2.2.4. Charleroi Formation
Authors: Renier, 1912, 1928; Delcambre & Pingot, 2000.
Description: The Charleroi Formation (originally defined as “Assise de Charleroi”) is characterised by a rhythmic succession of coal-mudstone-sandstone sequences. Coal seams are frequent and much thicker (up to 3 m). It was the main coal-producing unit in Belgium. Weakly marine incursions allow a further subdivision.
The following members have been distinguished (names and definition according to Renier, 1928; Delmer, 1963; Paproth et al., 1983), from bottom to top:
- Mons Member (base: Wasserfall = Stenaye = Gros Pierre marine band), formerly known as ‘Assise de Genk’. Parastratotype: Winterslag colliery, Campine coal field;
- As Member (base: Quaregnon = Katharina marine band; boundary Westphalian A - Westphalian B), named Quaregnon Member in Paproth et al. (1983). Stratotype: Waterschei colliery, Campine coal field;
- Eikenberg Member (base: Eisden = Domina marine band), named Eisden Member in Paproth et al. (1983). Stratotype: borehole KB14 Meeuwen-Eikenberg.
The Quaregnon marine band is not known in the thrusted massifs of the Hainaut basin; the Eisden marine band has not been recognised at all in the southern Belgian coal basins, thus limiting the possibilities for generalised subdivision of the Charleroi Formation.
The Charleroi Formation is conformably overlying the Châtelet Formation along the Gros Pierre = Wasserfall horizon. It is conformably succeeded by the Flénu Formation along the Maurage marine band.
Stratotype: Charleroi coal basin. Reference section trench of the canal Charleroi-Brussels in Gosselies (Delcambre & Pingot, 2000).
Area: The mining districts of the Campine basin and Namur-Vesdre synclinoria (= Wallonian basin) in Belgium and extending beyond the national boundaries into Carboniferous basins of neighbouring countries.
Thickness: Preserved thicknesses of 500 m (central part of Wallonian basin) up to 1300 m (Borinage) and 1100 m (northeastern Campine basin).
Age: Late Upper Bashkirian; upper Westphalian A to Westphalian B according to traditional subdivision.