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Milk River Formation

The Milk River Formation is a sandstone-dominated stratigraphic unit of the Western Canada Sedimentary Basin in southern Alberta, Canada. It was deposited in near-shore to coastal environments during Late Cretaceous (late Santonian to early Campanian) time. Based on uranium-lead dating, palynology and stratigraphic relationships, deposition occurred between ~84.1 and 83.6 Ma.[3]

The sandstones of the Virgelle Member in the centre of the formation are well-exposed at Writing-on-Stone Provincial Park in southwestern Alberta, where they bear petroglyphs carved into them by First Nations people.

The formation is fossiliferous and has yielded an extensive vertebrate fauna (see Tables below), as well as fossil ammonites. In some areas it hosts shallow natural gas reservoirs.[4]

Stratigraphy and lithology

Sandstones of the Milk River Formation at Writing-on-Stone Provincial Park

The Milk River Formation is an eastward-thinning wedge of clastic sediments that was deposited along the western margin of the Western Interior Seaway during Late Cretaceous (late Santonian to early Campanian) time. It is age-equivalent to the marine shales of the Lea Park Formation in southeastern Alberta, and to the Eagle and Telegraph Creek Formations of north-central Montana.[5][4]

In Alberta it is subdivided into the following three members:[5]

Vertebrates

(references: Brinkman 2003; Gao and Fox 1995; Hilton and Grande 2006; Larson 2008; Sullivan 2003; University of Alberta webpage)

Cartilaginous fishes

Remains of an indeterminate lamnid genus and species are present.

Bony fishes

Remains of Acipenseridae, Amiidae, Esocidae, indeterminate genera and species.

Amphibians

Squamates

Indeterminate Anguidae and Xenosauridae genera and species.

Turtles

Indeterminate Solemydidae and Trionychidae genera and species.

Crocodilians

Dinosaurs

Indeterminate Ankylosauridae, Aves, Ceratopsidae, Dromaeosauridae, Hadrosauridae, Nodosauridae, Ornithomimidae, Pachycephalosauridae, Protoceratopsidae, Thescelosauridae, and Tyrannosauridae genera and species.

Mammals

Other mammals

Didelphomorphs

See also

Footnotes

  1. ^ 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.
  2. ^ Dowling, D.B., 1916. Water Supply, Southeastern Alberta (Contains Geological Map 1604); Geological Survey of Canada, Summary Report 1915, pp. 102-110.
  3. ^ a b Fowler, Denver Warwick (2017-11-22). "Revised geochronology, correlation, and dinosaur stratigraphic ranges of the Santonian-Maastrichtian (Late Cretaceous) formations of the Western Interior of North America". PLOS ONE. 12 (11): e0188426. doi:10.1371/journal.pone.0188426. ISSN 1932-6203. PMC 5699823. PMID 29166406.
  4. ^ a b Payenberg, T.D.H., Braman, D.R. and Miall, A.D. 2003. Depositional environments and stratigraphic architecture of the Late Cretaceous and Eagle formations, southern Alberta and north-central Montana: Relationships to shallow gas. Bulletin of Canadian Petroleum Geology, vol. 51, no. 2, p. 155-176.
  5. ^ a b c d e f Payenberg, T.D.H., Braman, D.R., Davis, D.W. and Miall, A.D. 2002. Litho- and chronostratigraphic relationships of the Santonian-Campanian Milk River Formation in southern Alberta and the Eagle Formation in Montana utilising stratigraphy, U-Pb geochronology, and palynology, Canadian Journal of Earth Sciences, vol. 39, p. 1553-1577.
  6. ^ a b Evans, D. C.; Ryan, M. J. (2018). "The first occurrence of a sauropod body fossil in Canada, with implications for the "sauropod hiatus" in North America". Journal of Vertebrate Paleontology. 1: 207.
  7. ^ Evans, D. C.; Schott, R. K.; Larson, D. W.; Brown, C. M.; Ryan, M. J. (2013). "The oldest North American pachycephalosaurid and the hidden diversity of small-bodied ornithischian dinosaurs". Nature Communications. 4: 1828. Bibcode:2013NatCo...4.1828E. doi:10.1038/ncomms2749. PMID 23652016.
  8. ^ a b Listed as "cf. Brachyceratops sp." in "1.4 Alberta, Canada; 5. Milk River Formation," in Weishampel, et al. (2004). Page 576.
  9. ^ a b c d e Zelenitsky, Darla K.; Therrien, François; Tanaka, Kohei; Kobatashi, Yoshitsugu; DebBuhr, Christopher L. (2017). "Dinosaur eggshells from the Santonian Milk River Formation of Alberta, Canada". Cretaceous Research. 74: 181–187. doi:10.1016/j.cretres.2017.02.016.
  10. ^ Michael J. Ryan; David C. Evans; Philip J. Currie; Caleb M. Brown; Don Brinkman (2012). "New leptoceratopsids from the Upper Cretaceous of Alberta, Canada". Cretaceous Research. 35: 69–80. doi:10.1016/j.cretres.2011.11.018.
  11. ^ Listed as "cf. Kritosaurus sp." in "1.4 Alberta, Canada; 5. Milk River Formation," in Weishampel, et al. (2004). Page 576.
  12. ^ Listed as "cf. Kritosaurus" in "1.4 Alberta, Canada; 5. Milk River Formation," in Weishampel, et al. (2004). Page 576.
  13. ^ a b c d "1.4 Alberta, Canada; 5. Milk River Formation," in Weishampel, et al. (2004). Page 576.
  14. ^ a b Listed as "cf. Saurornitholestes langstoni" in "1.4 Alberta, Canada; 5. Milk River Formation," in Weishampel, et al. (2004). Page 576.

References