Kayenta Formation

Kayenta Formation

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The '''Kayenta Formation''' is a geologic [[formation (geology)|layer]] in the [[Glen Canyon Group]] that is spread across the [[Colorado Plateau]] province of the [[United States]], including northern [[Arizona]], northwest [[Colorado]], [[Nevada]], and [[Utah]]. This rock formation is particularly prominent in southeastern Utah, where it is seen in the main attractions of a number of national parks and monuments. These include [[Zion National Park]], [[Capitol Reef National Park]], the [[San Rafael Swell]], and [[Canyonlands National Park]]. The Kayenta Formation frequently appears as a thinner dark broken layer below [[Navajo Sandstone]] and above [[Wingate Sandstone]] (all three formations are in the same group). Together, these three formations can result in immense vertical cliffs of {{convert|2000|ft|m}} or more. Kayenta layers are typically red to brown in color, forming broken ledges. ===Southwest Utah=== The red and mauve Kayenta [[siltstone]]s and [[sandstone]]s that form the slopes at base of the [[Navajo Sandstone]] cliffs record the record of low to moderate energy streams. Poole (1997) has shown that the streams still flowed toward the east depositing from 150 to 210 m (500 to about 700 feet) of [[sediment]] here. The [[sedimentary rocks|sedimentary structures]] showing the channel and [[flood plain]] deposits of [[streams]] are well exposed on switchbacks below the tunnel in Pine Creek Canyon. In the southeastern part of Zion National Park a stratum of [[cross bedding|cross bedded]] [[sandstone]] is found roughly halfway between the top and bottom of the Kayenta Formation. It is a "tongue" of sandstone that merges with the Navajo formation east of [[Kanab]], and it shows that [[desert]] conditions occurred briefly in this area during Kayenta time. This tongue is the ledge that shades the lower portion of the Emerald Pool Trail, and it is properly called Navajo, not Kayenta. [[Fossil]] [[mudcrack]]s attest to occasional seasonal [[climate]], and thin [[limestones]] and [[fossil trackway|fossilized trail]]s of [[aquatic animal|aquatic]] [[snails]] or [[worm]]s mark the existence of [[ponds]] and [[lakes]]. The most interesting fossils, however, are the [[dinosaur]] tracks that are relatively common in Kayenta mudstone. These vary in size, but all seem to be the tracks of three-toed [[reptiles]] that walked upright, leaving their tracks in the muds on the flood plains. Unfortunately, so far no bone materials have been found in the County that would enable more specific identification. Apparently during Kayenta time Zion was situated in a climatic belt like that of [[Senegal]] with rainy summers and dry winters at the southern edge of a great desert. The influence of the [[desert]] was about to predominate, however, as [[North America]] drifted northward into the arid desert belt. ===Southeast Utah=== [[Image:PartingLineation.JPG|thumb|275px|[[Parting lineation]], from lower right to upper left; Kayenta Formation, [[Canyonlands National Park]].]] [[Image:SEUtahStrat.JPG|thumb|300px|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.]] In most sections that include all three [[geologic formation]]s of the [[Glen Canyon]] group the Kayenta is easily recognized. Even at a distance it appears as a dark-red, maroon, or lavender band of thin-bedded material between two thick, massive, cross bedded [[stratum|strata]] of buff, tan, or light-red color. Its position is also generally marked by a topographic break. Its weak beds form a bench or platform developed by stripping the Navajo sandstone back from the face of the Wingate cliffs. The Kayenta is made up of beds of sandstone, [[shale]], and limestone, all [[wikt:lenticular|lenticular]], uneven at their tops, and discontinuous within short distances. They suggest deposits made by shifting [[stream]]s of fluctuating volume. The sandstone beds, from less than {{convert|1|in|mm|sing=on}} to more than {{convert|10|ft|m}} thick, are composed of relatively coarse, well-rounded [[quartz]] grains cemented by [[lime (mineral)|lime]] and [[iron]]. The thicker beds are indefinitely cross bedded. The shales are essentially [[fine-grained]], very thin sandstones that include lime [[concretions]] and balls of consolidated [[mud]]. The limestone appears as solid gray-blue beds, a few inches to a few feet thick, and as lenses of limestone [[Conglomerate (geology)|conglomerate]]. Most of the limestone lenses are less than {{convert|25|ft|m}} long, but two were traced for nearly {{convert|500|ft|m}} and one for {{convert|1650|ft|m}}. Viewed as a whole the Kayenta, is readily distinguished from the geologic formations above and below it. It is unlike them in composition, color, manner of bedding, and sedimentary history. Obviously the conditions of sedimentation changed in passing from the Wingate Sandstone formation to the Kayenta and from the Kayenta to the Navajo sandstone, but the nature and regional significance of the changes have not been determined. In some measured sections the transition from Wingate to Kayenta is gradual; the material in the basal Kayenta, beds seems to have been derived from the Wingate immediately below and redeposited with only the discordance characteristic of fluviatile sediments. But in many sections the contact between the two formations is unconformable; the basal Kayenta consists of conglomerate and lenticular sandstone that fills depressions eroded in the underlying beds. In [[Moqui Canyon]] near Red Cone Spring nearly {{convert|10|ft|m}} of Kayenta limestone conglomerate rests in a long meandering [[valley]] cut in Wingate. Likewise, the contact between the Kayenta and the Navajo in places seems to be gradational, but generally a thin jumbled mass of sandstone and shales, chunks of shale and limestone, mud balls, and concretions of lime and iron, lies at the base of the fine-grained, cross bedded Navajo. Mud cracks, a few [[ripple marks]], and incipient drainage channels were observed in the topmost bed of the Kayenta on [[Red Rock Plateau]]; and in west Glen Canyon, wide sand-filled cracks appear at the horizon. These features indicate that, in places at least, the Wingate and Kayenta were exposed to [[erosion]] before their overlying geologic formations were deposited, are it may be that the range in thickness of the Kayenta thus in part (is) accounted for. ==Glen Canyon== The Kayenta Formation is approximately {{convert|400|ft|m}} thick and consists of a fine-grained sandstone interbedded with layers of siltstone. The alternation of these units generally produces a series of ledges and slopes between the cliffs of the Navajo and [http://3dparks.wr.usgs.gov/coloradoplateau/lexicon/moenave.htm Moenave formation]. Dinosaur tracks are fairly common in the siltstone, and [[fresh water]] [[mussels]] and [[snail]]s occur but are rare. The Kayenta Formation is colored pale red and adds to the splendor of the [[Vermilion Cliffs]]. It accumulated as deposits of rivers. ===Amphibians=== {| class="wikitable" align="center" width="100%" |- ! colspan="7" align="center" |'''[[Amphibian]]s reported from the Kayenta Formation''' |- ! Genus ! Species ! Location ! Stratigraphic position ! Material ! Notes ! Images |- | ''[[Prosalirus]]'' | | * Arizona. | | | | rowspan="99" align="center"| [[File:Prosalirus BW.jpg|thumb|center|150px|''[[Prosalirus]]'']] |- |} ===Anapsids=== {| class="wikitable" align="center" width="100%" |- ! colspan="7" align="center" |'''[[Anapsids]] reported from the Kayenta Formation''' |- ! Genus ! Species ! Location ! Stratigraphic position ! Material ! Notes ! Images |- | ''[[Kayentachelys]]'' | | * Arizona | | | | rowspan="99" align="center"| |- |} ===Crurotarsans=== {| class="wikitable" align="center" width="100%" |- ! colspan="7" align="center" |'''[[Crurotarsans]] reported from the Kayenta Formation''' |- ! Genus ! Species ! Location ! Stratigraphic position ! Material ! Notes ! Images |- | ''[[Kayentasuchus]]'' | Geographically present in Arizona. | | | | rowspan="99" align="center"| |- |} ===Ornithodires=== Indeterminate ornithischian remains located in Arizona, USA. Ornithischian tracks located in Arizona, USA. An unnamed [[Heterodontosaurid]] genus located in Arizona, USA. Indeterminate theropod remains located in Arizona, USA. Theropod tracks located in Arizona and Utah, USA. Possible theropod tracks located in Arizona, Colorado, and Utah, USA. Unnamed coelophysoid genus located in Arizona, USA. {| class="wikitable" align="center" width="100%" |- ! colspan="7" align="center" |'''[[Ornithodires]] reported from the Kayenta Formation''' |- ! Genus ! Species ! Location ! Stratigraphic position ! Material ! Notes ! Images |- | ''[[Dilophosaurus]]'' | ''D. wetherilli'' | * Arizona | | "2 associated subadult skeletons, partial skeleton, 4 other fragmentary individuals." | | rowspan="99" | [[Image:Dilophosaurus.jpg|thumb|center|150px|''[[Dilophosaurus]]'']] [[Image:Scutellosaurus.jpg|thumb|center|150px|''[[Scutellosaurus]]'']] |- | ''[[Kayentavenator]]'' | ''K. elysiae'' | * Arizona | | | Originally referred to ''M. kayentakatae'' by Rowe. |- | ''[[Massospondylus]]'' | ''Massospondylus'' sp. | * Arizona | | | Now known as [[Sarahsaurus]] |- | ''[[Megapnosaurus]]'' | ''M. kayentakatae'' | * Arizona | | "1 articulated skull and postcranial skeleton, 2 fragmentary skeletons, 1 incomplete skeleton" Both adults and sub adults are known from the formation. | Note: Referred to as ''Syntarsus'' by Weishampel et al. |- | ''[[Rhamphinion]]'' | ''R. jenkinsi'' | * Little Colorado River Valley, Arizona. | * Middle | | |- | ''[[Scelidosaurus]]'' | ''Scelidosaurus'' sp. | * Arizona | | | |- | ''[[Scutellosaurus]]'' | ''S. lawleri'' | * Arizona | | "Fragmentary skull and skeleton from at least [two] individuals." | |- |} ===Synapsids=== {| class="wikitable" align="center" width="100%" |- ! colspan="7" align="center" |'''[[Tritylodonts]] of the Kayenta Formation''' |- ! Genus ! Species ! Location ! Stratigraphic position ! Material ! Notes ! Images |- | ''[[Dinnebitodon]]'' | ''D. amarali'' | Geographically located in Arizona, USA. | | | | rowspan="99" | [[Image:kayentatheriumskull.jpg|thumb|center|175px|Skull of ''[[Kayentatherium]]'']] |- | ''[[Kayentatherium]]'' | ''K. wellesi'' | Geographically located in Arizona, USA. | | | |- | ''[[Oligokyphus]]'' | | Geographically located in Arizona, USA. | | |- |} ==See also== * [[List of fossil sites]] ''(with link directory)'' * [[Kayenta, Arizona]] * [[List of dinosaur-bearing rock formations]] ==External links== * [http://3dparks.wr.usgs.gov/coloradoplateau/lexicon/ U.S.G.S Lexicon of Colorado Plateau Stratigraphy] {{coord missing|Arizona}}