Oldman Formation Explained

Oldman Formation
Type:	Geological formation
Age:	Campanian,
Period:	Campanian
Prilithology:	Sandstone
Otherlithology:	Mudstone and bentonite
Namedfor:	Oldman River
Namedby:	Russell, L.S. and Landes, R.W.
Year Ts:	1940^[1]
Region:	Western Canada Sedimentary Basin
Country:	Canada
Unitof:	Belly River Group
Underlies:	Dinosaur Park Formation
Overlies:	Foremost Formation
Thickness:	up to 328feet^[2]

The Oldman Formation is a stratigraphic unit of Late Cretaceous (Campanian stage) 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.^[3]

Lithology

The Oldman Formation is composed primarily of light-colored, fine-grained sandstones. They are upward-fining, lenticular to sheet-like bodies that are yellowish, steep-faced and blocky in outcrop. The formation also includes lesser amounts of siltstone and mudstone.^[4]

Depositional environments

The sediments of the Oldman Formation were deposited in fluvial channels (the sandstones) and a variety of channel margin, overbank and floodplain environments (the siltstones and mudstones). The formation is about 40m (130feet) thick at Dinosaur Provincial Park in southeastern Alberta. It thickens toward the southwest, and northwestern Montana appears to have been the primary source of the sediments.

Relationship to other units

The Oldman Formation is a member of the Belly River Group (also known as the Judith River Group). It conformably overlies the Foremost Formation, and is separated from the overlying Dinosaur Park Formation by a regional disconformity. The sediments of the Oldman are superficially similar to those of the Dinosaur Park, which was included in the Oldman Formation prior to the recognition of the disconformity. The two formations can also be distinguished by petrographic and sedimentologic differences.

Age

The Oldman Formation was deposited during the middle Campanian, between about 77.5 and 76.5 million years ago.^[5] It lies fully within magnetic polarity Chron 33n.^[6]

Fossil content

List of dinosaurs found in the formation:^{[5] [7]}

Theropods

Theropods of the Oldman Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Daspletosaurus	D. torosus		Lower	Several specimens with a complete skeleton	A tyrannosaurid
	Unnamed species^[8]		Upper	A skull	A new species of tyrannosaurid
Dromaeosaurus	Indeterminate			Teeth	A dromaeosaurid
cf. Hesperonychus^[9]	Indeterminate			Foot claw	A dromaeosaurid or an avialan^[10]
Paronychodon	Indeterminate			Teeth	A troodontid
Prismatoolithus^[11]	P. levis			Partial clutch containing 12 eggs
Ricardoestesia	R. isosceles				Misreported
	Indeterminate			Teeth	A dromaeosaurid
Saurornitholestes	S. langstoni			Partial remains	A dromaeosaurid
Troodon	Dubious			Teeth, eggs, embryos	A dubious taxon of troodontid, most specimens formerly considered Troodon have been reassigned to other genera such as Stenonychosaurus
Struthiomimus	S. altus			Several specimens, including a nearly complete skeleton^[12]	An ornithomimid

Ornithischians

Ornithischians of the Oldman Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Albertaceratops	A. nesmoi		Lower	Single Skull	A ceratopsid
Albertadromeus^[13]	A. syntarsus		Upper		A thescelosaurid
Anchiceratops	Indeterminate				A ceratopsid
Brachylophosaurus	B. canadensis		Upper	Skull And partial skeleton	A hadrosaurid
Chasmosaurus	C. brevirostris				Junior synonym of C. russelli
	C. russelli		Upper		A ceratopsid, also found in the Dinosaur Park Formation
Coronosaurus	C. brinkmani		Upper		A ceratopsid
Corythosaurus	C. casuarius		Upper		A hadrosaurid, also found in the Dinosaur Park Formation
Foraminacephale	F. brevis		Also known from the Dinosaur Park Formation^[14]		A pachycephalosaurid, once thought to be a species of Stegoceras
Gremlin^[15]	G. slobodorum		Lower	A right frontal	A leptoceratopsid
Hanssuesia	H. sternbergi		Upper, also present in the Dinosaur Park Formation and Judith River Formation	skull dome	A pachycephalosaurid, potentially synonymous with Stegoceras validum^[16]
Maiasaura	M. peeblesorum		Upper		A hadrosaurid, also known from the Two Medicine Formation.^[17]
Parasaurolophus	P. walkeri		Upper		A hadrosaurid, also found in the Dinosaur Park Formation
Scolosaurus	S. cutleri		Upper		An ankylosaurid, may actually be from the Dinosaur Park Formation
Wendiceratops	W. pinhornensis		Lower	Partial Skeleton And Partial Skull	A centrosaurine
An unnamed orodromine	Unnamed		Upper		An orodromine distinct from Albertadromeus. Closer to Oryctodromeus than to Albertadromeus, Orodromeus, and Zephyrosaurus.^[18]

See also

• List of fossil sites (with link directory)
• List of dinosaur-bearing rock formations

References

Bibliography

• D.A. Eberth. 1996. Origin and significance of mud-filled incised valleys (Upper Cretaceous) in southern Alberta, Canada. Sedimentology 43:459–477
• Ryan, M. J., and Russell, A. P., 2001. Dinosaurs of Alberta (exclusive of Aves): In: Mesozoic Vertebrate Life, edited by Tanke, D. H., and Carpenter, K., Indiana University Press, pp. 279–297

Notes and References

1. Russell, L.S. and Landes, R.W., 1940. Geology of the southern Alberta Plains; Geological Survey of Canada, Memoir 221.
2. Web site: Oldman Formation. https://archive.today/20130222074639/http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:011229. dead. 2013-02-22. Lexicon of Canadian Geological Units. 2009-02-06.
3. Eberth, D.A. and Hamblin A.P. 1993. Tectonic, stratigraphic, and sedimentologic significance of a regional discontinuity in the upper Judith River Group (Belly River wedge) of southern Alberta, Saskatchewan, and northern Montana. Canadian Journal of Earth Sciences 30: 174-200.
4. Eberth, D.A. 2005. The geology. In: Currie, P.J., and Koppelhus, E.B. (eds), Dinosaur Provincial Park: A Spectacular Ancient Ecosystem Revealed. Indiana University Press: Bloomington and Indianapolis, p. 54-82. .
5. Arbour, V.M.. Victoria Arbour. Burns, M. E.. Sissons, R. L.. 2009. A redescription of the ankylosaurid dinosaur Dyoplosaurus acutosquameus Parks, 1924 (Ornithischia: Ankylosauria) and a revision of the genus. Journal of Vertebrate Paleontology. 29. 4. 1117–1135. 10.1671/039.029.0405. 2009JVPal..29.1117A .
6. Lerbekmo, J.F. 1989. The position of the 33-33r (Campanian) polarity chron boundary in southeastern Alberta. Bulletin of Canadian Petroleum Geology 37: 43-47.
7. Weishampel, D.B., Barrett, P.M., Coria, R.A., Le Loueff, J., Xu X., Zhao X., Sahni, A., Gomani, E.M.P., & Noto, C.N. 2004. Dinosaur distribution. In: Weishampel, D.B., Dodson, P., & Osmólska, H. (Eds.). The Dinosauria (2nd Edition). Berkeley: University of California Press. Pp. 517-606.
8. Miyashita. Tetsuto. Currie. Philip. Paulina-Carabajal. Ariana. 2013. A new species of Daspletosaurus (Theropoda: Tyrannosauridae) from the Campanian of southern Alberta represented by a growth series of well-preserved skulls and skeletons. Journal of Vertebrate Paleontology. 33. Supplement 1. 178.
9. Longrich. N.R.. Currie. P.J.. 2009. A microraptorine (Dinosauria–Dromaeosauridae) from the Late Cretaceous of North America. Proceedings of the National Academy of Sciences. 106. 13. 5002–5007. 10.1073/pnas.0811664106. free . 19289829 . 2664043. 2009PNAS..106.5002L .
10. Hartman . Scott . Mortimer . Mickey . Wahl . William R. . Lomax . Dean R. . Lippincott . Jessica . Lovelace . David M. . 2019-07-10 . A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight . PeerJ . en . 7 . e7247 . 10.7717/peerj.7247 . 2167-8359 . 6626525 . 31333906 . free .
11. Zelenitsky. Darla K.. Hills. L.V.. An egg clutch of Prismatoolithus levis oosp. nov. from the Oldman Formation (Upper Cretaceous), Devil's Coulee, southern Alberta. Canadian Journal of Earth Sciences. 1996. 33. 8. 1127–1131. 10.1139/e96-085. 1996CaJES..33.1127Z .
12. Claessens . L. . Loewen . Mark A. . 2015 . A redescription of Ornithomimus velox Marsh, 1890 (Dinosauria, Theropoda) . Journal of Vertebrate Paleontology . 36. e1034593. 10.1080/02724634.2015.1034593 .
13. Brown . C. M. . Evans . D. C. . Ryan . M. J. . Russell . A. P. . New data on the diversity and abundance of small-bodied ornithopods (Dinosauria, Ornithischia) from the Belly River Group (Campanian) of Alberta . 10.1080/02724634.2013.746229 . Journal of Vertebrate Paleontology . 33 . 3 . 495 . 2013 . 2013JVPal..33..495B .
14. Book: Sullivan . R.M. . 2006 . A taxonomic review of the Pachycephalosauridae (Dinosauria: Ornithischia) . Lucas . S.G. . Sullivan . R.M. . Late Cretaceous vertebrates from the Western Interior . 35 . 347–365 . New Mexico Museum of Natural History and Science Bulletin . http://www.robertmsullivanphd.com/uploads/130_Sullivan__2006__-Pachycephalosauridae.pdf.
15. Book: Ryan . M.J. . Micucci . L. . Rizo . H. . Sullivan . C. . Lee . Y.-N. . Evans . D.C. . 2023 . A New Late Cretaceous leptoceratopsid (Dinosauria: Ceratopsia) from the Oldman Formation (Campanian) of Alberta, Canada . Lee . Y.-N. . Windows into Sauropsid and Synapsid Evolution: Essays in Honor of Prof. Louis L. Jacobs . Dinosaur Science Center Press . Seoul . 978-89-5708-358-1 . 151–165.
16. Dyer . Aaron D. . Powers . Mark J. . Currie . Philip J. . 2023 . Problematic putative pachycephalosaurids: Synchrotron µCT imaging shines new light on the anatomy and taxonomic validity of Gravitholus albertae from the Belly River Group (Campanian) of Alberta, Canada . Vertebrate Anatomy Morphology Palaeontology . en . 10 . 1 . 65–110 . 10.18435/vamp29388 . 2292-1389. free .
17. McFeeters . Bradley D. . Evans . David C. . Ryan . Michael J. . Maddin . Hillary C. . First occurrence of Maiasaura (Dinosauria, Hadrosauridae) from the Upper Cretaceous Oldman Formation of southern Alberta, Canada . Canadian Journal of Earth Sciences . 22 December 2020 . 58 . 3 . 286–296 . 10.1139/cjes-2019-0207 .
18. Brown . C. M. . Evans . D. C. . Ryan . M. J. . Russell . A. P. . New data on the diversity and abundance of small-bodied ornithopods (Dinosauria, Ornithischia) from the Belly River Group (Campanian) of Alberta . 10.1080/02724634.2013.746229 . Journal of Vertebrate Paleontology . 33 . 3 . 495 . 2013 . 2013JVPal..33..495B .