The Kaiparowits Formation is a

sedimentary Sedimentary rocks are types of rock formed by the cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or deposited at Earth's surface. Sedime ...

rock formation A rock formation is an isolated, scenic, or spectacular surface rock (geology), rock outcrop. Rock formations are usually the result of weathering and erosion sculpting the existing rock. The term ''rock Geological formation, formation ...

found in the

Kaiparowits Plateau Location of the Kaiparowits Plateau within Utah The Kaiparowits Plateau is a large, elevated landform located in southern Utah, in the southwestern United States. Along with the Grand Staircase and the Canyons of the Escalante, it makes up ...

Grand Staircase–Escalante National Monument The Grand Staircase–Escalante National Monument (GSENM) is a United States national monument protecting the Grand Staircase, the Kaiparowits Plateau, and the Canyons of the Escalante (Escalante River) in southern Utah. It was established in 19 ...

, in the southern part of

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 ...

in the western

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

. It is over 2800 feet (850 m) thick, and is

Campanian The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...

in age. This

Upper Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cret ...

formation was formed from

alluvial Alluvium (, ) is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluvium is also sometimes called alluvial deposit. Alluvium is ...

floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high Discharge (hydrolog ...

s of large

river A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of ...

s in coastal southern

Laramidia Laramidia was an island continent that existed during the Late Cretaceous period (99.6–66 Year#SI prefix multipliers, Ma), when the Western Interior Seaway split the continent of North America in two. In the Mesozoic era, Laramidia was an island ...

;

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

beds A bed is a piece of furniture that is used as a place to sleep, rest, and relax. Most modern beds consist of a soft, cushioned mattress on a bed frame. The mattress rests either on a solid base, often wood slats, or a sprung base. Many be ...

are the deposit of rivers, and

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from ''shale'' by its lack of fissility.Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, ...

beds represent floodplain deposits. It is

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

iferous, with most specimens from the lower half of the formation, but exploration is only comparatively recent, with most work being done since 1982. It has been estimated that less than 10% of the Kaiparowits formation has been explored for fossils. The Natural History Museum of Utah has conducted most fieldwork.

Age

Traditionally, the Kaiparowits Formation has been considered to be roughly equivalent in age to the northern

Dinosaur Park Formation The Dinosaur Park Formation is the uppermost member of the Belly River Group (also known as the Judith River Group), a major geologic unit in southern Alberta. It was deposited during the Campanian stage of the Late Cretaceous, between about 7 ...

. This, combined with the differences in fauna between the two formations, has led some scientists, most notably Scott Sampson, to conclude that there was some barrier separating northern and southern Laramidia at this time. However, preliminary re-calibration of late Cretaceous formation correlations suggests that the upper part of the Kaiparowits, where many of the unique species are found, is actually younger than the Dinosaur Park, and that some Kaiparowits species may simply be the descendants of Dinosaur Park species. However, new dates reveal that this is simply an artifact of inaccurate

Ar-Ar dating Arar or Ar-Ar may refer to: Geography and history * Arar, Saudi Arabia, the capital of Al Hudud ash Shamaliyah (The Northern Border) province ** Arar border crossing, a Saudi-Iraqi border crossing near Arar, Saudi Arabia and Nukhayb, Iraq * Arar ...

, and both formations had similar ages. According to new Uranium-Lead stratigraphic data, the fossil-bearing portion of the Kaiparowits Formation dates from about 77.24 to 75.02 million years ago, with the

volcaniclastic Volcaniclastics are geologic materials composed of broken fragments (clasts) of volcanic rock. These encompass all clastic volcanic materials, regardless of what process fragmented the rock, how it was subsequently transported, what environment it ...

Upper Valley Member estimated to date from 73.8 to 72.8 million years ago.

Biostratigraphy

The timeline below follows the re-calibrated timeline of Fowler (2017), showing species from the Kaiparowits Formation in green, and related species from Alberta in blue. ImageSize = width:1000px height:auto barincrement:15px PlotArea = left:10px bottom:50px top:10px right:10px Period = from:-77 till:-74 TimeAxis = orientation:horizontal ScaleMajor = unit:year increment:1 start:-77 ScaleMinor = unit:year increment:1 start:-77 TimeAxis = orientation:hor AlignBars = justify Colors = #legends id:CAR value:claret id:ANK value:rgb(0.4,0.3,0.196) id:BOT value:teal id:KWF value:green id:DPF value:blue id:black value:black id:white value:white id:cretaceous value:rgb(0.675,0.675,0.35) id:jurassic value:rgb(0.753,0.753,0.486) id:triassic value:rgb(0.827,0.827,0.65) id:mesozoic value:rgb(0.54,0.54,0.258) BarData= bar:eratop bar:space bar:periodtop bar:space bar:NAM1 bar:NAM2 bar:NAM3 bar:NAM4 bar:NAM5 bar:NAM6 bar:NAM7 bar:NAM8 bar:NAM9 bar:NAM10 bar:NAM11 bar:NAM12 bar:NAM13 bar:NAM14 bar:NAM15 bar:NAM16 bar:NAM17 bar:NAM18 bar:NAM19 bar:NAM20 bar:NAM21 bar:NAM22 bar:space bar:period bar:space bar:era PlotData= align:center textcolor:black fontsize:M mark:(line,black) width:25 shift:(7,-4) bar:periodtop from: -75.3 till: -74.2 color:cretaceous text:Upper Kaiparowits from: -76.2 till: -75.3 color:jurassic text:Middle Kaiparowits from: -76.8 till: -76.2 color:triassic text:Lower Kaiparowits bar:eratop from: -77 till: -74 color:mesozoic text:Biostratigraphy of the Kaiparowits Formation (green) compared to the Dinosaur Park Formation (blue) PlotData= align:left fontsize:M mark:(line,white) width:5 anchor:till align:left color:DPF bar:NAM1 from:-76.9 till:-76.8 text:

Mercuriceratops gemini ''Mercuriceratops'' is an extinct genus of herbivorous chasmosaurine ceratopsid dinosaur known from the Late Cretaceous (Campanian stage) of Alberta, Canada and Montana, United States. It contains a single species, ''Mercuriceratops gemini''. D ...

color:DPF bar:NAM2 from:-76.7 till:-76.6 text:

Chasmosaurus priscus ''Chasmosaurus'' ( ) is a genus of ceratopsid dinosaur from the Late Cretaceous Period in North America. Its given name means 'opening lizard', referring to the large openings ( fenestrae) in its frill (Greek ''chasma'', meaning 'opening', 'hollo ...

color:DPF bar:NAM3 from:-76.5 till:-76.3 text:

Chasmosaurus belli ''Chasmosaurus'' ( ) is a genus of ceratopsid dinosaur from the Late Cretaceous Period in North America. Its given name means 'opening lizard', referring to the large openings ( fenestrae) in its frill (Greek ''chasma'', meaning 'opening', 'hollo ...

color:DPF bar:NAM4 from:-76.3 till:-76.2 text:

Chasmosaurus russelli ''Chasmosaurus'' ( ) is a genus of ceratopsid dinosaur from the Late Cretaceous Period in North America. Its given name means 'opening lizard', referring to the large openings ( fenestrae) in its frill (Greek ''chasma'', meaning 'opening', 'holl ...

color:DPF bar:NAM5 from:-76.3 till:-76.2 text:

Vagaceratops irvinensis ''Vagaceratops'' (meaning "wandering (''vagus'', Latin) horned face", in reference to its close relationship with ''Kosmoceratops'' from Utah) is a genus of herbivorous ceratopsian dinosaur. It is a chasmosaurine ceratopsian which lived during ...

color:KWF bar:NAM6 from:-76.0 till:-75.9 text:

Kosmoceratops richardsoni ''Kosmoceratops'' () is a genus of ceratopsid dinosaur that lived in North America about 76–75.9 million years ago during the Late Cretaceous period. Specimens were discovered in Utah in the Kaiparowits Formation of the Grand Staircase–Esc ...

color:KWF bar:NAM7 from:-76.0 till:-75.6 text:

Utahceratops gettyi ''Utahceratops'' is an extinct genus of ceratopsian dinosaur that lived approximately 76.4~75.5 million years ago during the Late Cretaceous period in what is now Utah. ''Utahceratops'' was a large-sized, robustly-built, ground-dwelling, quadrup ...

color:DPF bar:NAM8 from:-76.9 till:-76.5 text:

Centrosaurus apertus ''Centrosaurus'' ( ; ) is a genus of centrosaurine ceratopsian dinosaur from Campanian age of Late Cretaceous Canada. Their remains have been found in the Dinosaur Park Formation, dating from 76.5 to 75.5 million years ago. Discovery and nami ...

color:DPF bar:NAM9 from:-76.4 till:-76.2 text:

Styracosaurus albertensis ''Styracosaurus'' ( ; meaning "spiked lizard" from the Ancient Greek / "spike at the butt-end of a spear-shaft" and / "lizard") is an extinct genus of herbivorous ceratopsian dinosaur from the Late Cretaceous (Campanian stage) of North America. ...

color:DPF bar:NAM10 from:-76.0 till:-75.9 text:

Pachyrhinosaurini Centrosaurinae (from the Greek, meaning "pointed lizards") is a subfamily of ceratopsid, a group of large quadrupedal ornithischian dinosaur. Centrosaurine fossil remains are known primarily from the northern region of Laramidia (modern day Alber ...

sp. color:KWF bar:NAM11 from:-75.8 till:-75.6 text: Nasutoceratops titusi color:DPF bar:NAM12 from:-76.9 till:-76.5 text: Gryposaurus notabilis color:DPF bar:NAM13 from:-76.4 till:-76.2 text: Prosaurolophus maximus color:DPF bar:NAM14 from:-76.5 till:-76.0 text:

Gryposaurus ''Gryposaurus'' (meaning "hooked-nosed (Ancient Greek, Greek ''grypos'') lizard"; sometimes incorrectly translated as "griffin (Latin ''gryphus'') lizard") was a genus of hadrosaur, duckbilled dinosaur that lived about 80 to 75 million years ag ...

sp. color:KWF bar:NAM15 from:-76.5 till:-75.8 text:

sp. color:KWF bar:NAM16 from:-75.6 till:-75.5 text: Gryposaurus monumentensis color:DPF bar:NAM17 from:-76.9 till:-76.8 text: Parasaurolophus walkeri color:DPF bar:NAM18 from:-76.7 till:-76.6 text:

Parasaurolophus ''Parasaurolophus'' (; meaning "beside crested lizard" in reference to ''Saurolophus'') is a genus of hadrosaurid "duck-billed" dinosaur that lived in what is now western North America and possibly Asia during the Late Cretaceous period, a ...

sp. color:KWF bar:NAM19 from:-76.4 till:-75.5 text:

Parasaurolophus cyrtocristatus ''Parasaurolophus'' (; meaning "beside crested lizard" in reference to ''Saurolophus'') is a genus of Hadrosauridae, hadrosaurid "duck-billed" dinosaur that lived in what is now Laramidia, western North America and possibly Asia during the L ...

color:DPF bar:NAM20 from:-76.9 till:-76.5 text: Corythosaurus casuarius color:DPF bar:NAM21 from:-76.6 till:-76.3 text:

Lambeosaurus lambei ''Lambeosaurus'' ( ) is a genus of hadrosaurid dinosaur that lived during the Late Cretaceous period of western North America. The first skull of ''Lambeosaurus'' found was used by palaeontologist Lawrence M. Lambe to justify the creation of t ...

color:DPF bar:NAM22 from:-76.2 till:-76.1 text: Lambeosaurus magnicristatus PlotData= align:center textcolor:black fontsize:M mark:(line,black) width:25 bar:period from: -76.9 till: -75.8 color:cretaceous text:Dinosaur Park Formation, Alberta from: -75.8 till: -75.2 color:cretaceous text:Bearpaw Formation, Alberta from: -75.2 till: -74 color:cretaceous text:Horseshoe Canyon Formation, Alberta

Habitat

Teratophoneus attacking Kosmoceratops-transformed

The Kaiparowits Formation is a muddy bed that was deposited between about 77.3 to 72.8 million years ago, in the area where the

is today. It is extremely fossil rich, with thousands of plants and animal fossils being preserved in amongst its sandstone and mudstone deposits. Based on plants remains including multiple vines, leaves, and branches, It was assumed by paleontologists Scott Sampson and his colleagues that Utah in the

was a dense jungle bordering the

Western Interior Seaway The Western Interior Seaway (also called the Cretaceous Seaway, the Niobraran Sea, the North American Inland Sea, or the Western Interior Sea) was a large inland sea (geology), inland sea that existed roughly over the present-day Great Plains of ...

. The jungle theory would also support why almost all the animals in the Kaiparowits Formation were new species, and why the deposits were so plentiful. Without the need for herbivores to migrate to find food, and theropods to migrate after herbivores, a whole ecosystem could evolve secluded from interbreeding. The theory also supported why the dinosaurs adorned such features like the 15 horns of ''

Kosmoceratops ''Kosmoceratops'' () is a genus of ceratopsid dinosaur that lived in North America about 76–75.9 million years ago during the Late Cretaceous period (geology), period. Specimens were discovered in Utah in the Kaiparowits Formation of the Gran ...

'', they were for

sexual selection Sexual selection is a mechanism of evolution in which members of one sex mate choice, choose mates of the other sex to mating, mate with (intersexual selection), and compete with members of the same sex for access to members of the opposite sex ...

Paleofauna

Animals present include

chondrichthyans Chondrichthyes (; ) is a class of jawed fish that contains the cartilaginous fish or chondrichthyans, which all have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or ''bony fish'', which have skeletons ...

(sharks and rays), gars,

bowfin The ruddy bowfin (''Amia calva'') is a ray-finned fish native to North America. Common names include mudfish, mud pike, dogfish, grindle, grinnel, swamp trout, and choupique. It is regarded as a relict, being one of only two surviving species ...

sturgeons Sturgeon (from Old English ultimately from Proto-Indo-European language, Proto-Indo-European *''str̥(Hx)yón''-) is the common name for the 27 species of fish belonging to the family Acipenseridae. The earliest sturgeon fossils date to the ...

frog A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough ski ...

salamander Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All t ...

turtle Turtles are reptiles of the order (biology), order Testudines, characterized by a special turtle shell, shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Crypt ...

lizard Lizard is the common name used for all Squamata, squamate reptiles other than snakes (and to a lesser extent amphisbaenians), encompassing over 7,000 species, ranging across all continents except Antarctica, as well as most Island#Oceanic isla ...

crocodilia Crocodilia () is an order of semiaquatic, predatory reptiles that are known as crocodilians. They first appeared during the Late Cretaceous and are the closest living relatives of birds. Crocodilians are a type of crocodylomorph pseudosuchia ...

ns (including ''

Deinosuchus ''Deinosuchus'' is an extinct genus of eusuchian, either an Alligatoroidea, alligatoroid Crocodilia, crocodilian or a stem-group crocodilian, which lived during the Late Cretaceous around . The first remains were discovered in North Carolina ...

''),

pterosaur Pterosaurs are an extinct clade of flying reptiles in the order Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cretaceous (228 million to 66 million years ago). Pterosaurs are the earli ...

coelurosauria Coelurosauria (; from Greek, meaning "hollow-tailed lizards") is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. Coelurosauria is a subgroup of theropod dinosaurs that includes compsognathids, tyra ...

theropod Theropoda (; from ancient Greek , (''therion'') "wild beast"; , (''pous, podos'') "foot"">wiktionary:ποδός"> (''pous, podos'') "foot" is one of the three major groups (clades) of dinosaurs, alongside Ornithischia and Sauropodom ...

s such as

dromaeosaurid Dromaeosauridae () is a family (biology), family of feathered coelurosaurian Theropoda, theropod dinosaurs. They were generally small to medium-sized feathered carnivores that flourished in the Cretaceous period (geology), Period. The name Drom ...

troodontids Troodontidae is a clade of bird-like theropod dinosaurs from the Late Jurassic to Late Cretaceous. During most of the 20th century, troodontid fossils were few and incomplete and they have therefore been allied, at various times, with many dinos ...

, and ''

Ornithomimus velox ''Ornithomimus'' (; "bird mimic") is a genus of Ornithomimosauria, ornithomimid Theropoda, theropod dinosaurs from the Campanian and Maastrichtian ages of Late Cretaceous Laramidia, Western North America. ''Ornithomimus'' was a swift, bipedal din ...

'', armored dinosaurs, the duckbill ''

'', and a variety of early

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

s including

multituberculate Multituberculata (commonly known as multituberculates, named for the multiple tubercles of their teeth) is an extinct order of rodent-like mammals with a fossil record spanning over 130 million years. They first appeared in the Middle Jurassic, a ...

marsupial Marsupials are a diverse group of mammals belonging to the infraclass Marsupialia. They are natively found in Australasia, Wallacea, and the Americas. One of marsupials' unique features is their reproductive strategy: the young are born in a r ...

s, and

insectivora The Order (biology), order Insectivora (from Latin ''insectum'' "insect" and ''vorare'' "to eat") is a now-abandoned biological grouping within the class of mammals. Some species have now been moved out, leaving the remaining ones in the order ...

ns. Recent finds include large specimens of the duckbill ''

'', including the species ''G. monumentensis'', and the first described remains of the

oviraptorosauria Oviraptorosaurs ("egg thief lizards") are a group of feathered maniraptoran dinosaurs from the Cretaceous Period (geology), Period of what are now Asia and North America. They are distinct for their characteristically short, beaked, parrot-like s ...

n '' Hagryphus giganteus''.

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 ...

s are also known from the Kaiparowits, including an excellently preserved hadrosaur skin impression known from a recent analysis by Herrero and Farke.

Turtles

Neosuchians

Ornithischians

Ankylosaurs

Ceratopsians

Ornithopods

Theropods

References

Bibliography

* {{Grand Staircase–Escalante National Monument Geologic formations of Utah Upper Cretaceous Series of North America Cretaceous geology of Utah Mudstone formations of the United States Sandstone formations of the United States Fluvial deposits Paleontology in Utah Grand Staircase–Escalante National Monument

Age