Milk River Formation

Last updated
Milk River Formation
Stratigraphic range:
Santonian-Campanian
~84.1–83.6  Ma
O
S
D
C
P
T
J
K
Pg
N
Milkriverpan.jpg
Outcrops along the Milk River
Type Geological formation
Unit of Montana Group
Sub-unitsDeadhorse Coulee Member
Virgelle Member
Telegraph Creek Member
Underlies Pakowki Formation
Overlies Colorado Group
Thicknessup to 113 metres (370 ft) [1]
Lithology
Primary Sandstone
Other Siltstone, shale, coal
Location
Region Alberta
Country Canada
Type section
Named for Milk River
Named byD.B. Dowling, 1916 [2]

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]

Contents

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 Milk River Formation.jpg
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.

Cartilaginous fishes reported from the Milk River Formation
GenusSpeciesLocationStratigraphic positionMaterialNotes

Lonchidion

Indeterminate

Hybodontoidea

Myledaphus

M. bipartitus

Rhinobatoidei

Bony fishes

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

Bony fishes reported from the Milk River Formation
GenusSpeciesLocationStratigraphic positionMaterialNotesImages

Belonostomus

Indeterminate

Aspidorhynchidae

Belonostomus Belonostomus sp cm4776a.jpg
Belonostomus
Lepisosteus Longnose gar.png
Lepisosteus

Lepisosteus

L. occidentalis

Lepisosteidae

Palaeolabrus

Indeterminate

Lepisosteidae

Amphibians

Amphibians reported from the Milk River Formation
GenusSpeciesLocationStratigraphic positionMaterialNotesImages

Albanerpeton

A. galaktion

Albanerpetontidae

Albanerpeton Albanerpeton BW.jpg
Albanerpeton

A. nexuosus

Albanerpetontidae

Opisthotriton

Indeterminate

Batrachosauroididae

Squamates

Indeterminate Anguidae and Xenosauridae genera and species.

Squamates reported from the Milk River Formation
GenusSpeciesLocationStratigraphic positionMaterialNotes

Aocnodromeus

A. corrugatus

Scincidae

Chamops

Indeterminate

Teiidae

Coniophis

cf. C. precedens

Aniliidae

Cnephasaurus

C. locustivorus

Iguanidae

Glyptogenys

G. ornata

Teiidae

Parasaniwa ?

Indeterminate

Necrosauridae

Penemabuya

P. antecessor

Scincidae

Sphenosiagon

S. simplex

Teiidae

Turtles

Indeterminate Solemydidae and Trionychidae genera and species.

Turtles reported from the Milk River Formation
GenusSpeciesLocationStratigraphic positionMaterialNotes

Adocus

Indeterminate

Adocidae

Basilemys

Indeterminate

Nanhsiungchelyidae

? Boremys

Indeterminate

Baenidae

? Compsemys

Indeterminate

Family indeterminant

Neurankylus

N. lithographicus

Baenidae

Plesiobaena

Indeterminate

Baenidae

Crocodilians

Crocodilians reported from the Milk River Formation
GenusSpeciesLocationStratigraphic positionMaterialNotes

Gilchristosuchus

G. palatinus

Dinosaurs

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

Color key
Taxon Reclassified taxonTaxon falsely reported as presentDubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.
Dinosaurs reported from the Milk River Formation
GenusSpeciesLocationStratigraphic positionMaterialNotesImages

Lithostrotia [6]

Indeterminate

Caudal Centrum

An indeterminate Titanosaurian sauropod, the first from Canada. Cited to be similar to caudals referred to Alamosaurus . [6]

Acrotholus [7]

A. audeti

Skull domes

A pachycephalosaur

Acrotholus Acrotholus NT.jpg
Acrotholus
Saurornitholestes Saurornitholestes digging Burrows wahweap.jpg
Saurornitholestes

Brachyceratops [8]

Indeterminate [8]

Continuoolithus [9] cf. C. canadensisOne eggshell fragmentLaid by a theropod.

Gryphoceratops [10]

G. morrisoni

Partial right dentary

A leptoceratopsid

Kritosaurus [11]

Indeterminate

Palaeoscincus [12]

Indeterminate

cf. Paronychodon [13]

cf. P. lacustris [13]

Theropoda incertae sedis

Porituberoolithus [9] cf. P. warnerensisOne eggshell fragmentLaid by a theropod
Prismatoolithus [9] Indeterminate6 isolated eggshell fragmentsLaid by a theropod.

cf. Richardoestesia [13]

cf. R. gilmorei [13]

Maniraptora incertae sedis

cf. R. isosceles

Maniraptora incertae sedis

Saurornitholestes [14]

S. langstoni [14]

Dromaeosauridae

Spheroolithus [9] cf. S. choteauensis313 isolated eggshell fragmentsLaid by an ornithopod.
Triprismatoolithus [9] Indeterminate60 isolated eggshell fragmentsLaid by a bird or theropod.

Mammals

Other mammals

Other Mammals reported from the Milk River Formation
GenusSpeciesLocationStratigraphic positionMaterialNotes

Alticonodon

A. lindoei

Triconodontidae

Cimexomys

C. antiquus

Neoplagiaulacidae?

C. magister

Neoplagiaulacidae?

Cimolodon

C. electus

Cimolodontidae

C. similis

Cimolodontidae

Cimolomys

Indeterminate

Cimolomyidae

Ectypodus

cf. E. powelli

Meniscoessus

M. ferox

Cimolomyidae

Mesodma

Mesodma senecta

Indeterminate

Mictodon

Mictodon simpsoni

Tinodontidae

Paracimexomys

P. magister

Family indeterminent

Paranyctoides

Paranyctoides maleficus

Nyctitheriidae

Picopsis

P. pattersoni

Picopsidae

Indeterminate

Picopsidae

Potamotelses

P. aquilensis

Potamotelsidae

Symmetrodontoides

S. canadensis

Spalacotheriidae

Viridomys

V. orbatus

Neoplagiaulacidae?

Didelphomorphs

Didelphomorphs reported from the Milk River Formation
GenusSpeciesLocationStratigraphic positionMaterialNotesImages

Albertatherium

A. primus

Peradectidae

Alphadon Alphadon sp. - MUSE.jpg
Alphadon
Didelphodon Didelphodon NT small.jpg
Didelphodon

A. secundus

Peradectidae

Alphadon

A. halleyi

Peradectidae

Indeterminate

Peradectidae

Aquiladelphis

A. incus

Aquiladelphidae

A. minor

Aquiladelphidae

Didelphodon

Indeterminate

Stagodontidae

Eodelphis

Indeterminate

Stagodontidae

Iqualadelphis

I. lactea

Pediomyidae

Pediomys

cf. P. clemensi

Pediomyidae

P. exiguus

Pediomyidae

P. florencae

Pediomyidae

Protalphadon

P. creber

Peradectidae

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. 1 2 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. 1 2 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. 1 2 3 4 5 6 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. 1 2 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. 1 2 Listed as "cf. Brachyceratops sp." in "1.4 Alberta, Canada; 5. Milk River Formation," in Weishampel, et al. (2004). Page 576.
  9. 1 2 3 4 5 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. 1 2 3 4 "1.4 Alberta, Canada; 5. Milk River Formation," in Weishampel, et al. (2004). Page 576.
  14. 1 2 Listed as "cf. Saurornitholestes langstoni" in "1.4 Alberta, Canada; 5. Milk River Formation," in Weishampel, et al. (2004). Page 576.

References