The Brussel Formation (Dutch : Formatie van Brussel ; French : Formation de Bruxelles ; abbreviation: Br) is a geologic formation in the subsurface of central Belgium . The formation is named after the Belgian capital, Brussels . It consists of shallow marine sandstone and calcareous sands, deposited in the sea that covered Belgium 45 million years ago, in the Eocene .
The Brussel Formation crops out in Walloon Brabant and the north of the provinces of Namur and Hainaut . It is normally about 30 metres in thickness. In Flemish Brabant and Antwerp the formation can be found in the subsurface.
The Brussel Formation is subdivided into five members : the Archennes Member (conglomerates ), the Bois de la Houssière Member (quartzites ), the Chaumont-Gistoux Member (glauconiferous quartzites), the Diegem Member (glauconiferous quartzite) and the Neerijse Member (glauconiferous calcareous sand). The formation consists either of cross-bedded non-calcareous sands alternating with thin beds of marl and clay or calcareous fine sands with traces of bioturbation .
The formation was formed during the early Lutetian age (about 46 million years ago) and is part of the Zenne Group . Stratigraphically on top of the Brussel Formation is the Lede Formation (also part of the Zenne Group), or when this formation is absent the Maldegem Formation (Bartonian ) or Tongeren Group (Priabonian to Rupelian ). The Brussel Formation is normally lying stratigraphically on top of the Aalter Formation (part of the Zenne Group) or deposits of the Ieper Group .
See also
References
Bibliography
Laga, P.; Louwye, S. & Geets, S. (eds.); 2001: Paleogene and Neogene lithostratigraphic units (Belgium) , Geologica Belgica 4(1-2), p. 135-152
