• Citer

Microfaciès et cyclicité dans le Givetien supérieur de Fromelennes (Synclinorium de Dinant, France).

par Préat, Alain ;Carliez, Dimitri
Référence Annales de la Société géologique de Belgique, 117, 1, page (227-243)
Publication Publié, 1996

Article révisé par les pairs

• Détails
• Contenu

Résumé :

The focus of this paper is on the small-scale cyclicity of the Fromelennes Formation (upper Givetian), and how stacking patterns of meter-scale cycles (fifth-order cycles) can be used to define internal components of a larger-scale sequence (third-order) and estimate variations in relative sea level. Thirty-seven asymetric parasequences (5th order cycles, averaging 2 m) are recognized and show two basic patterns: an upward-fining and -thinning parasequence (or, 'ufth'), and an aggradational parasequence (or, 'as'). Their stacking pattern allows recognition of six parasequences sets (PSQS1 to PSQS6) which are used to identify the upper part of a transgressive systems tract and the lower part of a highstand systems tract. Five periods of sea level fluctuations affected the very shallow part of a carbonate platform dominated by small-sized coral and stromatoporoid bioconstructions and extensive stromatolitic and codiacean algal mats.