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The Denver Formation is a geological formation that is present within the central part of the Denver Basin that underlies the Denver, Colorado, area. It ranges in age from Late Cretaceous (Maastrichtian) to early Paleocene, and includes sediments that were deposited before, during and after the Cretaceous-Paleogene boundary event.Tweto, O. 1979. Geologic map of Colorado. U.S. Geological Survey, Map G77115.
The formation is known for its paleontology resources, including dinosaur remains that are found in the Late Cretaceous part of the formation, and it includes aquifers that are important sources of water for the area. USGS Aquifer Basics[2]
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.
Several early Paleocene lava are present in the upper part of the Denver Formation at North and South Table Mountain near Golden, Colorado. The Ralston Dike, a body of intrusive monzonite located several miles to the northwest, probably represents the volcano from which the flows erupted.Van Horn, R. 1957. Bedrock geology of the Golden Quadrangle, Colorado. U.S. Geological Survey, Map GQ-103. Generally referred to as , they are classified either as monzonite (the lowest flow) and latite (the upper two flows), or as shoshonite. They contain the augite, plagioclase, and olivine altered to serpentine group, with accessory sanidine and/or orthoclase, apatite, magnetite, and biotite. One of the flows hosts a wide variety of zeolite minerals, including analcime, thomsonite, mesolite, chabazite, and others.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.
Plant 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. and remains of vertebrates, including 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. and ,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. are found throughout the Denver Formation.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. Dinosaur remains are restricted to the lower, Late Cretaceous, part.Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Cretaceous, North America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 574-588. .Carpenter, K. and Young, D.B. 2002. Late Cretaceous dinosaurs from the Denver Basin, Colorado. Rocky Mountain Geology, vol. 37, p. 237-254.
| Cionodon|style="background:#E6E6E6;" | C. arctatus|style="background:#E6E6E6;" | "Fragmentary maxilla, vertebrae, fragmentary postcranial elements.""Table 20.1," in Weishampel, et al. (2004). Page 442.|style="background:#E6E6E6;" | Later found to be indeterminate hadrosaurid remains."3.4 Colorado, United States; 6. Denver Formation," in Weishampel, et al. (2004). Page 581.| rowspan="99" | |
| Edmontosaurus | Indeterminate | |||
| Pachycephalosaurus | Indeterminate | |||
| Polyonax|style="background:#E6E6E6;" | P. mortuarius|style="background:#E6E6E6;" | "Horn fragments, vertebrae.""Table 23.1," in Weishampel, et al. (2004). Page 496. (type specimen)|style="background:#E6E6E6;" | A dubious ceratopsian | |
| Triceratops|style="background:#E6E6E6;" | T. galeus|style="background:#E6E6E6;" | "Nasal horn core."|style="background:#E6E6E6;" | A dubious ceratopsian | |
| Indeterminate | ||||
| Aublysodon|style="background:#E6E6E6;" | A. mirandus|style="background:#E6E6E6;" | Later found to be indeterminate tyrannosauroid remains.| rowspan="99" | ||
| Ornithomimus | O. velox | |||
| Tyrannosaurus | Indeterminate | |||
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