Horseshoe Canyon Formation | |
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Stratigraphic range: Campanian-Maastrichtian ~ [1] | |
![]() Horseshoe Canyon Formation at Horsethief Canyon, near Drumheller. The dark bands are coal seams. | |
Type | Geological formation |
Unit of | Edmonton Group |
Sub-units | Strathmore Member, Drumheller Member, Horsethief Member, Morrin Member, Tolman Member, Carbon Member, Whitemud Member |
Underlies | Battle Formation, Scollard Formation |
Overlies | Bearpaw Formation |
Lithology | |
Primary | Sandstone |
Other | Shale, coal |
Location | |
Coordinates | 51°25′24″N112°53′18″W / 51.42333°N 112.88833°W |
Region | ![]() Western Canadian Sedimentary Basin |
Country | ![]() |
Type section | |
Named for | Horseshoe Canyon |
Named by | E.J.W. Irish, 1970 |
The Horseshoe Canyon Formation is a stratigraphic unit of the Western Canada Sedimentary Basin in southwestern Alberta. [2] [3] It takes its name from Horseshoe Canyon, an area of badlands near Drumheller.
The Horseshoe Canyon Formation is part of the Edmonton Group. In its type section (Red Deer River Valley at Drumheller), it is ~250 metres (820 ft) thick, but further west the formation is older and thicker, exceeding 500 metres (1,600 ft) near Calgary. [4] It is of Late Cretaceous age, Campanian to early Maastrichtian stage (Edmontonian Land-Mammal Age), 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 (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 around Drumheller, as well as farther north along the Red Deer River near Trochu and along the North Saskatchewan River in Edmonton. [2] It is overlain by the Battle and Scollard formations. [4] 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. [5] In more recent times, the Horseshoe Canyon Formation has become a major target for coalbed methane (CBM) 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. (2013) 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. [6]
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 (about 300 metres) 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 (500 tcf) of gas in place in all the coal in Alberta.
The timeline below follows work by David A. Eberth and Sandra L. Kamo published in 2019. [7]
Ankylosaurs reported from the Horseshoe Canyon Formation | |||||
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Genus | Species | Stratigraphic position | Material | Notes | Images |
[Five] skulls, mandibles, cervical vertebra, caudal vertebrae, dorsal vertebrae, sacrocaudal vertebrae, sacrum, illium, ischium, partial pelvis, coossified ribs, femur, ?manual phalanx, tail clubs, numerous cervical half-rings and osteoderms. [8] [9] | An ankylosaurine ankylosaurid also known from the middle Dinosaur Park Formation and closely related to Ankylosaurus . [10] | ![]() | |||
E. longiceps [11] | Upper Horsethief [11] | A skull with mandible, dorsal vertebrae, dorsal vertebrae, sacral vertebrae, caudal vertebrae, cervical ribs, dorsal ribs, humerus, radius, ulna, radius, ilia, ischia, both pubes (?), femur, tibia, fibula and osteoderms. [11] | A panoplosaurin nodosaurid also known from the lower Dinosaur Park Formation and closely related Denversaurus . [12] | ![]() | |
E. tutus | Walter Coombs (1971) synonymised Anodontosaurus lambei with E. tutus . However, recent studies suggest that Anodontosaurus is distinct enough from Euoplocephalus to be placed in its own genus and species. [8] [13] Furthermore, all Horseshoe Canyon Formation ankylosaurine specimens were suggested to be reassigned to Anodontosaurus. [9] | ![]() | |||
Hadrosaurs reported from the Horseshoe Canyon Formation | ||||||
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Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
Horsethief; likely present in Drumheller. | ![]() | |||||
H. altispinus | Morrin and Tolman. | "[Five to ten] articulated skulls, some associated with postcrania, isolated skull elements, isolated postcranial elements, many individuals, embryo to adult." [14] | ![]() | |||
S. osborni | Upper Morrin and Tolman. | "Complete skull and skeleton, [two] complete skulls." [14] | ![]() | |||
Color key
| Notes Uncertain or tentative taxa are in small text; |
Ceratopsians reported from the Horseshoe Canyon Formation | ||||||
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Genus | Species | Stratigraphic position | Material | Notes | Images | |
Horsethief, Morrin, and Tolman; may have been present in Drumheller [16] | [Two] nearly complete skulls and [seven] partial skulls. [16] | A chasmosaurine ceratopsid contemporaneous and closely related to Arrhinoceratops . [16] | ![]() | |||
A. brachyops [17] | Horsethief [17] | A nearly complete skull. [17] | A chasmosaurine ceratopsid restricted to the holotype specimen as Farke (2007) assigned the referred specimen ROM 1439 to Torosaurus . [18] | | ||
E. xerinsularis [19] | Carbon [19] | Premaxillae, maxillae, rostral, supraorbital horncore with lacrimal, prefrontal, frontal, postorbital, jugal, epijugal, quadratojugal, quadrate, partial parietal, squamosal frill, braincase, syncervical, cervical vertebrae, dorsal vertebrae, ribs and fragments of ossified ligaments. [19] | A large chasmosaurine ceratopsid that may represent a senior synonym of Ojoceratops from the Ojo Alamo Formation. [20] | ![]() | ||
Upper Tolman [22] | An isolated braincase. [22] | A leptoceratopsid ceratopsian also known from the St. Mary River Formation. [21] | ![]() | |||
P. canadensis [23] | Drumheller and Horsethief [23] | [Two] partial skulls. [23] | A centrosaurine ceratopsid also known from the St. Mary River Formation. [23] | ![]() |
Pachycephalosaurids reported from the Horseshoe Canyon Formation | ||||||
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Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
S. edmontonense [25] | Tolman [24] | A pachycephalosaurine pachycephalosaurid also known from the Hell Creek and Kirtland Formation. [25] | ![]() |
Thescelosaurids reported from the Horseshoe Canyon Formation | ||||||
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Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
P. warreni | Tolman | A partially articulated skeleton and partial skull. | A thescelosaurid neornithischian. |
Maniraptors reported from the Horseshoe Canyon Formation | ||||||
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Genus | Species | Stratigraphic position | Material | Notes | Images | |
A. curriei [26] | Horsethief [26] | [Two] frontals. [26] | A troodontid theropod that adds to the diversity of North American troodontids. [26] | |||
A. borealis [27] | Upper Tolman [27] | Ulna, tibiae, metatarsals, manual ungual, pedal phalanxes and unidentified pedal phalanges. [27] | An mononykin alvarezsaurid specialized for digging insect nests. [27] | ![]() | ||
A. pennatus [28] | Horsethief [28] | A palatine, mandibles, ceratobranchials, axis, cervical vertebrae, dorsal vertebrae, pectoral girdles, sternal plate, forelimb, ilium, femur, tibia and fibula. [28] | A caenagnathid oviraptorosaur recovered as sister taxon to Elmisaurus . [28] | ![]() | ||
A. marshalli [29] | Lower Horsethief [29] | Premaxillae, maxilla, dentaries, teeth and numerous bone fragments. [29] | A dromaeosaurid; teeth indicate it may have been present across all members. [29] | ![]() | ||
E. curriei [30] | Horsethief, Morrin, and Tolman [30] | A maxilla, probable palatine, partial braincase, cervical vertebrae, dorsal vertebrae, caudal vertebrae, synsacrum, an anterior and a posterior cervical rib, a mid-dorsal rib, fragments of ilia, ischium, both pubes, partial tibia, and unidentifiable bones. [30] | A caenagnathid oviraptorosaur known from material previously assigned to Chirostenotes . [30] | ![]() | ||
Color key
| Notes Uncertain or tentative taxa are in small text; |
Ornithomimids reported from the Horseshoe Canyon Formation | ||||||
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Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
D. brevitertius | Several specimens. type specimen | An ornithomimid | ![]() | |||
O. currelli | Junior synonym of O. edmontonicus | |||||
O. edmontonicus | Drumheller, Horsethief, Morrin, and Tolman | Several specimens, type specimen | An ornithomimid | ![]() | ||
S. altus | Drumheller, Horsethief, and Morrin | An ornithomimid | ![]() |
Color key
| Notes Uncertain or tentative taxa are in small text; |
Tyrannosaurids reported from the Horseshoe Canyon Formation | ||||||
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Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
A. arctunguis | Junior synonym of A. sarcophagus | ![]() | ||||
A. sarcophagus | Horsethief, Morrin, and Tolman; likely present in Drumheller and Carbon. | Several skeletons and partial skeletons, type specimen | A tyrannosaurid which was the most common large carnivore in the area. [31] [32] | |||
D. sp. | Suggested from the skeleton of an immature tyrannosaurid (CMN 11315), thorough analysis of this specimen supports a referral to A. sarcophagus. [33] An isolated maxilla and teeth from an Edmontosaurus bonebed were also mistakenly referred to Daspletosaurus, however all the tyrannosaurid material in the bonebed was confirmed to belong to A. sarcophagus. [34] | |||||
Color key
| Notes Uncertain or tentative taxa are in small text; |
Mammals reported from the Horseshoe Canyon Formation | ||||||
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Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
D. coyi | ![]() |
Color key
| Notes Uncertain or tentative taxa are in small text; |
Reptiles reported from the Horseshoe Canyon Formation | ||||||
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Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
S. mccabei | "a skull, partial lower jaws, and partial postcranial skeleton" | An alligatoroid | ||||
C. albertensis | "partial skeleton with partial skull" | ![]() | ||||
L. ultimus | "a partial skeleton" | a plesiosaur of uncertain classification | ||||
B. morrinensis | "nearly complete shell" |
Color key
| Notes Uncertain or tentative taxa are in small text; |
Fish reported from the Horseshoe Canyon Formation | ||||||
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Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
Boreiosturion [40] | B. labyrinthicus | Edmonton. | Partial skull. | A sturgeon. | ||
H. armaserratus |
Albertosaurus is a genus of large tyrannosaurid theropod dinosaur that lived in northwestern North America during the early to middle Maastrichtian age of the Late Cretaceous period, about 71 million years ago. The type species, A. sarcophagus, was apparently restricted in range to the modern-day Canadian province of Alberta, after which the genus is named, although an indeterminate species has been discovered in the Corral de Enmedio and Packard Formations of Mexico. Scientists disagree on the content of the genus and some recognize Gorgosaurus libratus as a second species.
Troodon is a former wastebasket taxon and a potentially dubious genus of relatively small, bird-like theropod dinosaurs definitively known from the Campanian age of the Late Cretaceous period. It includes at least one species, Troodon formosus, known from Montana. Discovered in October 1855, T. formosus was among the first dinosaurs found in North America, although it was thought to be a lizard until 1877. Several well-known troodontid specimens from the Dinosaur Park Formation in Alberta were once believed to be members of this genus. However, recent analyses in 2017 have found this genus to be undiagnostic and referred some of these specimens to the genus Stenonychosaurus some to the genus Latenivenatrix, and some to the genus Pectinodon. The genus name is Ancient Greek for "wounding tooth", referring to the teeth, which were different from those of most other theropods known at the time of their discovery. The teeth bear prominent, apically oriented serrations. These "wounding" serrations, however, are morphometrically more similar to those of herbivorous reptiles, and suggest a possibly omnivorous diet.
A bone bed is any geological stratum or deposit that contains bones of whatever kind. Inevitably, such deposits are sedimentary in nature. Not a formal term, it tends to be used more to describe especially dense collections such as Lagerstätte. It is also applied to brecciated and stalagmitic deposits on the floor of caves, which frequently contain osseous remains.
Pachyrhinosaurus is an extinct genus of centrosaurine ceratopsid dinosaur from the Late Cretaceous period of North America. The first examples were discovered by Charles M. Sternberg in Alberta, Canada, in 1946, and named in 1950. Over a dozen partial skulls and a large assortment of other fossils from various species have been found in Alberta and Alaska. A great number were not available for study until the 1980s, resulting in a relatively recent increase of interest in Pachyrhinosaurus.
Atrociraptor is a genus of dromaeosaurid dinosaur that lived during the Late Cretaceous in what is now Alberta, Canada. The first specimen, a partial skull, was discovered in 1995 by the fossil collector Wayne Marshall in the Horseshoe Canyon Formation, about 5 km (3 mi) from the Royal Tyrrell Museum of Palaeontology, where it was brought for preparation. In 2004, the specimen became the holotype of the new genus and species Atrociraptor marshalli; the generic name is Latin for "savage robber", and the specific name refers to Marshall. The holotype consists of the premaxillae, a maxilla, the dentaries, associated teeth, and other skull fragments. Isolated teeth from the same formation have since been assigned to Atrociraptor.
Struthiomimus, meaning "ostrich-mimic", is a genus of ornithomimid dinosaurs from the late Cretaceous of North America. Ornithomimids were long-legged, bipedal, ostrich-like dinosaurs with toothless beaks. The type species, Struthiomimus altus, is one of the more common, smaller dinosaurs found in Dinosaur Provincial Park; their overall abundance—in addition to their toothless beak—suggests that these animals were mainly herbivorous or omnivorous, rather than purely carnivorous. Similar to the modern extant ostriches, emus, and rheas, ornithomimid dinosaurs likely lived as opportunistic omnivores, supplementing a largely plant-based diet with a variety of small mammals, reptiles, amphibians, insects, invertebrates, and anything else they could fit into their mouth, as they foraged.
Dromiceiomimus is a genus of ornithomimid theropod from the Late Cretaceous of Alberta, Canada. The type species, D. brevitertius, is considered a synonym of Ornithomimus edmontonicus by some authors, while others consider it a distinct and valid taxon. It was a small ornithomimid that weighed about 135 kilograms (298 lb).
Philip John Currie is a Canadian palaeontologist and museum curator who helped found the Royal Tyrrell Museum of Palaeontology in Drumheller, Alberta and is now a professor at the University of Alberta in Edmonton. In the 1980s, he became the director of the Canada-China Dinosaur Project, the first cooperative palaeontological partnering between China and the West since the Central Asiatic Expeditions in the 1920s, and helped describe some of the first feathered dinosaurs. He is one of the primary editors of the influential Encyclopedia of Dinosaurs, and his areas of expertise include theropods, the origin of birds, and dinosaurian migration patterns and herding behavior. He was one of the models for palaeontologist Alan Grant in the film Jurassic Park.
Anchiceratops is an extinct genus of chasmosaurine ceratopsid dinosaur that lived approximately 72 to 71 million years ago during the latter part of the Cretaceous Period in what is now Alberta, Canada. Anchiceratops was a medium-sized, heavily built, ground-dwelling, quadrupedal herbivore that could grow up to an estimated 4.3 metres (14 ft) long. Its skull featured two long brow horns and a short horn on the nose. The skull frill was elongated and rectangular, its edges adorned by coarse triangular projections. About a dozen skulls of the genus have been found.
Chirostenotes is a genus of oviraptorosaurian dinosaur from the late Cretaceous of Alberta, Canada. The type species is Chirostenotes pergracilis.
Montanoceratops is an extinct genus of small ceratopsian dinosaur that lived approximately 70 million years ago during the latter part of the Cretaceous Period in what is now Montana and Alberta. Montanoceratops was a small sized, moderately-built, ground-dwelling, quadrupedal herbivore, that could grow up to an estimated 2.5 m (8.2 ft) in length and 170 kg (370 lb) in body mass.
Anodontosaurus is an extinct genus of ankylosaurid dinosaurs within the subfamily Ankylosaurinae. It is known from the entire span of the Late Cretaceous Horseshoe Canyon Formation of southern Alberta, Canada, and is also known from the Dinosaur Park Formation. It contains two species, A. lambei and A. inceptus.
The Oldman Formation is a stratigraphic unit of Late Cretaceous age that underlies much of southern Alberta, Canada. It consists primarily of sandstones that were deposited in fluvial channel and floodplain environments. It was named for exposures along the Oldman River between its confluence with the St. Mary River and the city of Lethbridge, and it is known primarily for its dinosaur remains and other fossils.
Caenagnathidae is a family of derived caenagnathoid dinosaurs from the Cretaceous of North America and Asia. They are a member of the Oviraptorosauria, and relatives of the Oviraptoridae. Like other oviraptorosaurs, caenagnathids had specialized beaks, long necks, and short tails, and would have been covered in feathers. The relationships of caenagnathids were long a puzzle. The family was originally named by Raymond Martin Sternberg in 1940 as a family of flightless birds. The discovery of skeletons of the related oviraptorids revealed that they were in fact non-avian theropods, and the discovery of more complete caenagnathid remains revealed that Chirostenotes pergracilis, originally named on the basis of a pair of hands, and Citipes elegans, originally thought to be an ornithomimid, named from a foot, were caenagnathids as well.
Edmontosaurus regalis is a species of comb-crested hadrosaurid dinosaur. Fossils of E. regalis have been found in rocks of western North America that date from the late Campanian age of the Cretaceous Period 73 million years ago, but it may have possibly lived into the early Maastrichtian.
The Foremost Formation is a stratigraphic unit of Late Cretaceous (Campanian) age that underlies much of southern Alberta, Canada. It was named for outcrops in Chin Coulee near the town of Foremost and is known primarily for its dinosaur remains and other fossils.
Albertavenator is a genus of small troodontid theropod dinosaur, known from the early Maastrichtian in the Cretaceous period. It contains a single species, A. curriei, named after paleontologist Phil Currie, based on a partial left frontal found in the Horseshoe Canyon Formation of Alberta during the 1990s. Albertavenator's discovery indicates that small dinosaur diversity may be underestimated at present due to the difficulty in identifying species from fragmentary remains.
David Christopher Evans is a Canadian palaeontologist and evolutionary biologist who specializes in the evolution and paleobiology of Cretaceous dinosaurs in western North America. He received his B.Sc. from the University of British Columbia and his Ph.D. from the University of Toronto. He is a fellow of the Royal Canadian Geographical Society (RCGS) and a member of the Royal Society of Canada and currently serves as the Senior Curator and Temerty Chair of Vertebrate Paleontology at the Royal Ontario Museum in Toronto, Canada. He is also a faculty member in the Department of Ecology & Evolutionary Biology at the University of Toronto. Evans is particularly renowned for his work on the paleobiology of hadrosaur ("duck-billed") dinosaurs and has conducted international research on a wide variety of paleontological topics.
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