Geodynamic and tectonic context of Early Cretaceous Iguanodon-bearing deposits in the Mons Basin

The Wealden facies sediments of the Mons Basin, where the Bernissart Iguanodons were discovered, are affected by multiple tectonic features. Different systems of faulting and fracturing are observed in terms of type, orientation, movements, and dating: reverse and normal faults, strike-slip fault and joints. The synsedimentary character of the deformation is particular clear in the clayey sediments of the Early Cretaceous Hautrage Clays Formation. The local interaction between tectonic and karstic phenomena discussed here contribute to the trapping and the conservation of the Wealden fossil-rich deposits in a floodplain depositional environment confined on the northern flank of the future Mons Basin. In this area, Lower Cretaceous sediments also recorded several younger tectonic phases, because of the proximal influences of regional crustal zones, like inversion tectonic at the end of the Cretaceous and extensional regime linked to the dynamic of the lower Rhine Graben Embayement.