Dunvegan Formation
{{Short description|Stratigraphical unit in the Western Canadian Sedimentary Basin}}
{{Infobox Rockunit
| name = Dunvegan Formation
| image = Dunvegan Formation.png
| caption = An outcrop of the Dunvegan Formation along the Pine River, which is the type locality for CMN 59667, an unnamed ankylosaur species.
| type = Geological formation
| age = Cenomanian
~{{fossil range|99|94}}
| period = Cenomanian
| prilithology = Sandstone
| otherlithology = Shale
| namedfor = Dunvegan, Alberta
| namedby = George Mercer Dawson
| year_ts = 1881
| region = Northeast {{flag|British Columbia}}
Northwest {{flag|Alberta}}
| country = {{flag|Canada}}
| coordinates = {{coord|55.92043|N|118.63203|W|name=Dunvegan Formation|display=inline,title}}
| unitof =
| subunits =
| underlies = Smoky Group
| overlies = Fort St. John Group (Shaftesbury Formation)
| thickness = up to {{convert|380|ft|m|-1}}{{Cite web |url=http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:004324 |title=Dunvegan Formation |author=Lexicon of Canadian Geologic Units |accessdate=2009-02-10 |url-status=dead |archiveurl=https://archive.today/20130221071748/http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl?00053:004324 |archivedate=2013-02-21 }}
| extent =
| area =
| map = {{Location map+ | Canada
| relief = 1
| width = 300
| float = center
| places =
{{Location map~ | Canada
| lat_deg = 55.9
| lon_deg = -118.6
| mark = Lightgreen pog.svg
| marksize = 12
}}
}}
| map_caption =
}}
The Dunvegan Formation is a stratigraphical unit of Cenomanian age in the Western Canadian Sedimentary Basin.
It takes the name from the settlement of Dunvegan, Alberta, and was first described in an outcrop on Peace River near Dunvegan by George Mercer Dawson in 1881.Dawson, G.M., 1881. Report on the exploration from Port Simpson on the Pacific Coast to Edmonton on the Saskatchewan River, Embracing a portion of the northern part of British Columbia and the Peace River Country, with Maps 150 and 152; Geological Survey of Canada, Report of Progress 1879-1880, Part B, p. 1-77.
Fossils
Nodosaur footprints attributed to Tetrapodosaurus borealis, ornithopod footprints, and theropod footprints attributed to Columbosauripus ungulatus and Ardeipeda sp. are common within the Dunvegan Formation.{{Cite journal |last1=Plint |first1=A. Guy |last2=Helm |first2=Charles W. |last3=Lockley |first3=Martin G. |date=2022-03-03 |title=Crocodylian and dinosaur trace fossil assemblages from crevasse splay/levee and floodplain lake environments: middle Cenomanian Dunvegan Formation, northeast British Columbia, Canada |url=http://dx.doi.org/10.1080/08912963.2022.2043294 |journal=Historical Biology |volume=35 |issue=3 |pages=403–429 |doi=10.1080/08912963.2022.2043294 |issn=0891-2963}}{{Cite journal |last=Storer |first=John E. |date=1975-10-01 |title=Dinosaur Tracks, Columbosauripus ungulatus (Saurischia: Coelurosauria), from the Dunvegan Formation (Cenomanian) of Northeastern British Columbia |url=http://dx.doi.org/10.1139/e75-160 |journal=Canadian Journal of Earth Sciences |volume=12 |issue=10 |pages=1805–1807 |doi=10.1139/e75-160 |bibcode=1975CaJES..12.1805S |issn=0008-4077}}{{Cite journal |last=Lockley |first=Martin G. |last2=Plint |first2=A. Guy |last3=Helm |first3=Charles W. |title=Heron-like tracks from the Dunvegan Formation (Cenomanian), British Columbia: evidence for convergence in avian foot morphology |url=https://www.tandfonline.com/doi/full/10.1080/08912963.2025.2477201 |journal=Historical Biology |volume=0 |issue=0 |pages=1–14 |doi=10.1080/08912963.2025.2477201 |issn=0891-2963}} Dinosaur body fossils are also known from the formation, including:
- Specimen HH 2017.010.002, an ankylosaur femur discovered along the Murray River in 1993 and described in 2024.{{cite journal|last1= Cross|first1= E.C|last2=Arbour|first2= V.M|year= 2024|title= An ankylosaur femur from the mid-Cretaceous of the Peace Region of northeastern British Columbia|journal= Canadian Journal of Earth Sciences|doi=10.1139/cjes-2023-0118|s2cid= 267961368}}
- Specimen CMN 59667, a block containing two vertebrae and two ribs from an ankylosaur that was discovered along the Pine River in 1930 and was described in 2020.{{Cite journal |last1=Arbour |first1=Victoria M. |last2=Larson |first2=Derek |last3=Vavrek |first3=Matthew |last4=Buckley |first4=Lisa |last5=Evans |first5=David |date=2020 |title=An ankylosaurian dinosaur from the Cenomanian Dunvegan Formation of northeastern British Columbia, Canada |url=https://fr.copernicus.org/articles/23/179/2020/ |journal=Fossil Record |language=en |volume=23 |issue=2 |pages=179–189 |doi=10.5194/fr-23-179-2020 |doi-access=free |bibcode=2020FossR..23..179A |issn=2193-0074}}
- Other ankylosaur remains including osteoderms from Alberta.
Bony fish,{{Cite journal |last1=Hay |first1=Michael J |last2=Cumbaa |first2=Stephen L |last3=Murray |first3=Alison M |last4=Plint |first4=A Guy |date=2007-06-29 |title=A new paraclupeid fish (Clupeomorpha, Ellimmichthyiformes) from a muddy marine pro-delta environment: middle Cenomanian Dunvegan Formation, Alberta, Canada |url=http://dx.doi.org/10.1139/e07-002 |journal=Canadian Journal of Earth Sciences |volume=44 |issue=6 |pages=775–790 |doi=10.1139/e07-002 |bibcode=2007CaJES..44..775H |issn=0008-4077}}{{Cite journal |last1=Vavrek |first1=Matthew J. |last2=Murray |first2=Alison M. |last3=Bell |first3=Phil R. |date=2014 |title=An early Late Cretaceous (Cenomanian) sturgeon (Acipenseriformes) from the Dunvegan Formation, northwestern Alberta, Canada |url=http://dx.doi.org/10.1139/cjes-2014-0052 |journal=Canadian Journal of Earth Sciences |volume=51 |issue=7 |pages=677–681 |doi=10.1139/cjes-2014-0052 |bibcode=2014CaJES..51..677V |issn=0008-4077}} sharks,{{Cite journal |last1=Cook |first1=Todd D. |last2=Wilson |first2=Mark V.H. |last3=Murray |first3=Alison M. |date=2008 |title=A middle Cenomanian euselachian assemblage from the Dunvegan Formation of northwestern Alberta |url=http://dx.doi.org/10.1139/e08-064 |journal=Canadian Journal of Earth Sciences |volume=45 |issue=10 |pages=1185–1197 |doi=10.1139/e08-064 |bibcode=2008CaJES..45.1185C |issn=0008-4077}} crocodylian footprints, and Metasequoia leaves have also been found in the Dunvegan Formation.
Lithology
The Dunvegan Formation is composed of marine, and deltaic sandstone with thin shale interbeds in the Peace River Country. East of Dunvegan, Alberta it is of marine origin, and in its western reaches in British Columbia it was deposited in a continental facies, where the sandstone becomes more conglomeratic. During Dunvegan time, a brackish water environment was present in the Wapiti River area and south of Grande Prairie, where the formation is porous.
Hydrocarbon production
The Dunvegan Formation had an initial established recoverable oil reserve of 9.9 million m³, with 3.1 million m³ already produced as of 2008.{{Cite web|url=http://www.ags.gov.ab.ca/publications/wcsb_atlas/A_CH32/TB32_01.html|title=The Geological Atlas of the Western Canada Sedimentary Basin - Summary of oil reserves and production data|author=Mossop, G.D. and Shetsen, I - Canadian Society of Petroleum Geologists|year=1994|accessdate=2009-03-06|url-status=dead|archiveurl=https://web.archive.org/web/20090328192518/http://www.ags.gov.ab.ca/publications/wcsb_atlas/A_CH32/TB32_01.html|archivedate=2009-03-28}} Gas reserves totaled 18.7 million m³, with 4.5 million m³ already produced.{{Cite web|url=http://www.ags.gov.ab.ca/publications/wcsb_atlas/A_CH32/TB32_02.html|title=The Geological Atlas of the Western Canada Sedimentary Basin - Summary of gas reserves and production data|author=Mossop, G.D. and Shetsen, I - Canadian Society of Petroleum Geologists|year=1994|accessdate=2009-03-06}}
Distribution
The Dunvegan Formation is {{convert|180|ft|m|-1}} thick in its type locality in Peace River Country and up to {{convert|380|ft|m|-1}} in the sub-surface of the Canadian Rockies foothills. It occurs south of Fort Nelson and the Liard River in north-east British Columbia, thins out south of the Peace River Country. South of the Athabasca River, the Dunvegan grades laterally into the Blackstone Formation.
The Dunvegan Formation is exposed in outcrop along and near the Peace River east of the foothills, in the Peace River Country and the Chinchaga area, as well as patches in north-western Alberta and south of the Caribou Mountains.
Relationship to other units
The Dunvegan Formation is conformably overlain by marine shales of the Kaskapau Formation in the Peace River Country and overlies conformably and transitionally the shale of the Fort St. John Group. The relationship between the Dunvegan and the overlying/underlying units is diachronous and the boundaries of the Dunvegan are placed at the first and last appearances of sandstone within the shale-dominated succession.{{cite journal|last1=Plint|first1=A. Guy|title=Sequence Stratigraphy and Paleogeography of a Cenomanian Deltaic Complex: the Dunvegan and Lower Kaskapau Formations in Subsurface and Outcrop, Alberta and British Columbia, Canada|journal=Bulletin of Canadian Petroleum Geology|date=March 2000|volume=48|issue=1|pages=43–79|doi=10.2113/48.1.43 |url=http://archives.datapages.com/data/cspg/data/048/048001/0043.htm}}
References
{{reflist}}
{{Western Canadian Sedimentary Basin|Northwest_Plains=yes|Fort_Nelson=yes}}
Category:Geologic formations of Alberta
Category:Geologic formations of British Columbia
Category:Upper Cretaceous Series of North America
Category:Sandstone formations of Canada