{{Otheruses}}{{pp-semi-protected|small=yes}}{{Otheruses}}{{pp-semi-protected|small=yes}}
The
Kayenta Formation is a geologic layer in the
Glen Canyon GroupThe 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...
that is spread across the
Colorado PlateauThe Colorado Plateau, also called the Colorado Plateau Province, is a physiographic region of the Intermontane Plateaus, roughly centered on the Four Corners region of the southwestern United States. The province covers an area of 337,000 km² within western Colorado, northwestern New Mexico,...
province of the
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
, including northern
ArizonaThe State of Arizona is a state located in the southwestern region of the United States. The capital and largest city is Phoenix. The second largest city is Tucson, followed in size by the four Phoenix metropolitan area cities of Mesa, Glendale, Chandler, and Scottsdale.Arizona was the 48th and...
, northwest
ColoradoColorado is a U.S. state located in the Rocky Mountain region of the United States of America. It may also be considered to be part of the Western and Southwestern regions of the United States. Colorado entered statehood in 1876 and was nicknamed the “Centennial State”...
,
NevadaNevada is a state located in the western region of the United States. The capital is Carson City and the largest city is Las Vegas. The state's nickname is Silver State, due to the large number of silver deposits that were discovered and mined there...
, and
UtahUtah is a western state of the United States. It was the 45th state admitted to the Union, on January 4, 1896. Approximately 80 percent of Utah's 2,736,424 people live along the Wasatch Front, centering around Salt Lake City. In contrast, vast expanses of the state are nearly uninhabited, making...
. 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 ParkZion National Park is a national park located in the Southwestern United States, near Springdale, Utah. A prominent feature of the 229-square-mile park is Zion Canyon, 15 miles long and up to half a mile deep, cut through the reddish and tan-colored Navajo Sandstone by the North Fork of...
,
Capitol Reef National ParkCapitol Reef National Park is a United States National Park, in south-central Utah. It is 100 miles long but fairly narrow. The park, established in 1971, preserves 378 mi² and is open all year, although May through September are the most popular months.Called "Wayne Wonderland" in the 1920s by...
, the
San Rafael SwellThe San Rafael Swell is a large geologic feature located in south-central Utah, USA about 30 miles west of Green River, Utah. The San Rafael Swell, approximately by , consists of a giant dome-shaped anticline of sandstone, shale, and limestone that was pushed up millions of years ago...
, and
Canyonlands National ParkCanyonlands National Park is located in the American state of Utah, near the city of Moab and preserves a colorful landscape eroded into countless canyons, mesas and buttes by the Colorado River, the Green River, and their respective tributaries. The rivers divide the park into four districts: the...
. The Kayenta Formation frequently appears as a thinner dark broken layer below
Navajo SandstoneNavajo Sandstone is a geologic formation in the Glen Canyon Group that is spread across the U.S. states of northern Arizona, northwest Colorado, Nevada, and Utah . It is located in the Colorado Plateau province of the United States...
and above
Wingate SandstoneWingate Sandstone is an Early Jurassic geologic formation 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...
(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 siltstones and sandstones that form the slopes at base of the
Navajo SandstoneNavajo Sandstone is a geologic formation in the Glen Canyon Group that is spread across the U.S. states of northern Arizona, northwest Colorado, Nevada, and Utah . It is located in the Colorado Plateau province of the United States...
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
sedimentSediment is any particulate matter that can be transported by fluid flow, and which eventually is deposited.Sediments are most often transported by water transported by wind and glaciers...
here. The sedimentary structures showing the channel and flood plain deposits of
streamsIn computer networking, STREAMS is the native framework in Unix System V for implementing character devices.STREAMS was designed as a modular architecture for implementing full-duplex I/O between kernel or user space processes and device drivers. Its most frequent uses have been in developing...
are well exposed on switchbacks below the tunnel in Pine Creek Canyon.
In the southeastern part of Zion National Park a stratum of cross bedded
sandstoneSandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any color, but the most common colors are tan, brown, yellow,...
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
desertA desert is a landscape or region that receives almost no precipitation. Deserts are defined as areas with an average annual precipitation of less than per year, or as areas where more water is lost by evapotranspiration than falls as precipitation. In the Köppen climate classification system,...
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.
FossilFossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous rock formations and sedimentary layers is known as the fossil record...
mudcrackMudcracks are sedimentary structures which form when fine grained sediment dries out or desiccates. They are generally polygonal in plan view, and V-shaped in cross section. They may be preserved in lithified rock....
s attest to occasional seasonal
climateClimate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and numerous other meteorological elements in a given region over long periods of time...
, and thin limestones and fossilized trails of
aquaticAn aquatic animal is an animal, either vertebrate or invertebrate, which lives in water for most or all of its life. It may breathe air or extract its oxygen from that dissolved in water through specialised organs called gills, or directly through its skin. Natural environments and the animals that...
snails or
wormThe term worm is used to describe many different distantly-related animals which have a long cylindrical body and no legs.Most animals called "worms" are invertebrates, but the term is also used for the amphibian caecilians and the slow worm Anguis, a legless burrowing lizard...
s mark the existence of ponds and lakes. The most interesting fossils, however, are the
dinosaur{{Otheruses}}{{pp-semi-protected|small=yes}}{{Otheruses}}{{pp-semi-protected|small=yes}}{{Taxobox|name = Dinosaurs|fossil_range = {{Fossil range|230|65|earliest=230|latest=0|PS=
Descendant taxon Aves survives to present.}}|image = field_dinos_2.jpg...
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
SenegalSenegal , officially the Republic of Senegal, is a country south of the Sénégal River in western Africa. Senegal is bounded by the Atlantic Ocean to the west, Mauritania to the north, Mali to the east, and Guinea and Guinea-Bissau to the south, and it also encircles The Gambia on its three sides,...
with rainy summers and dry winters at the southern edge of a great desert. The influence of the
desertA desert is a landscape or region that receives almost no precipitation. Deserts are defined as areas with an average annual precipitation of less than per year, or as areas where more water is lost by evapotranspiration than falls as precipitation. In the Köppen climate classification system,...
was about to predominate, however, as
North AmericaNorth America is the northern continent of the Americas, situated in the Earth's northern hemisphere and in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific...
drifted northward into the arid desert belt.
Southeast Utah
In most sections that include all three
geologic formationA formation or geological formation is the fundamental unit of lithostratigraphy. A formation consists of a certain number of rock strata that have a comparable lithology, facies or other similar properties...
s of the
Glen CanyonGlen Canyon is a canyon that is located in southeastern and south central Utah and northwestern Arizona within the Vermilion Cliffs area. It was carved by the Colorado River....
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
strataIn geology and related fields, a stratum is a layer of rock or soil with internally consistent characteristics that distinguishes it from contiguous layers. Each layer is generally one of a number of parallel layers that lie one upon another, laid down by natural forces. They may extend over...
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,
shaleShale is a fine-grained, clastic sedimentary rock composed of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable...
, and limestone, all lenticular, uneven at their tops, and discontinuous within short distances. They suggest deposits made by shifting
streamA stream is a flowing body of water with a current, confined within a bed and stream banks. Depending on its locale or certain characteristics, a stream may be referred to as a branch, brook, beck, burn, creek, kill, lick, rill, river syke, bayou, rivulet, or run...
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
quartzQuartz is the second most abundant mineral in the Earth's continental crust . It is made up of a continuous framework of SiO
4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO
2.There are many different varieties of...
grains cemented by
limeLime is a general term for calcium-containing inorganic materials, in which carbonates, oxides and hydroxides predominate. Strictly speaking, lime is calcium oxide or calcium hydroxide. It is also the name for a single mineral of the CaO composition, occurring very rarely...
and
ironIron is a metallic chemical element with the symbol Fe and atomic number 26. Iron is a group 8 and period 4 element and is therefore classified as a transition metal. Iron and iron alloys are by far the most common metals and the most common ferromagnetic materials in everyday use...
. The thicker beds are indefinitely cross bedded. The shales are essentially fine-grained, very thin sandstones that include lime concretions and balls of consolidated
mudMud is a liquid or semi-liquid mixture of water and some combination of soil, silt, and clay. Ancient mud deposits harden over geological time to form sedimentary rock such as siltstone or solid, mudrock lutites. When geological deposits of mud are formed in estuaries the resultant layers are...
. The limestone appears as solid gray-blue beds, a few inches to a few feet thick, and as lenses of limestone
conglomerateA conglomerate is a rock consisting of individual clasts within a finer-grained matrix that have become cemented together. Conglomerates are sedimentary rocks consisting of rounded fragments and are thus differentiated from breccias, which consist of angular clasts...
. 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
valleyIn geology, a valley or dale is a depression with predominant extent in one direction. A very deep river valley may be called a canyon or gorge.The terms U-shaped and V-shaped are descriptive terms of geography to characterize the form of valleys...
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 marksIn geology, ripple marks are sedimentary structures that were deposited in a flow. that indicate agitation by water or wind. Ripple marks formed by water consist of two basic types:...
, 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
erosionErosion is a gravity driven process that moves solids in the natural environment or their source and deposits them elsewhere...
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.
Grand 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
Moenave formations. Dinosaur tracks are fairly common in the siltstone, and
fresh waterFresh Water is the debut album by Australian rock and blues singer Alison McCallum, released in 1972. Rare for an Australian artist at the time, it came in a gatefold sleeve...
mussels and
snailThe word snail is a common name for almost all members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word snail is used in a general sense, it includes sea snails, land snails and freshwater snails. Snails lacking a shell or having only a very small one are...
s occur but are rare. The Kayenta Formation is colored pale red and adds to the splendor of the
Vermilion CliffsThe Vermilion Cliffs are the second "step" up in the five-step Grand Staircase of the Colorado Plateau. Reddish or vermilion-colored cliffs are found along U.S. Highway 89 and U.S. Highway 89A near Kanab, Utah . They extend from a location near Page, Arizona, west for a considerable distance, in...
. It accumulated as deposits of rivers.
Amphibians
AmphibianAmphibians , such as frogs, toads, salamanders, newts, and caecilians, are ectothermic animals that metamorphose from a juvenile water-breathing form, to an adult air-breathing form. Though amphibians typically have four limbs, the Caecilians are notable for being limbless. Unlike other land...
s of the Kayenta Formation |
| Taxa |
Presence |
Notes |
Images |
Genus:
- Prosalirus
Prosalirus bitis is the name given to a fossil proto-frog found in Arizona in 1995, which has primitive features, but has mostly lost the salamander-like traits of its ancestors. It has a skeleton designed to absorb the force of jumping with its hind legs and tail. It is thought to have lived 190...
|
Geographically present in Arizona. |
|
|
Ornithischians
Dinosaur{{Otheruses}}{{pp-semi-protected|small=yes}}{{Otheruses}}{{pp-semi-protected|small=yes}}{{Taxobox|name = Dinosaurs|fossil_range = {{Fossil range|230|65|earliest=230|latest=0|PS= Descendant taxon Aves survives to present.}}|image = field_dinos_2.jpg...
s of the Kayenta Formation |
| Taxa |
Presence |
Notes |
Images |
Family:
- Heterodontosauridae
Heterodontosauridae is a family of early ornithischian dinosaurs that were likely among the most basal members of the group...
- Unnamed genus.
|
Geographically located in Arizona, USA. |
|
|
Genus:
- Scelidosaurus
Scelidosaurus is a genus of quadrupedal, lightly plated, herbivorous dinosaur about long. It lived during the Early Jurassic Period, during the Hettangian to Sinemurian stages around 208 to 194 million years ago...
- Scelidosaurus sp.
|
Geographically located in Arizona, USA. |
|
Genus:
- Scutellosaurus
Scutellosaurus is a genus of herbivorous dinosaur that lived in North America around 200 to 196 million years ago, in the Early Jurassic times....
- S. lawleri
|
Geographically located in Arizona, USA. |
|
Order:
- Ornithischia
Ornithischia or Predentata is an extinct order of beaked, herbivorous dinosaurs. The name ornithischia is derived from the Greek ornitheos meaning 'of a bird' and ischion meaning 'hip joint'...
- Indeterminate remains.
- Tracks.
|
Geographically located in Arizona, USA.
Geographically located in Arizona, USA. |
|
Saurischians
| Sauropodomorphs of the Kayenta Formation |
| Taxa |
Presence |
Notes |
Images |
Genus:
- Massospondylus
Massospondylus Massospondylus Massospondylus and (spondylos, "vertebra") is a genus of prosauropod dinosaur from the early Jurassic Period (Hettangian to Pliensbachian ages, ca. 200–183 million years ago). It was described by Sir Richard Owen in 1854 from...
- Massospondylus sp.
|
Geographically located in Arizona, USA. |
|
|
Dinosaur{{Otheruses}}{{pp-semi-protected|small=yes}}{{Otheruses}}{{pp-semi-protected|small=yes}}{{Taxobox|name = Dinosaurs|fossil_range = {{Fossil range|230|65|earliest=230|latest=0|PS= Descendant taxon Aves survives to present.}}|image = field_dinos_2.jpg...
s of the Kayenta Formation |
| Taxa |
Presence |
Notes |
Images |
Superfamily:
- Coelophysoidea
Coelophysoids were common dinosaurs of the Late Triassic and Early Jurassic periods. They were widespread geographically, probably living on all continents. Coelophysoids were all slender, carnivorous forms with a superficial similarity to the coelurosaurs, with which they were formerly...
- Unnamed genus.
|
Geographically located in Arizona, USA. |
|
|
Genus:
- Dilophosaurus
Dilophosaurus was a theropod dinosaur from the Pliensbachian stage of the Early Jurassic Period. The name means 'two-crested lizard', from the two crests of the animal...
- D. wetherilli
|
Geographically located in Arizona, USA. |
|
Genus:
- Megapnosaurus
Megapnosaurus was a dinosaur of the theropod family Coelophysidae, formerly called Syntarsus , living during the Early Jurassic. It was renamed by American entomologist Dr. Michael Ivie , Polish Australian Dr...
- M. kayentakatae
|
Geographically located in Arizona, USA. |
Note: Referred to as Syntarsus by Weishampel et al. |
Suborder:
- Theropoda
Theropods are a group of bipedal saurischian dinosaurs. Although they were primarily carnivorous, a number of theropod families evolved herbivory during the Cretaceous Period...
- Indeterminate remains.
- Tracks.
- Possible tracks.
|
Geographically located in Arizona, USA.
Geographically located in Arizona, USA.
Geographically located in Colorado, USA. |
|
Pterosaurs
PterosaurPterosaurs were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period...
s of the Kayenta Formation |
| Taxa |
Presence |
Notes |
Images |
Genus:
- Rhamphinion
Rhamphinion Rhamphinion Rhamphinion (meaning "beak nape"; Greek rhamphos, "beak" is a common part of "rhamphorhynchoid" names, and the remains of this animal came from the rear of the skull, i.e...
- R. jenkinsi
|
Geographically present in the Little Colorado River Valley, Arizona. Stratigraphically present in the middle part of the formation. |
|
|
See also
- List of fossil sites (with link directory)
- Kayenta, Arizona
Kayenta is a census-designated place which is part of the Navajo Nation and is in Navajo County, Arizona, United States. The population was 4,922 at the 2000 census. Kayenta is located immediately south of Monument Valley and contains a number of hotels and motels which service visitors to the...
- List of dinosaur-bearing rock formations
External links
{{coord missing|Arizona}}