| Herald Formation | |
|---|---|
| Stratigraphic range: | |
| Type | Geological formation |
| Sub-units | Lake Alma Member Coronach Member Redvers Unit |
| Underlies | Stony Mountain Formation |
| Overlies | Yeoman Formation |
| Thickness | up to 38 metres (120 ft) [1] |
| Lithology | |
| Primary | limestone, dolomite, anhydrite |
| Location | |
| Coordinates | 49°04′29″N104°39′08″W / 49.0746°N 104.6521°W |
| Region | WCSB |
| Country | Canada |
| Type section | |
| Named by | Saskatchewan Geological Society, 1958. |
The Herald Formation is a stratigraphic unit of Late Ordovician age in the Western Canadian Sedimentary Basin.
It was defined in well Imperial Herald 1-31-1-20W2M by the Lower Paleozoic Names and Correlations Committee of the Saskatchewan Geological Society in 1958. [2]
The Herald Formation is composed of dolomitic limestone and dolomite, which can be microcrystalline, argillaceous or microlaminated. [1] In the centre of the basin, it is represented by anhydrite.
The Herald Formation reaches a maximum thickness of 38 metres (120 ft) in the Lake Alma area. [1]
The Herald Formation is disconformably overlain by the Stony Mountain Formation and conformably overlays the Yeoman Formation. [1]
It can be correlated with the Fort Garry Member of the Red River Formation in Manitoba and in the Williston Basin.
In south-eastern Saskatchewan, the formation is divided in three units, corresponding to three sedimentation cycles: