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Denver Formation
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 latest 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 paleontological 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 )()〕
==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.〔〔
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.〔
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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