay mineralogical analyses

In the Tienen Formation of earliest Eocene age in Belgium, at the southern rim of the North Sea Basin, the presence of thin bentonite and bentonitic layers has been identified and confirmed by XRD, ESEM and major element chemical analyses. For the first time in Belgium, bentonites have been described at that stratigraphic level, linking it to the well known earliest Eocene North Sea Basin volcanism related to the onset of the NE Atlantic Ocean opening between Greenland and Europe.