The information on this page is a summary description.
The full formal description is available here: Grand Ri Member
| Abbreviation | GRI |
| Parent unit | Wépion Formation |
| Child units | |
| Lithological description | Green quartzite beds with a conglomeratic base, blue-grey, greenish or reddish sandstone and quartzite alternating with thickly bedded, grey, green or red shale and siltstone. |
| Age | Emsian |
| Thickness | 260 metres in the type locality |
| Area of occurrence | North and eastern margins of the Dinant Synclinorium, up to the Mormont Fault. |
| Type locality | After Grand Ri locality in Wépion, in the Meuse River valley. |
| Alternative names | Grès de Wépion |
| Authors | Denayer, J. & Mottequin, B. |
| Date | 23/09/2025 |
| Cite as | Denayer, J. & Mottequin, B., 2025. The Grand Ri Member, 23/09/2025. National Commission for Stratigraphy Belgium. https://ncs.naturalsciences.be/lithostratigraphy/Grand-Ri-Member |
| Additional information |
