Scollard Formation, Geological formation in Alberta, Canada

The Scollard Formation is an Upper Cretaceous to lower Paleocene stratigraphic unit of the Western Canada Sedimentary Basin in southwestern Alberta. It consists mainly of sandstones and siltstones interbedded with mudstones, minor bentonite, and, in its upper member, the coal seams of the Ardley coal zone. It is divided into a coal-bearing upper member and a lower member lacking significant coal, neither formally named. It outcrops along the banks of the Red Deer River near Trochu.

The Scollard Formation spans the Cretaceous-Paleogene boundary, which lies at the base of the lowermost seam of the Ardley coal zone, identified from dinosaurian and microfloral evidence and a terminal Cretaceous iridium anomaly. Its lower member is latest Maastrichtian in age and records the last dinosaurs; the upper, coal-bearing member is early Danian and records the rise of mammals after the extinction.

The formation's name comes from Scollard, Alberta, and its Ardley coal zone has long been mined: coal was worked in the Red Deer area and is still mined west of Edmonton to feed mine-mouth power stations. The canyon-like exposures along the Red Deer River near Trochu are the classic place to see the Ardley seams.

The formation is not a site with marked trails or facilities; its beds are best seen in natural exposures along the banks of the Red Deer River near Trochu, where the strata are cut by the river. Access depends on land ownership and river conditions, so check locally before setting out. The beds also lie in the subsurface across much of southwestern Alberta.

The K-Pg boundary sits at the base of the lowest Ardley coal seam, identified through dinosaurian and microfloral evidence and a terminal Cretaceous iridium anomaly. The overlying coal is sub-bituminous B to C rank, reaching high-volatile bituminous rank farther west, and seams exceed 7 metres in places. The Ardley coal has been mined near Red Deer and is mined west of Edmonton to fuel mine-mouth power stations.