Wapiti Formation
{{Short description|Stratigraphic Unit in Canada}}
{{Infobox rockunit
| name = Wapiti Formation
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| type = Geological formation
| age = {{Fossil range|Campanian|Maastrichtian}}
| period =Campanian
| prilithology = Sandstone, siltstone, mudstone
| otherlithology = conglomerate, coal
| namedfor = Lower part of Wapiti River
| namedby = G.M. Dawson, 1881.Dawson, G.M. 1881. Report on the exploration from Simpson on the Pacific coast to Edmonton on the Saskatchewan River, embracing a portion of the northern part of Brisish Columbia and the Peace River country. Geological Survey of Canada, Report of Progress 1879-1880, Part B, p. 1-77.
| region ={{flag|Alberta}}
| country ={{flag|Canada}}
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The Wapiti Formation is a geological formation of the Western Canada Sedimentary Basin in northwestern Alberta, and northeastern British Columbia, Canada. Its deposition spanned the time interval from the lower Campanian through to the upper Maastrichtian, between approximately 80 and 68 Ma.{{Cite journal|last=Fowler|first=Denver Warwick|date=2017-11-22|title=Revised geochronology, correlation, and dinosaur stratigraphic ranges of the Santonian-Maastrichtian (Late Cretaceous) formations of the Western Interior of North America|journal=PLOS ONE|volume=12|issue=11|pages=e0188426|doi=10.1371/journal.pone.0188426|issn=1932-6203|pmc=5699823|pmid=29166406|bibcode=2017PLoSO..1288426F|doi-access=free}}{{Cite journal |last1=Fanti |first1=Federico |last2=Catuneanu |first2=Octavian |date=April 2009 |title=Stratigraphy of the Upper Cretaceous Wapiti Formation, west-central Alberta, Canada |url=https://cdnsciencepub.com/doi/10.1139/E09-020 |journal=Canadian Journal of Earth Sciences |volume=46 |issue=4 |pages=263–286 |doi=10.1139/E09-020 |bibcode=2009CaJES..46..263F |issn=0008-4077}} It was named by G.M. Dawson in 1881, presumably for exposures along the lower part of the Wapiti River and downstream along the Smoky River in Alberta.Glass, D.J. (editor) 1997. Lexicon of Canadian Stratigraphy, vol. 4, Western Canada including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba. Canadian Society of Petroleum Geologists, Calgary, 1423 p. on CD-ROM. {{ISBN|0-920230-23-7}}.
Dinosaur remains are among the fossils that have been recovered from the Cretaceous portion of the formation.Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Cretaceous, North America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 574-588. {{ISBN|0-520-24209-2}}.{{Cite web |last=Carter |first=Nicholas |date=2018-11-06 |title=Fossil Predators of the Wapiti Formation |url=https://dinomuseum.ca/2018/11/fossil_predators |access-date=2025-04-01 |website=Philip J. Currie Dinosaur Museum |language=en-CA}} The Wapiti Formation does not produce many fossils due to its limited surface exposure and accessibility, although two Pachyrhinosaurus bone beds have been productive.Ryan, M. J., and A. P. Russell, 2001, Dinosaurs of Alberta (exclusive of Aves), in: Mesozoic Vertebrate Life, edited by Tanke, D. H., and K. Carpenter, Indiana University Press, pp. 279–297 {{ISBN|978-0253339072}} Plant fossils and trace fossils have been unearthed here too.{{Cite journal |last1=Enriquez |first1=Nathan J. |last2=Campione |first2=Nicolás E. |last3=White |first3=Matt A. |last4=Fanti |first4=Federico |last5=Sissons |first5=Robin L. |last6=Sullivan |first6=Corwin |last7=Vavrek |first7=Matthew J. |last8=Bell |first8=Phil R. |date=2022-02-02 |title=The dinosaur tracks of Tyrants Aisle: An Upper Cretaceous ichnofauna from Unit 4 of the Wapiti Formation (upper Campanian), Alberta, Canada |journal=PLOS ONE |language=en |volume=17 |issue=2 |pages=e0262824 |doi=10.1371/journal.pone.0262824 |doi-access=free |issn=1932-6203 |pmc=8809565 |pmid=35108301|bibcode=2022PLoSO..1762824E }}{{Cite journal |last1=Kimitsuki |first1=Ryusuke |last2=Rodriguez |first2=Maria |last3=Sullivan |first3=Corwin |last4=Zonneveld |first4=John-Paul |last5=Sissons |first5=Robin |last6=Bell |first6=Phil R. |last7=Campione |first7=Nicolás E. |last8=Fanti |first8=Federico |last9=Gingras |first9=Murray K. |date=2024-10-01 |title=Enigmatic vertebrate swimming trace fossils from the Wapiti Formation, Alberta, Canada, and their implications for paleoenvironmental reconstruction |url=https://www.tandfonline.com/doi/full/10.1080/10420940.2024.2371971 |journal=Ichnos |volume=31 |issue=4 |pages=275–292 |doi=10.1080/10420940.2024.2371971 |bibcode=2024Ichno..31..275K |issn=1042-0940}}{{Cite web |last1=Fanti |first1=Federico |last2=Miyashita |first2=Tetsuto |date=May 2009 |title=A high latitude vertebrate fossil assemblage from the Late Cretaceous of west-central Alberta, Canada: evidence for dinosaur nesting and vertebrate latitudinal gradient |url=https://www.researchgate.net/publication/222698553 |archive-url=http://web.archive.org/web/20241201184127/https://www.researchgate.net/publication/222698553_A_high_latitude_vertebrate_fossil_assemblage_from_the_Late_Cretaceous_of_west-central_Alberta_Canada_evidence_for_dinosaur_nesting_and_vertebrate_latitudinal_gradient |archive-date=2024-12-01 |access-date=2025-04-01 |website=ResearchGate |language=en}}
Lithology
The Wapiti Formation consists of interbedded sandstones, siltstones, shales and mudstones, with thin conglomerates, coal seams and bentonite beds. The sandstones are typically thick, pale grey, crossbedded and bentonitic. The middle part contains less sandstones, more mudstones, and fewer and thinner coals. The upper part contains thicker lenticular sandstones and more coals.
Depositional environment
The Wapiti Formation was deposited in inland fluvial and floodplain environments, with local areas of lacustrine sediments.{{Cite web|url=http://www.ags.gov.ab.ca/publications/wcsb_atlas/a_ch24/ch_24.html|title=The Geological Atlas of the Western Canada Sedimentary Basin, Chapter 24: Upper Cretaceous and Tertiary strata of the Western Canada Sedimentary Basin|author=Mossop, G.D. and Shetsen, I., (compilers), Canadian Society of Petroleum Geologists|year=1994|access-date=2013-08-01|archive-date=2013-07-21|archive-url=https://web.archive.org/web/20130721174353/http://www.ags.gov.ab.ca/publications/wcsb_atlas/a_ch24/ch_24.html|url-status=dead}} The sandstones were deposited mainly in fluvial channel environments, with siltstones, carbonaceous shales and coals accumulating in overbank settings.
Thickness and Distribution
The Wapiti Formation rests conformably on the marine shales of the Smoky Group. It is more than {{convert|1300|m|ft|abbr=on}} thick in the foothills of the Canadian Rockies in the west, and it thins eastward to its erosional edge.{{Cite web|url=http://www.ags.gov.ab.ca/publications/pubs.aspx?series=map|title=Bedrock Geology of Alberta. Alberta Geological Survey, Map 600|author= Prior, G. J., Hathaway, B., Glombick, P.M., Pana, D.I., Banks, C.J., Hay, D.C., Schneider, C.L., Grobe, M., Elgr, R., and Weiss, J.A.|year=2013|access-date=2013-08-13}} It is correlative with the entire sequence of the Belly River Group, Bearpaw Formation, Edmonton Group and Scollard Formation in south-central Alberta. In most areas it is unconformably overlain by glacial and post-glacial sediments of Quaternary age, or exposed at surface. In a few upland areas it is unconformably overlain by Paleogene gravel deposits.
Vertebrate paleofauna
{{Paleobiota-key-compact}}
Indeterminate ankylosaurids, albertosaurines, pachycephalosaurids, ornithomimids, and saurolophines are known from Alberta.{{Cite journal|last1=Fanti|first1=Federico|last2=Miyashita|first2=Tetsuto|date=2009-05-01|title=A high latitude vertebrate fossil assemblage from the Late Cretaceous of west-central Alberta, Canada: evidence for dinosaur nesting and vertebrate latitudinal gradient|url=https://d1wqtxts1xzle7.cloudfront.net/37926836/Fanti_and_Miyashita_2009_3P.pdf?1434529043=&response-content-disposition=inline%3B+filename%3DA_high_latitude_vertebrate_fossil_assemb.pdf&Expires=1610476919&Signature=PL9mcbcge2rze6dr7mM9ftQKqoLB0sayaEc-PW~u2oSK3KyDpcB-9bB2FWYPYAAGoH8-Nl6pZEb3DzmuCe0aqK~w4mKXKA-vQbcZ-Yzppx2ivnBH1dAED8rLRvd5i1FhwPg24RqU80E3jHIQzDM-41KeykczY5cXFfA~3AThdggb9TpwUCWh8YonMaB5Cv0EpLkY-oJ0Wix6ivbwfYOgrwMq6UN0W0br~T7S9WCPeOmtOkVODHpw110V7-hvYCXYKyAAyzOaE8Bp4bKLrJDJSH99XZBOOzNh4B7wucD2IleL2S-l1PjYpvqVJs3jPjJDAsF3CxakJgO1w9i8T8M-FQ__&Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA|journal=Palaeogeography, Palaeoclimatology, Palaeoecology|language=en|volume=275|issue=1|pages=37–53|doi=10.1016/j.palaeo.2009.02.007|bibcode=2009PPP...275...37F|issn=0031-0182|via=}}{{dead link|date=May 2021|bot=medic}}{{cbignore|bot=medic}} Corythosaurus is also known from the formation.{{Cite journal|last1=Campione|first1=Nicolás|last2=Bell|first2=Phil R.|last3=Fanti|first3=Federico|last4=Sullivan|first4=Corvin|last5=Vavrek|first5=Matthew J.|date=2018|title=A JUVENILE CORYTHOSAUR (LAMBEOSAURINAE) FROM THE WAPITI FORMATION OF WESTERN ALBERTA, CANADA|url=http://vertpaleo.org/Annual-Meeting/Annual-Meeting-Home/SVP-2018-program-book-V4-FINAL-with-covers-9-24-18.aspx|journal=Journal of Vertebrate Paleontology, Program and Abstracts|volume=38}} A caenagnathid is in the process of being described.
See also
References
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{{coord missing|Alberta}}
Category:Geologic formations of North America
Category:Maastrichtian Stage of North America
Category:Cretaceous–Paleogene boundary
Category:Paleogene geology of Wyoming
Category:Fossiliferous stratigraphic units of North America