Description:
<jats:p>During excavation works for the construction of the TGV track along the motorway Brussels-Liège (E40) near the interchange Tienen-Hoegaarden-Jodoigne a number of interesting, but only temporary outcrops were created. These outcrops offered not only the occasion to learn more about the stratigraphy, paleogeography and paleobotany of the Paleogene, but also revealed some particular deformation features.
The Outgaarden Section, SE of the interchange, showed chaotically deformed sands at the base of the Upper Paleocene Tienen Formation. The highly viscous deformation features originated in a high-energy depositional environment. Dewatering, mass movements and strong currents caused the syndepositional, probably gravitationally-induced sediment deformation.
The Goudberg Section, NW of the interchange, exposed the Overlaar Petrified Forest, of which part of the silicified tree-stumps were recovered to constitute the main feature of the planned GEOPARK HOEGAARDEN. In this section tectonically-induced faulting could be demonstrated. The fault shows a clear normal displacement. A sinistral strike-slip displacement is moreover supposed. Faulting occurred prior to the deposition of the Pleistocene loam cover but definitively postdates the deposition of the Ypresian clays. It is proposed that this faulting event in the Tertiary sediments may be caused by a reactivation of underlying master faults in the Lower Paleozoic basement of the Brabant Massif.</jats:p>