The Moenave Formation is a

Mesozoic The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...

geologic formation, in the Glen Canyon Group. It is found in

Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...

and

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

. The Moenave was deposited on an erosion surface on the Chinle Formation following an early

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

uplift and unconformity that represents about ten million years of missing sedimentation.Biek, Robert F.; Grant C. Willis, Micheal D. Hylland, and Hellmut H. Doelling (August 2003). "Geology of Zion National Park, Utah". In Paul B. Anderson (editor). Geology of Utah's Parks and Monuments. Bryce Canyon Natural History Association and Utah Geological Association. Periodic incursions of shallow seas from the north during the Jurassic flooded parts of Wyoming, Montana, and a northeast–southwest trending trough on the Utah/Idaho border. The Moenave was deposited in a variety of river, lake, and flood-plain environments, near the ancient Lake Dixie. The oldest beds of this formation belong to the Dinosaur Canyon Member, a reddish, slope-forming rock layer with thin beds of siltstone that are interbedded with mudstone and fine sandstone. The Dinosaur Canyon, with a local thickness of , was probably laid down in slow-moving streams, ponds and large lakes. Evidence for this is in cross-bedding of the sediments and large numbers of fish fossils. The upper member of the Moenave is the pale reddish-brown with a thickness of and cliff-forming Springdale Sandstone. It was deposited in swifter, larger, and more voluminous streams than the older Dinosaur Canyon Member. Fossils of large sturgeon-like freshwater

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

have been found in the beds of the Springdale Sandstone. The next member in the Moenave Formation is the thin-bedded Whitmore Point, which is made of mudstone and

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...

. The lower red cliffs visible from the Zion Human History Museum (until 2000 the Zion Canyon Visitor Center) and the St. George Dinosaur Discovery Site, discovered on February 26, 2000, are accessible examples of this formation.

Paleofauna

Dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

remains are among the fossils that have been recovered from the formation, with only one species-level taxon, ''Protosuchus richardsoni'', based on body fossils. *'' Anomoepus'' – "footprints" *'' Batrachopus'' – "footprints" *'' Characichnos'' – "swim tracks" * Crocodylia indet. (similar to '' Protosuchus'') – "footprints" *'' Eubrontes'' – "footprints, resting tracks and swim tracks" * Eucynodontia indet. – "footprints" *'' Gigandipus'' – "footprints" *'' Grallator'' – "footprints, resting tracks (?) and

trace fossil A trace fossil, also called an ichnofossil (; ), is a fossil record of biological activity by lifeforms, but not the preserved remains of the organism itself. Trace fossils contrast with body fossils, which are the fossilized remains of part ...

remains" *indeterminate

body fossils, such as unnamed specimens placed in the

Coelacanthiformes Coelacanths ( ) are an ancient group of Sarcopterygii, lobe-finned fish (Sarcopterygii) in the Class (biology), class Actinistia. As sarcopterygians, they are more closely related to lungfish and tetrapods (the terrestrial vertebrates including ...

, Dipnoi, Palaeoniscidae and the Semionotidae, and trace fossils not referable to any known

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

*'' Protosuchus richardsoni'' – protosuchid crocodyliform known from several partial to complete skeletons. *

cf. The abbreviation cf. (short for either Latin or , both meaning 'compare') is generally used in writing to refer the reader to other material to make a comparison with the topic being discussed. However some sources offer differing or even contr ...

'' Pteraichnus'' – "footprints" *''Pteraichnus'' – "footprints" * Pterosauria indet. – "footprints" * Sphenodontia indet. – "footprints" * Theropoda indet. (similar to '' "Coelophysis" rhodesiensis'') – "

vertebra Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spina ...

from a juvenile and isolated teeth" * Neotheropoda ident. – Single Vertebrae

Glen Canyon Group

The 4 members of the Glen Canyon Group, from youngest (top member) to oldest (bottom member), are: # Navajo Sandstone – early JurassicAnonymous (2011b
''Navajo Sandstone''

. U.S. Geological Survey, Reston, Virginia. last accessed August 18, 2013 # Kayenta Formation – early Jurassic Weishampel, David B; et al. (2004). "Dinosaur distribution (Early Jurassic, North America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): ''The Dinosauria'', 2nd edition., Berkeley: University of California Press. pp. 530–532. . # Moenave Formation – early Jurassic # Wingate Sandstone – early JurassicLucas, 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.

References

* Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): ''The Dinosauria'', 2nd ed., Berkeley: University of California Press. 861 pp. . {{Chronostratigraphy of Nevada Geologic formations of Arizona Jurassic Arizona Jurassic geology of Utah Early Jurassic North America Hettangian Stage Ichnofossiliferous formations Siltstone formations of the United States Sandstone formations of the United States

Paleofauna

Glen Canyon Group

See also

References