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Sedimentology, facies and depositional environment of the Hanonet (Upper Eifelian) and Trois-Fontaines (Lower Givetian) formations in Couvin area (Dinant Basin, Belgium)

par Préat, Alain
Référence Bulletin - Societe Belge de Geologie, 98, 2, page (149-154)
Publication Publié, 1989

Article révisé par les pairs

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Résumé :

During Middle Devonian (Eifelian) times a major sea-level rise led to the development of an extensive siliciclastic-carbonate ramp over the Dinant and Namur basins. The evolution of this continental margin leads to a good understanding of shelf evolution from Eifelian to Frasnian times. An initial mixed ramp (Eifelian) consisting mainly of organic buildups and shoal-water complexes evolved into a carbonate progradational accretionary platform consisting of shallowing-upward subtidal to supratidal cycles that grade locally into evaporite-carbonate cycles along an arid coastline. This cyclic sedimentation was interrupted during a major event of incipient shelf drowning associated with backstepping of the rim and development of algal-sponge bioherms on a low-ramp continental slope environment. Microfacies analysis of the Hanonet and Trois-Fontaines formations shows that the transition from Eifelian to Givetian times is marked by an entire regressive progradational megasequence partly interrupted by minor transgressive phases. Three distinct zones can be recognized. -from Author