Glen Canyon Group

The Glen Canyon Group is a geologic group of formations that is spread across the U.S. states of Nevada, Utah, northern Arizona, north west New Mexico and western Colorado. It is sometimes called the Glen Canyon Sandstone in Colorado and Utah.[1] There are four formations within the group. From oldest to youngest, these are the Wingate Sandstone, Moenave Formation, Kayenta Formation, and Navajo Sandstone.[2] Part of the Colorado Plateau and the Basin and Range,[1] this group of formations was laid down during the Late Triassic and Early Jurassic, with the Triassic-Jurassic boundary within the Wingate Sandstone.[3][4] The top of the Glen Canyon Group is thought to date to the Toarcian stage of the Early Jurassic.[5]

Glen Canyon Group
Stratigraphic range: Late Triassic–Early Jurassic
TypeGroup
Sub-units(oldest to youngest) Wingate Sandstone, Moenave Formation, Kayenta Formation, Navajo Sandstone

Asterisks (*) below indicate usage by the U.S. Geological Survey.

Subunits
The Permian through Jurassic stratigraphy of the Colorado Plateau area of southeastern Utah that makes up much of the famous prominent rock formations in protected areas such as Capitol Reef National Park and Canyonlands National Park. From top to bottom: Rounded tan domes of the Navajo Sandstone, layered red Kayenta Formation, cliff-forming, vertically-jointed, red Wingate Sandstone, slope-forming, purplish Chinle Formation, layered, lighter-red Moenkopi Formation, and white, layered Cutler Formation sandstone. Picture from Glen Canyon National Recreation Area, Utah.

Group rank (alphabetical):[1]

History of investigation

There is no designated type locality for this group. It was named by Gregory and Moore in 1931 for exposures in walls that form the Glen Canyon of the Colorado River in Coconino County, Arizona and San Juan County, Utah. An overview of the group was given three years before by Gilluly and Reeside. Baker revised the work and named the Kayenta Formation in 1936. The work was revised again in 1955 by Averitt and others. They assigned the Shurtz Sandstone Tongue (new) and Lamb Point Tongue (new) to the Navajo Sandstone, and Cedar City Tongue (new) and Tenney Canyon Tongue (new) to the Kayenta Formation. In 1957 Harshbarger and others created an overview and revision that assigned the Moenave Formation and divided the Wingate Sandstone into the newly named Rock Point and Lukachukai members. The group's age was modified by Lewis and others in 1961 and the upper contact was revised by Phoenix in 1963. Poole and Stewart attempted to reduce the group's rank to a formation they called the Glen Canyon Sandstone in 1964 (change not recognized by the USGS). Areal extent limits were revised by Wilson and Stewart in 1967 and again by Green in 1974. Peterson and Pipiringos revised the upper contact and created an overview in 1979. In 1989 the age of the group was modified by Padian and separately by Dubiel (who also revised the lower contact). Condon modified the areal extent limits in 1992.[6]

Places found
Alcove in the Navajo Sandstone near Moab, Utah.

Geologic Province:[1]

Paleontology

Prehistoric animals from the various formations of the Glen Canyon Group include several types of dinosaurs, known from both skeletal remains and tracks. Dinosaur finds in the Wingate and Moenave formations are presently almost entirely tracks. The Kayenta Formation has a diverse skeletal fauna including the theropods "Syntarsus" kayentakatae and Dilophosaurus, the prosauropod Sarahsaurus, an unnamed heterodontosaurid, and the armored dinosaurs Scelidosaurus and Scutellosaurus. The Navajo Sandstone has body fossils of the theropod Segisaurus and an Ammosaurus-like prosauropod, and tracks.[5]

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See also

References

Notes
  1. GEOLEX database
  2. Harshbarger, J. W., C. A. Repenning, and J. H. Irwin. 1957. Stratigraphy of the uppermost Triassic and the Jurassic rocks of the Navajo country. U.S. Geological Survey, Reston, VA. Professional Paper 291.
  3. Lucas, S. G., A. B. Heckert, J. W. Estep, and O. J. Anderson. 1997. Stratigraphy, biostratigraphy, and sequence stratigraphy of the Upper Triassic Chinle Group, Four Corners region. pp. 81–107 in Anderson, O. J., B. Kues, and S. G. Lucas, editors. Mesozoic geology and paleontology of the Four Corners Region. New Mexico Geological Society, Socorro, NM. New Mexico Geological Society, 48th Field Conference.
  4. Lucas, S. G., A. B. Heckert, and L. H. Tanner. 2005. Arizona’s Jurassic fossil vertebrates and the age of the Glen Canyon Group. pp. 95–104 in Heckert, A. B. and S. G. Lucas (editors). Vertebrate paleontology in Arizona. New Mexico Museum of Natural History and Science, Albuquerque, NM. Bulletin 29.
  5. Weishampel, David B.; Barrett, Paul M.; Coria, Rodolfo A.; Le Loueff, Jean; Xu Xing Zhao Xijin; Sahni, Ashok; Gomani, Elizabeth M.P.; Noto, Christopher N. (2004). "Dinosaur distribution". In Weishampel, David B.; Dodson, Peter; Osmólska Halszka (eds.). The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 517–606. ISBN 0-520-24209-2.
  6. For the whole section, except where noted: GEOLEX database Bibliographic References

Works cited
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