The Kaiparowits Formation is a

sedimentary Sedimentary rocks are types of rock (geology), rock that are formed by the accumulation or deposition of mineral or organic matter, organic particles at Earth#Surface, Earth's surface, followed by cementation (geology), cementation. Sedimentati ...

rock formation A rock formation is an isolated, scenic, or spectacular surface rock outcrop. Rock formations are usually the result of weathering and erosion sculpting the existing rock. The term ''rock formation'' can also refer to specific sediment ...

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 a ...

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 199 ...

, in the southern part of

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 it ...

in the western

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. 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. Campanian s ...

in age. This

Upper Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger 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 ''creta'', the ...

formation was formed from

alluvial Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') 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. Alluv ...

floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river which stretches from the banks of its channel to the base of the enclosing valley walls, and which experiences flooding during periods of high discharge.Goudi ...

s of large

river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wate ...

s in coastal southern

Laramidia Laramidia was an island continent that existed during the Late Cretaceous period (99.6–66 Ma), when the Western Interior Seaway split the continent of North America in two. In the Mesozoic era, Laramidia was an island land mass separated from A ...

;

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...

beds A bed is an item 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 (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology. ...

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 preserved ...

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. Most fieldwork has been conducted by The Natural History Museum of Utah.

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 76. ...

. 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 kind of 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 in fact simply be 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 Kaiparowits dates from about 77.3 to 74.9 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 color:DPF bar:NAM2 from:-76.7 till:-76.6 text:

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

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

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

color:DPF bar:NAM4 from:-76.3 till:-76.2 text: Chasmosaurus russelli 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–Esca ...

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, quadrupe ...

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

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

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 a genus of herbivorous ceratopsian dinosaur from the Cretaceous Period (Campanian stage), about 75.5 to 74.5&nb ...

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

Pachyrhinosaurini Pachyrhinosaurini is a tribe (biology), tribe of Centrosaurinae, centrosaurine dinosaurs. The clade existed during the Late Cretaceous, about 84.9 to 68.5 million years ago, evolving during the earliest Campanian, and becoming extinct i ...

sp. color:KWF bar:NAM11 from:-75.8 till:-75.6 text:

Nasutoceratops titusi ''Nasutoceratops'' is an extinct genus of ceratopsian dinosaur. It is a basal Centrosaurinae, centrosaurine which lived during the Late Cretaceous period (geology), Period (late Campanian, about 76.0-75.5 Mya (unit), Ma). Fossils have been found ...

color:DPF bar:NAM12 from:-76.9 till:-76.5 text:

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

color:DPF bar:NAM13 from:-76.4 till:-76.2 text:

Prosaurolophus maximus ''Prosaurolophus'' (; meaning "before '' Saurolophus''", in comparison to the later dinosaur with a similar head crest) is a genus of hadrosaurid (or duck-billed) dinosaur from the Late Cretaceous of North America. It is known from the remains o ...

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 ...

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

color:DPF bar:NAM17 from:-76.9 till:-76.8 text:

Parasaurolophus walkeri ''Parasaurolophus'' (; meaning "near crested lizard" in reference to ''Saurolophus)'' is a genus of herbivorous hadrosaurid ornithopod dinosaur that lived in what is now North America and possibly Asia during the Late Cretaceous Period, about ...

color:DPF bar:NAM18 from:-76.7 till:-76.6 text:

Parasaurolophus ''Parasaurolophus'' (; meaning "near crested lizard" in reference to '' Saurolophus)'' is a genus of herbivorous hadrosaurid ornithopod dinosaur that lived in what is now North America and possibly Asia during the Late Cretaceous Period, abou ...

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

Parasaurolophus cyrtocristatus ''Parasaurolophus'' (; meaning "near crested lizard" in reference to '' Saurolophus)'' is a genus of herbivorous hadrosaurid ornithopod dinosaur that lived in what is now North America and possibly Asia during the Late Cretaceous Period, ab ...

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'' ( , meaning " Lambe's lizard") is a genus of hadrosaurid dinosaur that lived about 75 million years ago, in the Late Cretaceous period (Campanian stage) of North America. This bipedal/quadrupedal, herbivorous dinosaur is kn ...

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

The Kaiparowits Formation is a muddy bed that was deposited between about 77.3 to 74.9 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, and the Western Interior Sea) was a large inland sea that split the continent of North America into two landmasses. The ancient sea, ...

. 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. Specimens were discovered in Utah in the Kaiparowits Formation of the Grand Staircase–Es ...

'', they were for

sexual selection Sexual selection is a mode of natural selection in which members of one biological 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 t ...

Paleofauna

Animals present include

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

(sharks and rays), gars,

bowfin The bowfin (''Amia calva'') is a bony 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 the sole surviving species of the Halecomorphi ...

sturgeons Sturgeon is the common name for the 27 species of fish belonging to the family Acipenseridae. The earliest sturgeon fossils date to the Late Cretaceous, and are descended from other, earlier acipenseriform fish, which date back to the Early ...

frog A frog is any member of a diverse and largely Carnivore, carnivorous group of short-bodied, tailless amphibians composing the order (biology), order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-f ...

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 ten ...

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

lizard Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia alt ...

crocodilia 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 ...

ns (including ''

Deinosuchus ''Deinosuchus'' () is an extinct genus of alligatoroid crocodilian, related to modern alligators and caimans, that lived 82 to 73 million years ago (Ma), during the late Cretaceous period. The name translates as "terrible crocodile" and i ...

''),

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, t ...

theropod 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 c ...

s such as

dromaeosaurid Dromaeosauridae () is a family of feathered theropod dinosaurs. They were generally small to medium-sized feathered carnivores that flourished in the Cretaceous Period. The name Dromaeosauridae means 'running lizards', from Greek ('), meaning ...

troodontids Troodontidae is a clade of bird-like theropod dinosaurs. During most of the 20th century, troodontid fossils were few and incomplete and they have therefore been allied, at various times, with many dinosaurian lineages. More recent fossil discov ...

, and ''

Ornithomimus velox ''Ornithomimus'' (; "bird mimic") is a genus of ornithomimid dinosaurs from the Late Cretaceous Period of what is now North America. ''Ornithomimus'' was a swift bipedal theropod which fossil evidence indicates was covered in feathers, equipped ...

'', armored dinosaurs, the duckbill ''

'', and a variety of early

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

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 any members of the mammalian infraclass Marsupialia. All extant marsupials are endemic to Australasia, Wallacea and the Americas. A distinctive characteristic common to most of these species is that the young are carried in a po ...

s, and

insectivora The 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 Eulipotyphla, w ...

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 of what are now Asia and North America. They are distinct for their characteristically short, beaked, parrot-like skulls, with or wi ...

n ''

Hagryphus giganteus ''Hagryphus'' (meaning " Ha's griffin") is a monospecific genus of caenagnathid dinosaur from southern Utah that lived during the Late Cretaceous (upper Campanian stage, 75.95 Ma) in what is now the Kaiparowits Formation of the Grand Staircase– ...

''.

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, ...

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

Theropods

References

Bibliography

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

Age