The information on this page is a summary description.
The full formal description is available here: Spiennes Chalk Formation
| Abbreviation | SPI |
| Parent unit | Chalk group |
| Child unit | |
| Lithological description | A white to whitish-grey, rather coarse-grained chalk, which becomes calcarenitic towards the top. It contains many large black to grey-brown cherts and some black chert bands, 10 to 60 cm thick (used by Neolithic man for tool making). At the base there occasionally is a thin layer of phosphatised chalk pebbles and inoceramid, echinoid and ostreid fragments and sponges; at the top sometimes a burrowed level. |
| Age | Late Late Campanian: fossil content: cephalopods: Belemnitella minor I Jeletzky, Bt. minor II Christensen; echinoids: Cardiaster granulosus, Echinocorys belgica; benthic foraminifers: Bolivinoides australis (4 to 6 pustules), Globorotalites hiltermanni, Gavelinella voltziana involutiformis, Eponides beisseli… |
| Thickness | 20 to 25 m on the margin of the Mons Basin (e.g. at Harmignies) to 50 m in the centre of this basin in its most subsided zones. |
| Area of occurrence | Mons Basin, from Hautrage in the west to Havré in the east, in outcrops and boreholes. |
| Type locality | No stratotype has been designated for the Spiennes Formation. Outcrops are occasionally available depending on activities in quarries. A good section exposing the Spiennes Fm. pro parte was studied by Robaszynski & Christensen (1989). |
| 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 Spiennes Chalk Formation, 01/01/2001. National Commission for Stratigraphy Belgium. http://ncs.naturalsciences.be/lithostratigraphy/Spiennes-Chalk-Formation |
