Horseshoe Canyon Formation


The Horseshoe Canyon Formation is a stratigraphic unit of the Western Canada Sedimentary Basin in southwestern Alberta. It takes its name from Horseshoe Canyon, an area of badlands near Drumheller.
The Horseshoe Canyon Formation is part of the Edmonton Group and is up to thick. It is of Late Cretaceous age, Campanian to early Maastrichtian stage, and is composed of mudstone, sandstone, carbonaceous shales, and coal seams. A variety of depositional environments are represented in the succession, including floodplains, estuarine channels, and coal swamps, which have yielded a diversity of fossil material. Tidally-influenced estuarine point bar deposits are easily recognizable as Inclined Heterolithic Stratification. 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 around Drumheller, as well as farther north along the Red Deer River near Trochu and along the North Saskatchewan River in 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, was mined for sub-bituminous coal in the Drumheller area from 1911 to 1979, and the Atlas Coal Mine in Drumheller has been preserved as a National Historic Site. In more recent times, the Horseshoe Canyon Formation has become a major target for coalbed methane production.
Dinosaurs found in the Horseshoe Canyon Formation include Albertavenator, Albertosaurus, Anchiceratops, Anodontosaurus, Arrhinoceratops, Atrociraptor, Epichirostenotes, Edmontonia, Edmontosaurus, Hypacrosaurus, Ornithomimus, Pachyrhinosaurus, Parksosaurus, Saurolophus, and Struthiomimus. 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 was thought to reflect the relatively cool climate which prevailed at the time. A study by Quinney et al. however, showed that the decline in turtle diversity, which was previously attributed to climate, coincided instead with changes in soil drainage conditions, and was limited by aridity, landscape instability, and migratory barriers.

Oil/gas production

The Drumheller Coal Zone has been a primary coalbed methane target for industry. In the area between Bashaw and Rockyford, the Coal Zone lies at relatively shallow depths and is about 70 to 120 metres thick. It contains 10 to 20 metres of cumulative coal, in up to 20 or more individual thin seams interbedded with sandstone and shale, which combine to make an attractive multi-completion CBM drilling target. In total, it is estimated there are 14 trillion cubic metres of gas in place in all the coal in Alberta.

Biostratigraphy

The timeline below follows work by David A. Eberth and Sandra L. Kamo published in 2019.

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from: -68.0 till: -67.2 color:triassic text:-
from: -73.2 till: -68.0 color:jurassic text:Horseshoe Canyon Formation
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from: -72.1 till: -67.2 color:mesozoic text:Maastrichtian
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color:HER bar:NAM1 from:-72.7 till:-71.9 text:Pachyrhinosaurus canadensis
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color:CAR bar:NAM3 from:-72.5 till:-69.6 text:Ornithomimus edmontonicus
color:ANK bar:NAM4 from:-72.2 till:-70.8 text:Anodontosaurus lambei
color:HER bar:NAM5 from:-72.6 till:-70.3 text:Anchiceratops ornatus
color:HAD bar:NAM6 from:-73.0 till:-71.5 text:Edmontosaurus regalis
color:CAR bar:NAM7 from:-73.0 till:-69.6 text:Albertosaurus sarcophagus
color:ANK bar:NAM8 from:-71.8 till:-71.5 text:Edmontonia longiceps
color:HER bar:NAM9 from:-72.3 till:-70.5 text:Arrhinoceratops brachyops
color:HAD bar:NAM10 from:-71.5 till:-69.6 text:Hypacrosaurus altispinus
color:HAD bar:NAM11 from:-70.9 till:-69.6 text:Saurolophus osborni
color:HER bar:NAM12 from:-70.8 till:-70.5 text:Sphaerotholus edmontonense
color:HER bar:NAM13 from:-70.9 till:-69.8 text:Parksosaurus warreni
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from: -70.9 till: -69.6 color:jurassic text:Tolman M.
from: -71.5 till: -70.9 color:triassic text:Morrin M.
from: -72.3 till: -71.5 color:jurassic text:Horsethief M.
from: -73.2 till: -72.3 color:triassic text:Drumheller M.
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Dinosaurs

Ankylosaurs

Maniraptors

Marginocephalians

Ornithomimids

Hadrosaurs and thescelosaurs

Tyrannosaurs

Other Animals

Mammals

Other Reptiles

Fish