Stonewall Formation


The Stonewall Formation is a stratigraphical unit of Late Ordovician to Early Silurian age in the Western Canadian Sedimentary Basin.
It takes the name from Stonewall, Manitoba, and was first described in the Stonewall quarry by E.M. Kindle in 1914.

Lithology

The Stonewall Formation is composed of finely crystalline dolomite, with a basal argillaceous and sandy dolomite. Two thin sandstone beds occur in the middle and at the top of the formation.
In the central Williston basin, the base is marked by an anhydrite bed.

Distribution

The Stonewall Formation occurs at surface in the Manitoba outcrop belt and in the sub-surface in the Williston Basin. It reaches a maximum thickness of.

Relationship to other units

The Stonewall Formation is overlain by the Interlake Group and sharply overlays the Stony Mountain Formation.