Denver Formation

Coordinates: 39°44′N 104°59′W / 39.74°N 104.98°W / 39.74; -104.98 (Denver Formation)
Source: Wikipedia, the free encyclopedia.
Denver Formation
Claystone, siltstone, sandstone
OtherConglomerate, tuff, coal, lava
Location
RegionColorado
CountryUnited States
Type section
Named forDenver, Colorado
Named byEmmons, Cross and Eldridge (1896)[2]

The Denver Formation is a geological

Cretaceous-Paleogene boundary event.[3][4]

The formation is known for its

aquifers that are important sources of water for the area.[6][7]

Stratigraphy

The Denver Formation rests on the Arapahoe Formation, and its base is marked by the first appearance of tuffaceous sediments. It is overlain by the Dawson Arkose.[4][8]

In 2002 the Denver Formation was included as part of a larger unconformity-bounded unit named the D1 sequence, in order to facilitate basin-wide studies and avoid confusion arising from the lateral and vertical facies changes that occur within the Denver Basin. The base of the D1 is marked by the abrupt facies change at the top of the Laramie Formation, and its top is placed at the base of a regional paleosol series. The Arapahoe Formation and the Dawson Arkose are also included in the D1 Sequence.[1]

Thickness and lithology

claystone, mudstone, siltstone, tuffaceous sandstone and, in some areas, andesitic conglomerate.[4][8] Beds of low-rank coal and carbonaceous shale occur in the upper 500 feet (150 m) in some areas.[10]

Several early Paleocene

Age and paleontology

The Denver Formation spans the

Epoch. The Cretaceous-Paleogene boundary occurs in the lower part of the formation, and an exposure of the boundary layer has been identified and documented on South Table Mountain near the city of Golden.[12]

vertebrates, including turtles[14] and mammals,[15] are found throughout the Denver Formation.[6] Dinosaur remains are restricted to the lower, Late Cretaceous, part.[5][8][16]

Cretaceous vertebrate paleofauna

Ornithischian dinosaurs

Ornithischians
reported from the Denver Formation
Genus Species Location Stratigraphic position Material Notes Images

Cionodon[17]

C. arctatus[17]

"Fragmentary maxilla, vertebrae, fragmentary postcranial elements."[18]

Later found to be indeterminate hadrosaurid remains.[17]

Edmontosaurus
Pachycephalosaurus
Triceratops

Edmontosaurus[17]

Indeterminate[17]

Pachycephalosaurus[17]

Indeterminate[17]

Polyonax[17]

P. mortuarius[17]

"Horn fragments, vertebrae."

type specimen
)

A dubious ceratopsian

Triceratops[17]

T. galeus[17]

"Nasal horn core."[19]

A dubious ceratopsian

Indeterminate[17]

Saurischian dinosaurs

Saurischians
of the Denver Formation
Genus Species Location Stratigraphic position Abundance Notes Images

Aublysodon[17]

A. mirandus[17]

Later found to be indeterminate tyrannosauroid remains.[17]

Ornithomimus
Tyrannosaurus

Ornithomimus[17]

O. velox[17]

Tyrannosaurus[17]

Indeterminate[17]

See also

References

  1. ^ a b c Raynolds, R.G. 2002. Upper Cretaceous and Tertiary stratigraphy of the Denver Basin, Colorado. Rocky Mountain Geology, vol. 37, no. 2, p. 111-134.
  2. ^ a b Emmons, S.F., Cross, W. and Eldridge, G.H. 1896. Geology of the Denver Basin in Colorado. U.S. Geological Survey, Monograph 27, p. 160.
  3. ^ U.S. Geological Survey. "Geologic Unit: Denver Formation". Retrieved 2014-12-27.
  4. ^ a b c Tweto, O. 1979. Geologic map of Colorado. U.S. Geological Survey, Map G77115.
  5. ^ .
  6. ^ a b Raynolds, R.G. and Johnson, K.R. 2003. Synopsis of the stratigraphy and paleontology of the uppermost Cretaceous and lower Tertiary strata in the Denver Basin, Colorado. Rocky Mountain Geology, vol. 38, no. 1, p. 171-181.
  7. ^ USGS Aquifer Basics[1]
  8. ^ a b c d e f Van Horn, R. 1957. Bedrock geology of the Golden Quadrangle, Colorado. U.S. Geological Survey, Map GQ-103.
  9. ^ U.S. Geological Survey Professional Paper 1698, Chapter F
  10. ^ "U.S. Geological Survey Professional Paper 1625-A, Chapter SD" (PDF). Archived from the original (PDF) on 2003-05-05. Retrieved 2014-08-30.
  11. ^ a b Kile D.E., 2004. Zeolites and associated minerals from the Table Mountains near Golden, Jefferson County, Colorado. Rocks and Minerals, vol. 79, no. 4, p. 218-238.
  12. ^ Kauffman, E.G., Upchurch, G.R. Jr., and Nichols, D.J., 2005. The Cretaceous-Tertiary boundary at South Table Mountain near Golden, Colorado. In: Extinction Events in Earth History, Lecture Notes in Earth Sciences, vol. 30, p. 365-392.
  13. ^ Johnson, K.R., Reynolds, M.L., Werth, K.W., and Thomasson, J.R. 2003. Overview of the Late Cretaceous, early Paleocene, and early Eocene megafloras of the Denver Basin, Colorado. Rocky Mountain Geology, vol. 38, no. 1, p. 101-120.
  14. ^ Hutchison, J.H. and Holroyd, P.A. 2003. Late Cretaceous and early Paleocene turtles of the Denver Basin, Colorado. Rocky Mountain Geology, vol. 38, no. 1, p. 121-142.
  15. ^ Eberle, J.J. 2003. Puercan mammalian systematics and biostratigraphy in the Denver Formation, Denver Basin, Colorado. Rocky Mountain Geology, vol. 38, no. 1. p. 143-169.
  16. ^ Carpenter, K. and Young, D.B. 2002. Late Cretaceous dinosaurs from the Denver Basin, Colorado. Rocky Mountain Geology, vol. 37, p. 237-254.
  17. ^ a b c d e f g h i j k l m n o p q r s "3.4 Colorado, United States; 6. Denver Formation," in Weishampel, et al. (2004). Page 581.
  18. ^ "Table 20.1," in Weishampel, et al. (2004). Page 442.
  19. ^ a b "Table 23.1," in Weishampel, et al. (2004). Page 496.

Bibliography

  • Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp. 

External links


39°44′N 104°59′W / 39.74°N 104.98°W / 39.74; -104.98 (Denver Formation)