1.2.3. Oignies Formation - OIG
Authors: Gosselet & Malaise, 1868; Gosselet, 1880a; Meilliez & Blieck, 1994c.
Description: Formation made up of detrital rocks of red colour. At the bottom, coarse-grained sandstones, with feldspathic lenses, changing upwards to finer-grained rocks (fine-grained sandstones, siltstones, shales). Sedimentological observations indicate an evolution from a marine environment to an exunded alluvial plain.
Stratotype: The best sections are situatedat Fépin (France), at the Moulin de Fétrogne along the Meuse, and N of the meeting of the Meuse and Risdoux rivers.
Area: S flank of the Dinant Synclinorium.
Thickness: < 210 m at the stratotype, 800-1000 m in the Dochamps area.
Age: Lochkovian, with a diachronous character. The Oignies Fm is younger to the W (Couvin area, Z Subzone; lower part of the BZ Oppel Miospore Biozone = Lochkovian-Pragian) and older to the E (Arville-Poix St-Hubert area, E of the Rocroi Massif, SibSubzone, MN Oppel Miospore Biozone = Lochkovian).