First published: 14 June 2019
Last modified:
DISCLAIMER: This English version is translated from the original French. In case of any discrepancy, the French version shall prevail.
| Author: | Clark and Globensky, 1975 |
| Age: | Middle Ordovician |
| Stratotype: | Type section described by Clark and Globensky (1975) from drilling Gauthier No. 2 at the Gauthier Quarry, Saint-Marc-des-Carrières (46.6764º N, 72.0569º E) |
| Type area: | Saint-Marc-des Carrières area (NTS sheet 31I09) |
| Geological province: | St. Lawrence Platform |
| Geological subdivision: | St. Lawrence Lowlands Platform |
| Lithology: | Quartzitic sandstone |
| Category: | Lithostratigraphic |
| Rank: | Formation |
| Status: | Formal |
| Use: | Active |
- Trenton Group
- Tétreauville Formation
- Montréal Formation
- Neuville Formation
- Deschambault Formation
- Hull Formation
- Saint-Marc Formation
- Mile End Formation
- Ouareau Formation
- Fontaine Formation
- Pont-Rouge Formation
- Sainte-Anne Formation
- Galets Formation
- Shipshaw Formation
- Simard Formation
- Tremblay Formation
- René-Levasseur Formation
Background
Two diamond drillings in the Gauthier Quarry (in Saint-Marc-des-Carrières) crossed, under limestone of the Deschambault Formation, 8.8 and 11.3 m of quartzitic sandstone overlying gneiss. Although not outcropping and likely not widespread, Clark and Globensky (1975) considered it of sufficient importance to define the Saint-Marc Formation. The name refers to the town of Saint-Marc-des-Carrières (sheet 31I09) where drillings were conducted.
Description
The Saint-Marc Formation consists of a light, almost pure, well-sorted quartzitic sandstone (Clark and Globensky, 1975; Harland and Pickerill, 1982; Globensky, 1993). It contains limestone interbeds of the Deschambault Formation. This sandstone is interpreted as a shallow, subtidal, clastic sedimentary deposit from a local shoreline or near an island (Harland and Pickerill, 1982). The type section described below is taken from the bottom 11.3 m of driling Gauthier No. 2, in Saint-Marc-des-Carrières (Clark and Globensky, 1975):
| Deschambault Formation | Coarse, medium and fine-grained Deschambault-type crystalline limestone. | |
| Saint-Marc Formation | Sandstone | 0.3 m |
| Dark, dense, sublithographic limestone | 0.03 m | |
| Sandstone | 2.5 m | |
| Dark, dense, sublithographic limestone | 0.1 m | |
| Sandstone | 8.5 m | |
| Precambrian bedrock | Gneiss |
Thickness and distribution
In the two Gauthier Quarry drillings, the Saint-Marc Formation is 8.8 and 11.3 m thick (Clark and Globensky, 1975). This sandstone does not outcrop and has not been observed elsewhere.
Dating
None.
Stratigraphic Relationship(s)
The Saint-Marc Formation lies on Precambrian bedrock and contains interbeds of the Deschambault Formation, which relates it to the Lower Trenton Group (Clark and Globensky, 1975). In terms of its lithology and stratigraphic position, Saint-Marc Formation sandstone is very similar to that of the La Gabelle Formation, belonging to the Black River Group, underlying the Trenton Group.
Paleontology
No fossil was observed in the sandstone. However, in drilling Gauthier No. 1, typical bryozoans of the Deschambault Formation were observed in limestone interbeds (Clark and Globensky, 1975).
References
Publications Available Through SIGÉOM Examine
CLARK, T H., GLOBENSKY, Y. 1975. REGION DE GRONDINES. MRN. RG 154, 171 pages and 1 plan.
GLOBENSKY, Y. 1993. LEXIQUE STRATIGRAPHIQUE CANADIEN – VOLUME V-B – REGION DES APPALACHES, DES BASSES-TERRES DU SAINT-LAURENT ET DES ILES DE LA MADELEINE. MRN. DV 91-23, 336 pages.
Other Publications
HARLAND, T.L., PICKERILL, R.K. 1982. A review of Middle Ordovician sedimentation in the St. Lawrence Lowland, eastern Canada. Geological Journal; volume 17, pages 135-156. https://doi.org/10.1002/gj.3350170205