The information on this page is a summary description.
The full formal description is available here: Trivières Chalk Formation
| Abbreviation | TRI |
| Parent unit | Chalk group |
| Child units | |
| Lithological description | A white to greyish marly chalk without flints. A conglomerate, from a few cm to one m thick, generally marks the base containing hardground fragments, phosphatised chalk nodules, phosphatised sponges and fossil fragments. The top is often a hardground (named “durillon” by the quarry workers). To the east of the Mons Basin several hardgrounds corresponding to large channels are distributed within this formation. Fossils are not abundant except in the basal conglomerate. |
| Age | Early-Late Campanian – cephalopods: Gonioteuthis quadrata, Belemnitella gr.mucronata, Scaphites gibbus; bivalves: Oxytoma tenuicostata, Endocostea baltica; echinoids: Echinocorys gr.ovata, Micraster schroederi. |
| Thickness | More than 10 m in the southern part of the Basin to 120 m in the northern part. |
| Area of occurrence | Mons Basin, in quarries and boreholes. |
| Type locality | No stratotype has been designated for the Trivières Fm. Depending on the activities at the cement quarries it is occasionally visible at Harmignies (C.C.C.) and Obourg (C.B.R.). |
| Alternative names | |
| Authors | Robaszynski, F., Dhondt, A.V. & Jagt, J.W.M. |
| Date | 01/01/2001 |
| Cite as | Robaszynski, F., Dhondt, A.V. & Jagt, J.W.M., 2001. The Trivières Chalk Formation, 01/01/2001. National Commission for Stratigraphy Belgium. https://ncs.naturalsciences.be/lithostratigraphy/Trivieres-Chalk-Formation |
| Additional information | References: J. Cornet (1923), Leriche (1935), Marlière (1936a, b, 1957), Robaszynski & Christensen (1989), Robaszynski (1995), Christensen (1999). |
