Milk River Formation
Template:Infobox Rockunit 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.[1]
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.[2]
Stratigraphy and lithology
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.[3][2]
In Alberta it is subdivided into the following three members:[3]
- Telegraph Creek Member, at the base, consists primarily of mudstones and shales deposited in offshore marine settings. It has produced the ammonite index fossil Desmoscaphites bassleri, which indicates an age of ~84. Ma.[3][1]
- Virgelle Member, the central member, is a sequence of massive, cliff-forming, yellow to white sandstones that were deposited in shoreface and tidal channel environments. It can be seen at Writing-on-Stone Provincial Park.[3]
- Deadhorse Coulee Member, at the top, consists of predominantly nonmarine shales, siltstones, sandstones, and coal beds that were deposited in rivers, floodplains and swamps.[3] Most of the vertebrate fossils have come from this member.[3]
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.
| Cartilaginous fishes reported from the Milk River Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | |
|
Indeterminate |
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|
M. bipartitus |
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Bony fishes
Remains of Acipenseridae, Amiidae, Esocidae, indeterminate genera and species.
| Bony fishes reported from the Milk River Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
|
Indeterminate |
| |||||
|
L. occidentalis |
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|
Indeterminate |
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Amphibians
| Amphibians reported from the Milk River Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
|
A. galaktion |
| |||||
|
A. nexuosus |
||||||
|
Indeterminate |
||||||
Squamates
Indeterminate Anguidae and Xenosauridae genera and species.
| Squamates reported from the Milk River Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | |
|
A. corrugatus |
||||||
|
Indeterminate |
||||||
|
cf. C. precedens |
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|
C. locustivorus |
||||||
|
G. ornata |
||||||
|
Indeterminate |
||||||
|
P. antecessor |
||||||
|
S. simplex |
||||||
Turtles
Indeterminate Solemydidae and Trionychidae genera and species.
| Turtles reported from the Milk River Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | |
|
Indeterminate |
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|
Indeterminate |
||||||
|
Indeterminate |
||||||
|
Indeterminate |
Family indeterminant | |||||
|
N. lithographicus |
||||||
|
Indeterminate |
||||||
Crocodilians
| Crocodilians reported from the Milk River Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | |
|
G. palatinus |
||||||
Dinosaurs
Indeterminate Ankylosauridae, Aves, Ceratopsidae, Dromaeosauridae, Hadrosauridae, Nodosauridae, Ornithomimidae, Pachycephalosauridae, Protoceratopsidae, Thescelosauridae, and Tyrannosauridae genera and species. Template:Paleobiota-key-compact
| Dinosaurs reported from the Milk River Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
|
Indeterminate |
Caudal Centrum |
An indeterminate Titanosaurian sauropod, the first from Canada. Cited to be similar to caudals referred to Alamosaurus.[4] |
||||
|
A. audeti |
Skull domes |
| ||||
|
Indeterminate[6] |
||||||
| Continuoolithus[7] | cf. C. canadensis | One eggshell fragment | Laid by a theropod. | |||
|
G. morrisoni |
Partial right dentary |
|||||
|
Indeterminate |
||||||
|
Indeterminate |
||||||
|
cf. Paronychodon[11] |
cf. P. lacustris[11] |
Theropoda incertae sedis | ||||
| Porituberoolithus[7] | cf. P. warnerensis | One eggshell fragment | Laid by a theropod | |||
| Prismatoolithus[7] | Indeterminate | 6 isolated eggshell fragments | Laid by a theropod. | |||
|
cf. R. gilmorei[11] |
Maniraptora incertae sedis | |||||
|
cf. R. isosceles |
Maniraptora incertae sedis | |||||
|
S. langstoni[12] |
||||||
| Spheroolithus[7] | cf. S. choteauensis | 313 isolated eggshell fragments | Laid by an ornithopod. | |||
| Triprismatoolithus[7] | Indeterminate | 60 isolated eggshell fragments | Laid by a bird or theropod. | |||
Mammals
Other mammals
| Other Mammals reported from the Milk River Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | |
|
A. lindoei |
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|
C. antiquus |
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|
C. magister |
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|
C. electus |
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|
C. similis |
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|
Indeterminate |
||||||
|
cf. E. powelli |
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|
M. ferox |
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|
Mesodma senecta |
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|
Indeterminate |
||||||
|
P. magister |
Family indeterminent | |||||
|
Paranyctoides maleficus |
||||||
|
P. pattersoni |
||||||
|
Indeterminate |
||||||
|
P. aquilensis |
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|
S. canadensis |
||||||
|
V. orbatus |
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Didelphomorphs
| Didelphomorphs reported from the Milk River Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
|
A. primus |
| |||||
|
A. secundus |
||||||
|
A. halleyi |
||||||
|
Indeterminate |
||||||
|
A. incus |
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|
A. minor |
||||||
|
Indeterminate |
||||||
|
Indeterminate |
||||||
|
I. lactea |
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|
cf. P. clemensi |
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|
P. exiguus |
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|
P. florencae |
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|
P. creber |
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See also
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Footnotes
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- ↑ a b Script error: No such module "Citation/CS1".
- ↑ 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.
- ↑ 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.
- ↑ a b Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
- ↑ a b Listed as "cf. Brachyceratops sp." in "1.4 Alberta, Canada; 5. Milk River Formation," in Weishampel, et al. (2004). Page 576.
- ↑ a b c d e Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
- ↑ Listed as "cf. Kritosaurus sp." in "1.4 Alberta, Canada; 5. Milk River Formation," in Weishampel, et al. (2004). Page 576.
- ↑ Listed as "cf. Kritosaurus" in "1.4 Alberta, Canada; 5. Milk River Formation," in Weishampel, et al. (2004). Page 576.
- ↑ a b c d "1.4 Alberta, Canada; 5. Milk River Formation," in Weishampel, et al. (2004). Page 576.
- ↑ a b Listed as "cf. Saurornitholestes langstoni" in "1.4 Alberta, Canada; 5. Milk River Formation," in Weishampel, et al. (2004). Page 576.
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References
- Brinkman, D. 2003. A review of nonmarine turtlesfrom the Late Cretaceous of Alberta. Canadian Journal of Earth Sciences 40:557-571.
- Gao, K., Fox, R.C. 1996. Taxonomy and evolution of late Cretaceous lizards (Reptilia: Squamata) from Western Canada. Bulletin of the Carnegie Museum 33: 1-107.
- Hilton, E.J. And Grande, L. 2006. Review of the fossil record of sturgeons, family Acipenseridae (Actinopterygii: Acipenseriformes), from North America. Journal of Paleontology 80: 672-683.
- Larson, D.W. 2008. Diversity and variation of theropod dinosaur teeth from the uppermost Santonian Milk River Formation (Upper Cretaceous), Alberta: a quantitative method supporting identification of the oldest dinosaur tooth assemblage in Canada. Canadian Journal of Earth Sciences 45: 1455-1468.
- Payenberg, T.H.D., 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 Eagle Formation in Montana utilising stratigraphy, U–Pb geochronology, and palynology. Canadian Journal of Earth Sciences 39:1553-1577.
- Sullivan, R.M. 2003. Revision of the dinosaur Stegoceras Lambe (Ornithischia, Pachycephalosauridae). Journal of Vertebrate Paleontology 23: 181-207.
- University of Alberta Museum https://web.archive.org/web/20090815182206/http://www.museums.ualberta.ca/dig/search/vpaleo/index.html