Herald Formation

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.

Lithology
The Herald Formation is composed of dolomitic limestone and dolomite, which can be microcrystalline, argillaceous or microlaminated. In the centre of the basin, it is represented by anhydrite.

Distribution
The Herald Formation reaches a maximum thickness of 38 m in the Lake Alma area.

Relationship to other units
The Herald Formation is disconformably overlain by the Stony Mountain Formation and conformably overlays the Yeoman Formation.

It can be correlated with the Fort Garry Member of the Red River Formation in Manitoba and in the Williston Basin.

Subdivisions
In south-eastern Saskatchewan, the formation is divided in three units, corresponding to three sedimentation cycles:
 * Lake Alma Member
 * Coronach Member
 * Redvers Unit