Horseshoe Canyon Formation

The Horseshoe Canyon Formation is part of the Edmonton Series and is up to 230m in thickness. It is Late Campanian to Early Maastrichtian in age (Edmontonian Land Mammal Age) and is composed of mudstone, sandstone, and carbonaceous shales. There are a variety of environments represented by the succession, including floodplains, estuarine channels, and coalswamps, which have yielded a diversity of fossil material. Tidally-influenced estuarine point bar deposits are easily recongizable as Inclined Heterolithic Stratification (IHS). Brackish-water trace fossil assemblages occur within these bar deposits and demonstrate periodic incursion of marine waters into the estuaries. The Horseshoe Canyon Formation crops out extensively in the area of Drumheller, Alberta, as well as further north along the Red Deer River near Trochu, and also in the city of Edmonton. It is overlain by the Battle, Whitemud, and Scollard formations. The Drumheller Coal Zone, located in the lower part of the Horseshoe Canyon Formation, has been a primary CBM target for industry. In the area between Bashaw and Rockyford, the Drumheller Coal Zone is relatively shallow (about 300 metres) with 10 to 20 metres cumulative coal within a 70 to 120 metre coal zone thickness. The coal zone may contain 20 or more individual thin seams and interbedded sandstone and shale, which combine to make an attractive multi-completion CBM target for drilling companies. In total, it is estimated there are 14 trillion cubic metres (500 tcf) of gas in place in all the coal in Alberta.

Dinosaurs found in the Horseshoe Canyon Formation include "Albertosaurus", "Anchiceratops", "Arrhinoceratops", "Atrociraptor", "Chirostenotes", "Dromiceiomimus", "Edmontonia", "Edmontosaurus", "Euoplocephalus", "Hypacrosaurus", "Ornithomimus", "Pachyrhinosaurus", "Parksosaurus", "Saurolophus", "Stegoceras", "Struthiomimus" and "Troodon". Other finds have included mammals such as "Didelphodon coyi", non-dinosaur reptiles, amphibians, fish, marine and terrestrial invertebrates and plant fossils. Reptiles such as turtles and crocodilians are rare in the Horseshoe Canyon Formation, and this is thought to reflect the relatively cool climate which prevailed at the time.

Horseshoe Canyon itself is located 17 km southwest of Drumheller, Alberta, Canada, on Highway 9. This Canyon gets its name from its horseshoe shape and is approximately 3 km long, extending from Highway 9 to Kneehill Creek area.

Dinosaurs

Theropoda (Currie, 2005):Coelurosauria incertae sedis::Family unknown:::*"Ricardoestesia isosceles":Tyrannosauroidea::Tyrannosauridae :::*"Albertosaurus sarcophagus":Ornithomimosauria::Ornithomimidae:::*"Dromiceiomimus brevitertius" (may be synonymous with "Ornithomimus edmontonicus)":::*"Ornithomimus edmontonicus":::*"Struthiomimus altus":Maniraptora::Caenagnathidae:::*"Chirostenotes pergracilis"::Troodontidae:::*"Troodon formosus"::Dromaeosauridae:::*"Atrociraptor marshalli":::*"Dromaeosaurus" sp.:::*"Saurornitholestes" sp.

Ornithischia (Ryan and Evans, 2005):Ankylosauria::Ankylosauridae:::*"Euoplocephalus tutus"::Nodosauridae:::*"Edmontonia longiceps":Pachycephalosauria::Pachycephalosauridae:::*"Stegoceras edmontonense" (?"Prenocephale"):Ceratopsia::Ceratopsidae:::Centrosaurinae:::*"Pachyrhinosaurus canadensis":::Chasmosaurinae:::*"Anchiceratops ornatus":::*"Arrhinoceratops brachyops":::*"Eotriceratops xerinsularis‏" (found within the upper 20 m of the formation):Ornithopoda:::*"Parksosaurus warrenae"::Hadrosauridae:::Hadrosaurinae:::*"Edmontosaurus regalis":::*"Saurolophus osborni":::Lambeosaurinae:::*"Hypacrosaurus altispinus"

ee also

* List of dinosaur-bearing rock formations