Nugget Sandstone near Red Fleet Reservoir, Uintah County, Utah. Uniform grain size and these large cross-stratification are indicative of an ancient sand dune.
Nugget Sandstone showing a bounding surface between two sets of ancient sand dunes, where wind scour eroded the top of the lower dune before the second dune advanced over it. Red Fleet Reservoir, Uintah County, Utah.
Eubrontes track in the Nugget Sandstone, Red Fleet State Park, Uintah County, Utah.

The Nugget Sandstone is a Late Triassic to Early Jurassic geologic formation that outcrops in Colorado, Idaho, Wyoming, and Utah, western United States.

In Wyoming, it is composed of a lower hematite-stained siltstone and thin-bedded sandstone. The upper part is a salmon-pink and light-gray, fine- to medium-grained cliff-forming sandstone that exhibits massive bedding to large scale cross-beds of dunes. Thickness ranges up to 86.9 m (285 feet).[1]

Fossil theropod tracks have been reported from the formation.[2]

Fossil content

Intermediate theropod, sphenosuchian, drepanosaurid and sphenodontian remains are known.[3]

Paleofauna reported from the Nugget Sandstone
Genus Species Material Notes Images
Caelestiventus[4] C. hanseni Most of the skull, a complete lower jaw, a finger bone A dimorphodontid pterosaur, the first known diagnostic pterosaur in North America.
Other fossils

Ichnofossils

See also

References

  1. ^ Johnson, J.F. and Sutherland, W.M., 2009, Geologic map of the Lander 30' x 60' quadrangle, Fremont County, Wyoming, Wyoming State Geological Survey, Map Series MS-87, 1:100,000.
  2. ^ Weishampel, et al. (2004). "Dinosaur distribution." Pp. 517-607.
  3. ^ B. B. Britt, D. J. Chure, G. F. Engelmann and J. D. Shumway. 2016. Rise of the erg—paleontology and paleoenvironments of the Triassic-Jurassic transition in northeastern Utah. Geology of the Intermountain West 3:1-32
  4. ^ Brooks B. Britt; Fabio M. Dalla Vecchia; Daniel J. Chure; George F. Engelmann; Michael F. Whiting; Rodney D. Scheetz (2018). "Caelestiventus hanseni gen. et sp. nov. extends the desert-dwelling pterosaur record back 65 million years". Nature Ecology & Evolution. 2 (9): 1386–1392. Bibcode:2018NatEE...2.1386B. doi:10.1038/s41559-018-0627-y. PMID 30104753. S2CID 51984440.

Bibliography

  • Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp. ISBN 0-520-24209-2

Further reading

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