Frenchman Formation

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Template:Short description Template:Infobox Rockunit The Frenchman Formation is a stratigraphic unit of Late Cretaceous (late Maastrichtian) age in the Western Canada Sedimentary Basin. It is present in southern Saskatchewan and the Cypress Hills of southeastern Alberta. The formation was defined by G.M. Furnival in 1942[1] from observations of outcrops along the Frenchman River, between Ravenscrag and Highway 37. It contains the youngest of dinosaur genera, much like the Hell Creek Formation in the United States.

Lithology

The Frenchman Formation consists of olive-green to brown, fine- to coarse-grained, cross-bedded sandstone with interbedded claystone bands and minor beds and lenses of intraformational clay-clast conglomerate.[2] A conglomerate layer with well-rounded quartzite pebbles is present above the basal unconformity in some areas.[3]

Thickness and distribution

The Frenchman Formation is present in southwestern Saskatchewan and the Cypress Hills area of southeastern Alberta. Its maximum reported thickness is about 113 m.[3]

Age

The Frenchman Formation is of latest Maastrichtian age, and the top of the formation coincides with the Cretaceous-Paleogene boundary, as evidenced by biostratigraphic changes and, in some areas, the presence of the terminal Cretaceous iridium anomaly.[4]

Relationship to other units

Although some early workers included the Frenchman Formation in the overlying Ravenscrag Formation, the two are separated by the Cretaceous-Paleogene boundary and are now treated separately. The contact is abrupt but conformable, and occurs at the base of the No. 1 or Ferris coal seam of the Ravenscrag Formation.[3]

The Frenchman is separated from the underlying formations by an erosional unconformity, and depending on the depth of the erosion, the Frenchman rests on the Whitemud Formation, the Battle Formation, the Eastend Formation, or the Bearpaw Formation.[3] It is equivalent in age to the lower part of the Scollard Formation, the lower part of the Willow Creek Formation, the lower part of the Coalspur Formation in Alberta, and the Hell Creek Formation in Montana and North Dakota.

Paleontology

Mammals and birds

J.E. Storer described fossil mammals from the Gryde locality in the Frenchman Formation, including Parectypodus and Alphadon.[5] A bone (the humeral end of the left coracoid) of a bird attributed to the genus Cimolopteryx has also been described from the Gryde locality.[6]

Dinosaurs

Caenganathids closely related to Elmisaurus have been unearthed in the Frenchman Formation.[7]

Dinosaurs reported from the Frenchman Formation
Genus Species Location Stratigraphic position Material Notes Images
Ankylosaurus A. magniventris An ankylosaurine ankylosaurid File:Ankylosaurus magniventris reconstruction.png

Cimolopteryx

C. rara

Edmontosaurus

E. annectens

"Complete skull, [three or four] partial skulls."[8]

A hadrosaurid[9]

File:Anatotitan BW.jpg
E. saskatchewanensis

Junior synonym of E. annectens[9]

Thescelosaurus

T. assiniboiensis

Nearly complete skeleton File:Thescelosaurus filamented.jpg
Sphaerotholus[10] cf. S. buchholtzae "nearly complete left postorbital" The first pachycephalosaurid reported from the Frenchman Formation File:Sphaerotholus.jpg

Torosaurus

T. latus

Frill A large chasmosaurine ceratopsian distinct from Triceratops. Fossils have also been unearthed in the Scollard Formation.[11] File:Torosaurus BW.jpg

Chasmosaurinae indet.

[12]

Triceratops

T. prorsus

Redpath, Saskatchewan Nearly Complete Skull, one other partial skull [12] Being one of the most popular Dinosaurs, they are widely known. File:LA-Triceratops mount-2.jpg

Tyrannosaurus

T. rex

Nearly complete skeleton "Scotty", possibly the largest T. rex ever discovered, is from the Frenchman Formation File:Tyrannosaurus rex mmartyniuk.png

Plants

Two megafloral assemblages were collected from Grasslands National Park and the Chambery Coulee site. The differences in floral composition as well as evidence of forest fires indicated these two localities represented an ecological succession in a fire-disturbed environment, with burned mature forests being colonised by pioneer shrubs and then a subsequent reestablishment of coniferous and hardwood forest. Leaf analysis estimated mean annual temperatures of Script error: No such module "convert". in a largely deciduous mixed forest of temperate climate.[13][14] Template:Paleobiota-key-compact

Taxa Species Locality Material Notes Images
Acer-like Indeterminate GNP[13]
Alnus A. sp. GNP[13]
Araucarites A. sp. Chambery Coulee[13] Cone
Betula B. sp. GNP[13]
Cercidiphyllum C. sp. Chambery Coulee, GNP[13]
Cinnamomum-like Indeterminate Chambery Coulee, GNP[13] Likely not Cinnamomum.
Ficus? Indeterminate Chambery Coulee, GNP[13] Likely not in Moraceae.
Ginkgo G. sp. Chambery Coulee[13]
Juglans J. sp. Chambery Coulee[13] Seeds
Macginitiea M. sp. Chambery Coulee, GNP[13]
Magnolia M. sp. Chambery Coulee, GNP[13]
Marmarthia M. sp. Chambery Coulee[13] A Lauraceae, similar to Lindera.[15]
Menispermites M. sp. Chambery Coulee[13] Belongs to Menispermaceae.
Metasequoia M. sp. Chambery Coulee[13]
Parataxodium? Indeterminate Chambery Coulee[13] In need of revision.[16]
Platanus P. sp. Chambery Coulee, GNP[13]
Populus P. sp. Chambery Coulee, GNP[13]
Protophyllocladus P. sp. Chambery Coulee[13] Belongs to Podocarpaceae, similar to Phyllocladus.
Pseudoctenis P. sp. Chambery Coulee[13]
Quercus Q. sp. Chambery Coulee[13]
Rhus R. sp. Chambery Coulee, GNP[13]
Sabalites S. sp. Chambery Coulee[13]
Salix S. sp. Chambery Coulee, GNP[13]
Sapindus S. sp. GNP[13]
Sassafras S. sp. GNP[13]
Sequoia S. sp. Chambery Coulee[13]
Taxodium? T?. sp. Chambery Coulee[13]
Zelkova Z. sp. Chambery Coulee[13]

See also

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References

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  1. ↑ Furnival, G.M., 1942. Preliminary Map, Cypress Lake, Saskatchewan; Geological Survey of Canada, Paper 42-5, contains Preliminary Map 42-5, Cypress Lake, West of Third Meridian, Saskatchewan, Scale: 1 inch to 2 miles.
  2. ↑ Script error: No such module "citation/CS1".
  3. ↑ a b c d Glass, D.J., editor, 1997. Lexicon of Canadian Stratigraphy, vol. 4, Western Canada. Canadian Society of Petroleum Geologists, Calgary, Alberta, 1423 p. on CD-ROM, Template:ISBN.
  4. ↑ Lerbekmo, J.F., Sweet, A.R. and St. Louis, R.M. 1987. The relationship between the iridium anomaly and palynofloral events at three Cretaceous-Tertiary boundary localities in western Canada. Geological Society of America Bulletin, 99:25-330.
  5. ↑ Storer, J.E. (1991). The mammals of the Gryde local fauna, Frenchman Formation (Maastrichtian: Lancian), Saskatchewan. Journal of Vertebrate Paleontology, vol. 11, no. 3, p. 350-396.
  6. ↑ Tokaryk, T.T. and James, P.C. 1989. Cimolopteryx sp. (Aves: Charadriiformes) from the Frenchman Formation (Maastrichtian), Saskatchewan. Canadian Journal of Earth Sciences, vol. 26, p. 2729-2730.
  7. ↑ Script error: No such module "Citation/CS1".
  8. ↑ "Table 20.1," in Weishampel, et al. (2004). Page 440.
  9. ↑ a b Campione, N.E. and Evans, D.C. (2011). "Cranial Growth and Variation in Edmontosaurs (Dinosauria: Hadrosauridae): Implications for Latest Cretaceous Megaherbivore Diversity in North America." PLoS ONE, 6(9): e25186. Script error: No such module "CS1 identifiers".
  10. ↑ Script error: No such module "Citation/CS1".
  11. ↑ Script error: No such module "Citation/CS1".
  12. ↑ a b Tokaryk, T. 1986. Ceratopsian dinosaurs from the Frenchman Formation (Upper Cretaceous) of Saskatchewan. Canadian Field-Naturalist 100:192–196.
  13. ↑ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac Script error: No such module "Citation/CS1".
  14. ↑ Script error: No such module "Citation/CS1".
  15. ↑ Script error: No such module "Citation/CS1".
  16. ↑ Script error: No such module "Citation/CS1".

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