The Moenave Formation is a

Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Creta ...

geologic

formation Formation may refer to: Linguistics * Back-formation, the process of creating a new lexeme by removing or affixes * Word formation, the creation of a new word by adding affixes Mathematics and science * Cave formation or speleothem, a secondary ...

, in the Glen Canyon Group. It is found in

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to its ...

and

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a U.S. state, state in the Southwestern United States. It is the list of U.S. states and territories by area, 6th largest and the list of U.S. states and territories by population, 14 ...

. The Moenave was deposited on an erosion surface on the

Chinle Formation The Chinle Formation is an Upper Triassic continental geological formation of fluvial, lacustrine, and palustrine to eolian deposits spread across the U.S. states of Nevada, Utah, northern Arizona, western New Mexico, and western Colorado. In ...

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 Mya. The J ...

uplift and

unconformity An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval o ...

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 Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% ...

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 minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especia ...

. 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 period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

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 Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period (Cenomanian stage) and are the closest living ...

indet. (similar to ''

Protosuchus ''Protosuchus'' is an extinct genus of carnivorous crocodylomorph from the Early Jurassic. The name ''Protosuchus'' means "first crocodile", and is among the earliest animals that resemble crocodilians. ''Protosuchus'' was about in length and ...

'') - "footprints" *'' Eubrontes'' - "footprints, resting tracks and swim tracks" * Eucynodontia indet. - "footprints" *'' Gigandipus'' - "footprints" *'' Grallator'' - "footprints, resting tracks (?) and

trace fossil A trace fossil, also known as an ichnofossil (; from el, ἴχνος ''ikhnos'' "trace, track"), is a fossil record of biological activity but not the preserved remains of the plant or animal itself. Trace fossils contrast with body fossils, ...

remains" *indeterminate

body fossils, such as unnamed specimens placed in the Coelacanthiformes,

Dipnoi Lungfish are freshwater vertebrates belonging to the order Dipnoi. Lungfish are best known for retaining ancestral characteristics within the Osteichthyes, including the ability to breathe air, and ancestral structures within Sarcopterygii, in ...

Palaeoniscidae Palaeoniscidae is an extinct family of ray-finned fishes (Actinopterygii) ascribed to the order Palaeonisciformes. The family includes the genus ''Palaeoniscum'' and potentially other Palaeozoic and Mesozoic early actinopterygian genera. The ...

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

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

*''

Protosuchus richardsoni ''Protosuchus'' is an extinct genus of carnivorous crocodylomorph from the Early Jurassic. The name ''Protosuchus'' means "first crocodile", and is among the earliest animals that resemble crocodilians. ''Protosuchus'' was about in length an ...

'' - protosuchid crocodyliform known from several partial to complete skeletons. * cf. '' Pteraichnus'' - "footprints" *''Pteraichnus'' - "footprints" * Pterosauria indet. - "footprints" * Sphenodontia indet. - "footprints" *

Theropoda Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally ca ...

indet. (similar to '' "Coelophysis" rhodesiensis'') - "

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characterist ...

from a juvenile and isolated

teeth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, te ...

" * Neotheropoda ident. - Single VertebraeAdam D. Marsh, Andrew R. C. Milner, Jerald D. Harris, Donald D. De Blieux & James I. Kirkland (2021
A non-averostran neotheropod vertebra (Dinosauria: Theropoda) from the earliest Jurassic Whitmore Point Member (Moenave Formation) in southwestern Utah
Journal of Vertebrate Paleontology, DOI: 10.1080/02724634.2021.1897604

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 JurassicWeishampel, David B; et al. (2004). "Dinosaur distribution (Early Jurassic, North America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, 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. Pages 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, 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

Paleofauna

Glen Canyon Group

See also

References