Publication details
Ivorian
| Authors | |
|---|---|
| Year of publication | 2006 |
| Type | Article in Periodical |
| Magazine / Source | Geologica Belgica |
| MU Faculty or unit | |
| Citation | |
| Field | Geology and mineralogy |
| Keywords | Upper Tournaisian Belgium |
| Description | S e Ivorian Substage is the upper division of the Tournaisian. Its base, emended in this paper, corresponds to the fi rst appearance of the conodont Polygnathus communis carina in the Yvoir railway station section. Its top is defi ned by the base of the Moliniacian Substage which corresponds now to the base of the Viséan. S e Ivorian is characterized by a rich and diversifi ed conodont fauna throughout and by a diversifi cation of the foraminifers in its upper part. It is therefore very well zoned and precisely correlated across the Franco-Belgian Basin and beyond. Its upper boundary is marked by a drastic reduction of the conodont fauna and the disappearance of selected Tournaisian foraminiferal taxa. Ivorian sedimentation refl ects the evolution of the Namur-Dinant Basin from a homoclinal ramp in the early Tournaisian to a broad shelf of regional extent in the late Tournaisian. Waulsortian buildups started growing in the distal part of the ramp during early Ivorian and formed a discontinuous barrier over the southwestern part of the Dinant Sedimentation Area. Distal peri-Waulsortian facies are dominated by cherty crinoidal wacke- to packstones, thick-bedded crinoidal packtsones, grainstones and dolostones. An oolitic grainstone, the Avins Mbr of the Longpré Fm, caps the Ivorian succession in the inner shelf. Proximal peri-Waulsortian facies are cherty crinoidal wacke- to packstones and purplish blue, poorly fossiliferous wacke- to packstones. |
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