Cretaceous igneous-clast conglomerate in the Blairmore Group, Rocky Mountain foothills and adjacent subsurface (Bow Island Formation), Alberta, Canada

Several Albian-aged igneous pebble to cobble conglomerate channels are incised into finer- grained sediment of the Mill Creek and Beaver Mines formations (Blairmore Group) in the Rocky Mountain Foothills and Front Ranges in southwest Alberta and southeastern British Columbia. The channels can be traced intermittently along easterly trends for up to 66 km in several adjacent thrust slices. Correlative units in the Alberta subsurface occur in the Bow Island Formation of the Colorado Group. In the Foothills and Front Ranges, the conglomerate was deposited in a series of ten east-flowing, sub-parallel channels that flowed into the foreland basin perpendicular to the then-existing mountain front. The conglomerates originated from igneous and volcanic source terrains in the Omineca Belt of British Columbia which were 350 to 400 km away. The conglomerates were deposited in low-sinuousity braided rivers which were incised into regional finer-grained floodplain deposits of the upper Beaver Mines and Mill Creek formations. Individual conglomerate bodies are up to 60 m thick and can be traced laterally for up to 3 km. The largest conglomerate-filled valley, Bruin Channel, is approximately 22 km wide. Crowsnest Channel likely provided sediment and reservoir for the Blood Pool in the Bow Island Formation. This igneous-clast conglomerate was previously termed the "McDougall-Segur Conglomerate", a name which is stratigraphically inappropriate. This term should be abandoned.