The stratigraphic position of the Cambrian Jodoigne Formation redefined (Brabant massif, Belgium)
Département des Sciences de la Terre et de l’Environnement, Université Libre de Bruxelles, Avenue F. Roosevelt 50 CP 160/02, B-1050 Brussel, E-mail : herbosch@ulb.ac.be
Research Unit Palaeontology, Geology & Pedology, Universiteit Gent, Krijgslaan 281, S8, B-9000 Gent, E-mail : Timothy.Debacker@UGent.be
Geological Survey of Belgium, Jennerstraat 13, B-1000 Brussel, E-mail: Kris.Piessens@naturalsciences.be
Abstract
Abstract. Until now, the stratigraphic position of the Cambrian Jodoigne Formation was very poorly constrained. On the basis of detailed mapping, lithological and sedimentological observations, structural field work and magnetic studies in the type area of the Jodoigne Formation, combined with an evaluation of existing biostratigraphic data, a much better constrained stratigraphic position is proposed.
In the Cambrian stratigraphy presented herein, the Jodoigne Formation is moved from below the basal Cambrian Blanmont Formation up to a position in between the Lower Cambrian to lower Middle Cambrian Oisquercq Formation and the Upper Cambrian Mousty Formation. Hence, a Middle to Upper Cambrian age is suggested. A time-equivalence between the upper parts of the Jodoigne Formation and the lower parts of the Mousty Formation cannot be excluded.
In the type area of the Jodoigne Formation, the proximity with the Blanmont Formation can be explained by means of the Asquempont Detachment System, this being fully compatible with the nature and orientation of this detachment system. In turn, the new stratigraphic position of the Jodoigne Formation results in a better understanding of the orientation and extent of the Asquempont Detachment System, and fully supports the continuation of this detachment system along the N-side of the Brabant Massif.