DI-UMONS : Dépôt institutionnel de l’université de Mons

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2016-01-29 - Colloque/Présentation - poster - Anglais - 1 page(s)

Dupont Nicolas , Pacyna Daniel, Mortier Thierry , Baele Jean-Marc , "The Colfontaine forest : vestiges of multi-secular an multi-ressources extractive activities in the Mons Basin Geopark" in 5th International Geologica Belgica Meeting, Mons, Belgique, 2016

  • Codes CREF : Géologie (DI1411), Ressources renouvelables et non-renouvelables (DI4383), Enseignement des sciences (DI0130), Histoire (DI5100), Exploitation des mines et carrières (DI2320)
  • Unités de recherche UMONS : Géologie fondamentale et appliquée (F401)
  • Instituts UMONS : Institut de Recherche en Science et Ingénierie des Matériaux (Matériaux), Institut de Recherche en Energétique (Energie)

Abstract(s) :

(Anglais) The Colfontaine forest is located southward the highly urbanised area called Borinage, wherein coal mining activities occurred from at least the 13th c. to 1976. Despite its low extent (8 km²), this forest has great geological interest: Palaeozoic formations are outcropping while they are essentially present under a thick Mesozoic cover in the Borinage. Moreover, some old quarries illustrate past extraction and use of geomaterials: coal, sandstone, limestone. The forest exposes a classical geological cross-section of the unconformity between the Upper Carboniferous coal measures and the Lower Devonian siltstones and sandstones (the “Midi Fault”). At regional scale, this unconformity consists of a faulted zone between the Ardenne Allochton and the Brabant Parautochton (or Haine-Sambre-Meuse Overturned Thrust Sheets). Within the faulted zone, a hectometric unit of highly fractured Lower Carboniferous limestones occurs in the Colfontaine forest. Several old quarries show that geomaterials were extracted within the forest at different ages : Lochkovian siltstones and sandstones for building (possibly from Gallo-Roman era, to Late Middle-Age), Visean limestones for lime and building (18th c.), and Upper Carboniferous coarse sandstones and quartzites for road ballast (19th-20th c.). Coal extraction is documented is the western part of the forest since the 14th century. Later collieries were present in this zone, the best known is called “Sauwartan”, closed in 1938. Ruins of the headframe and the sorting buildings of this colliery remain in the forest. Recently, LIDAR imaging from the Walloon administration have shown many surface evidences of pre-industrial coal extraction in the forest just east to the “Sauwartan” : dozens of old backfilled shafts have been detected and traces of outcropping coal mining along vertical seams have been highlighted. According to historical records, these evidences date prior the end of the 18th century. Because of the favourable geological context for coal extraction, the oldest evidences might date from the beginning of the coal extraction in this area.