| Herald Formation | |
| Type: | Geological formation |
| Period: | Late Ordovician |
| Prilithology: | limestone, dolomite, anhydrite |
| Namedby: | Saskatchewan Geological Society, 1958. |
| Region: | WCSB |
| Country: |  Canada |
| Coordinates: | 49.0746°N -104.6521°W |
| Subunits: | Lake Alma Member Coronach Member Redvers Unit |
| Underlies: | Stony Mountain Formation |
| Overlies: | Yeoman Formation |
| Thickness: | up to 38m (125feet) |
The Herald Formation is a stratigraphical 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.[1]
The Herald Formation is composed of dolomitic limestone and dolomite, which can be microcrystalline, argillaceous or microlaminated.[2] In the centre of the basin, it is represented by anhydrite.
The Herald Formation reaches a maximum thickness of 38m (125feet) in the Lake Alma area.[2]
The Herald Formation is disconformably overlain by the Stony Mountain Formation and conformably overlays the Yeoman Formation.[2]
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: