Purgatoire River track site

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One of the dinosaur trackways at the Purgatoire River track site. PurgatoireTrackwayCO.jpg
One of the dinosaur trackways at the Purgatoire River track site.
Theropod footprint at the Purgatoire River dinosaur track site, Picket Wire Canyonlands, Colorado, U.S.A. AllosaurusFootprintCO.jpg
Theropod footprint at the Purgatoire River dinosaur track site, Picket Wire Canyonlands, Colorado, U.S.A.
Interp Panel 1 Largest Dinosaur Tracksite in North America.jpg
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Interp Panel 2 Life at Dinosaur Lake.jpg
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Interp Panel 3 Aerial Image of Purgatoire Tracksite.jpg
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The Purgatoire River track site, also called the Picketwire Canyonlands tracksite, is one of the largest dinosaur tracksites in North America. [1] The site is located on public land of the Comanche National Grassland, along the Purgatoire ("Picketwire") River south of La Junta in Otero County, Colorado.

Contents

In 2014 researchers published information about the discovery of a new area containing 90 trackways. These paralleled existing trackways of sauropods. This observation confirmed the major finding of these studies, that the sauropods displayed gregarious behavior. [2]

The tracksite is far from paved roads, but accessible to the public by hiking on foot, by mountain bike, or by horseback. Motorized vehicle access is restricted to tours conducted by the US Forest Service. [3]

In 2001, the first discoveries in the Picketwire Canyonlands area were made of related fossil dinosaur bones. Fieldwork has continued each year on recovery of the massive bones of a sauropod (brontosaur) skeleton. The project has been supported by volunteers and the Sternberg Museum of Natural History of western Kansas. [4] Continued exploration of fossils in the canyonlands has revealed tetrapods. This finding had major implications for understanding of geology in the area. As a result, researchers in 2012 proposed a "major revision of lower Mesozoic stratigraphy in the Picket Wire Canyonlands" and a "critical reappraisal of understanding of the correlation of Triassic strata from Wyoming, through and under the Denver Basin, to the High Plains of Oklahoma and New Mexico." [5]

Geology

The more than 100 trackways, made up of more than 1500 individual footprints, were made by both biped and quadruped dinosaurs. The tracks occur in limestone of the Jurassic Morrison Formation. The site formed along the shore of a large freshwater lake at the time the tracks were made. A previously unmapped region was discovered in 2012, where removal of alluvium revealed 90 new trackways, showing parallel prints. [2]

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<span class="mw-page-title-main">Morrison Formation</span> Rock formation in the western United States

The Morrison Formation is a distinctive sequence of Upper Jurassic sedimentary rock found in the western United States which has been the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandstone, siltstone, and limestone and is light gray, greenish gray, or red. Most of the fossils occur in the green siltstone beds and lower sandstones, relics of the rivers and floodplains of the Jurassic period.

<span class="mw-page-title-main">Glen Canyon Group</span> Group of geologic formations in the Colorado Plateau

The 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 called the Glen Canyon Sandstone in the Green River Basin of Colorado and Utah.

<span class="mw-page-title-main">Kayenta Formation</span> Jurassic sandstone formation of southwestern United States

The Kayenta Formation is a geological 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. Traditionally has been suggested as Sinemurian-Pliensbachian, but more recent dating of detrital zircons has yielded a depositional age of 183.7 ± 2.7 Ma, thus a Pliensbachian-Toarcian age is more likely A previous depth work recovered a solid Lower-Middle Pliensbachian age from measurements done in the Tenney Canyon.

<span class="mw-page-title-main">Fossil track</span> Fossilized footprint (ichnite)

A fossil track or ichnite is a fossilized footprint. This is a type of trace fossil. A fossil trackway is a sequence of fossil tracks left by a single organism. Over the years, many ichnites have been found, around the world, giving important clues about the behaviour of the animals that made them. For instance, multiple ichnites of a single species, close together, suggest 'herd' or 'pack' behaviour of that species.

The Ziliujing Formation is a geological formation in China, It is Early Jurassic in age. It is part of the stratigraphy of the Sichuan Basin. The dinosaur Gongxianosaurus and indeterminate theropod material are known from the Dongyuemiao Member of the formation, as well as dinosaur footprints, Zizhongosaurus and indeterminate prosauropods from the Da'anzhai Member. The basal sauropod Sanpasaurus is known from the Maanshan Member. An unnamed stegosaur and the pliosauroid plesiosaur Sinopliosaurus are also known from this formation but they were found an indeterminate member. An unnamed teleosaurid known from a complete skull has also been found in the formation, pending a formal description. The deposition environment during the Da'anzhai Member in the lower Toarcian is thought to have been that of a giant freshwater lake encompassing the whole of the Sichuan basin, around 3 times larger than Lake Superior, coeval with the Toarcian Oceanic Anoxic Event around 183 Ma.

<span class="mw-page-title-main">Dinosaur Ridge</span>

Dinosaur Ridge is a segment of the Dakota Hogback in the Morrison Fossil Area National Natural Landmark located in Jefferson County, Colorado, near the town of Morrison and just west of Denver.

The Uhangri Formation, located at the Uhangri Dinosaur Fossil Site, is a geological formation from which fossil pterosaur tracks have been recovered near Haenam-eup, Jeollanam-do, South Korea.

<span class="mw-page-title-main">Martin Lockley</span> Welsh palaeontologist

Martin G. Lockley is a Welsh palaeontologist. He was educated in the United Kingdom where he obtained degrees and post-doctoral experience in Geology in the 1970s. Since 1980 he has been a professor at the University of Colorado at Denver, (UCD) and is currently a Professor Emeritus. He is best known for work on fossil footprints and was former director of the Dinosaur Tracks Museum at UCD. He is an Associate Curator at the University of Colorado Museum of Natural History and Research Associate at the Denver Museum of Nature and Science. During his years at UCD he earned a BA in 2007 in Spanish with a minor in Religious Studies, became a member of the Scientific and Medical Network and taught and published on the evolution of consciousness.

The Calcários Micríticos da Serra de Aire is a Bathonian geologic formation in Portugal. Fossil sauropod tracks have been reported from the formation.

<i>Parabrontopodus</i> Dinosaur footprint

Parabrontopodus is an ichnogenus of dinosaur footprint, that was initially described by Lockley et al. in 1994, and was assigned to Sauropoda by Lockley in 2002 and in 2004 by Niedzwiedzki and Pienkowski. Various species through their footprints that are characterized by the association of two impressions left by hand and foot. The acquisition of a specific family is complex, but now in most cases, they have been considered diplodocoids and similar animals. The reason is that their traces left are large, but in proportion to the size, from animals, seem very light because the depth of imprint is low.

<span class="mw-page-title-main">Paleontology in Arkansas</span>

Paleontology in Arkansas refers to paleontological research occurring within or conducted by people from the U.S. state of Arkansas. The fossil record of Arkansas spans from the Ordovician to the Eocene. Nearly all of the state's fossils have come from ancient invertebrate life. During the early Paleozoic, much of Arkansas was covered by seawater. This sea would come to be home to creatures including Archimedes, brachiopods, and conodonts. This sea would begin its withdrawal during the Carboniferous, and by the Permian the entire state was dry land. Terrestrial conditions continued into the Triassic, but during the Jurassic, another sea encroached into the state's southern half. During the Cretaceous the state was still covered by seawater and home to marine invertebrates such as Belemnitella. On land the state was home to long necked sauropod dinosaurs, who left behind footprints and ostrich dinosaurs such as Arkansaurus.

<span class="mw-page-title-main">Paleontology in Texas</span>

Paleontology in Texas refers to paleontological research occurring within or conducted by people from the U.S. state of Texas. Author Marian Murray has remarked that "Texas is as big for fossils as it is for everything else." Some of the most important fossil finds in United States history have come from Texas. Fossils can be found throughout most of the state. The fossil record of Texas spans almost the entire geologic column from Precambrian to Pleistocene. Shark teeth are probably the state's most common fossil. During the early Paleozoic era Texas was covered by a sea that would later be home to creatures like brachiopods, cephalopods, graptolites, and trilobites. Little is known about the state's Devonian and early Carboniferous life. However, evidence indicates that during the late Carboniferous the state was home to marine life, land plants and early reptiles. During the Permian, the seas largely shrank away, but nevertheless coral reefs formed in the state. The rest of Texas was a coastal plain inhabited by early relatives of mammals like Dimetrodon and Edaphosaurus. During the Triassic, a great river system formed in the state that was inhabited by crocodile-like phytosaurs. Little is known about Jurassic Texas, but there are fossil aquatic invertebrates of this age like ammonites in the state. During the Early Cretaceous local large sauropods and theropods left a great abundance of footprints. Later in the Cretaceous, the state was covered by the Western Interior Seaway and home to creatures like mosasaurs, plesiosaurs, and few icthyosaurs. Early Cenozoic Texas still contained areas covered in seawater where invertebrates and sharks lived. On land the state would come to be home to creatures like glyptodonts, mammoths, mastodons, saber-toothed cats, giant ground sloths, titanotheres, uintatheres, and dire wolves. Archaeological evidence suggests that local Native Americans knew about local fossils. Formally trained scientists were already investigating the state's fossils by the late 1800s. In 1938, a major dinosaur footprint find occurred near Glen Rose. Pleurocoelus was the Texas state dinosaur from 1997 to 2009, when it was replaced by Paluxysaurus jonesi after the Texan fossils once referred to the former species were reclassified to a new genus.

<span class="mw-page-title-main">Paleontology in Wyoming</span> Research on extinct life in Wyoming

Paleontology in Wyoming includes research into the prehistoric life of the U.S. state of Wyoming as well as investigations conducted by Wyomingite researchers and institutions into ancient life occurring elsewhere. The fossil record of the US state of Wyoming spans from the Precambrian to recent deposits. Many fossil sites are spread throughout the state. Wyoming is such a spectacular source of fossils that author Marian Murray noted in 1974 that "[e]ven today, it is the expected thing that any great museum will send its representatives to Wyoming as often as possible." Murray has also written that nearly every major vertebrate paleontologist in United States history has collected fossils in Wyoming. Wyoming is a major source of dinosaur fossils. Wyoming's dinosaur fossils are curated by museums located all over the planet.

<span class="mw-page-title-main">Paleontology in Colorado</span> Paleontological research in the U.S. state of Colorado

Paleontology in Colorado refers to paleontological research occurring within or conducted by people from the U.S. state of Colorado. The geologic column of Colorado spans about one third of Earth's history. Fossils can be found almost everywhere in the state but are not evenly distributed among all the ages of the state's rocks. During the early Paleozoic, Colorado was covered by a warm shallow sea that would come to be home to creatures like brachiopods, conodonts, ostracoderms, sharks and trilobites. This sea withdrew from the state between the Silurian and early Devonian leaving a gap in the local rock record. It returned during the Carboniferous. Areas of the state not submerged were richly vegetated and inhabited by amphibians that left behind footprints that would later fossilize. During the Permian, the sea withdrew and alluvial fans and sand dunes spread across the state. Many trace fossils are known from these deposits.

<span class="mw-page-title-main">Paleontology in New Mexico</span>

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<span class="mw-page-title-main">Paleontology in Utah</span> Paleontological research in Utah

Paleontology in Utah refers to paleontological research occurring within or conducted by people from the U.S. state of Utah. Utah has a rich fossil record spanning almost all of the geologic column. During the Precambrian, the area of northeastern Utah now occupied by the Uinta Mountains was a shallow sea which was home to simple microorganisms. During the early Paleozoic Utah was still largely covered in seawater. The state's Paleozoic seas would come to be home to creatures like brachiopods, fishes, and trilobites. During the Permian the state came to resemble the Sahara desert and was home to amphibians, early relatives of mammals, and reptiles. During the Triassic about half of the state was covered by a sea home to creatures like the cephalopod Meekoceras, while dinosaurs whose footprints would later fossilize roamed the forests on land. Sand dunes returned during the Early Jurassic. During the Cretaceous the state was covered by the sea for the last time. The sea gave way to a complex of lakes during the Cenozoic era. Later, these lakes dissipated and the state was home to short-faced bears, bison, musk oxen, saber teeth, and giant ground sloths. Local Native Americans devised myths to explain fossils. Formally trained scientists have been aware of local fossils since at least the late 19th century. Major local finds include the bonebeds of Dinosaur National Monument. The Jurassic dinosaur Allosaurus fragilis is the Utah state fossil.

The Bell Ranch Formation is a Late Jurassic (Kimmeridgian) geologic formation in eastern and northeastern New Mexico and the western Oklahoma panhandle. Fossil theropod tracks have been reported from the formation.

<span class="mw-page-title-main">20th century in ichnology</span>

The 20th century in ichnology refers to advances made between the years 1900 and 1999 in the scientific study of trace fossils, the preserved record of the behavior and physiological processes of ancient life forms, especially fossil footprints. Significant fossil trackway discoveries began almost immediately after the start of the 20th century with the 1900 discovery at Ipolytarnoc, Hungary of a wide variety of bird and mammal footprints left behind during the early Miocene. Not long after, fossil Iguanodon footprints were discovered in Sussex, England, a discovery that probably served as the inspiration for Sir Arthur Conan Doyle's The Lost World.

<span class="mw-page-title-main">John Foster (paleontologist)</span> American paleontologist

John Russell Foster is an American paleontologist. Foster has worked with dinosaur remains from the Late Jurassic of the Colorado Plateau and Rocky Mountains, as well as working on Cambrian age trilobite faunas in the southwest region of the American west. He named the crocodiliform trace fossil Hatcherichnus sanjuanensis in 1997 and identified the first known occurrence of the theropod trace fossil Hispanosauropus in North America in 2015.

This article records new taxa of trace fossils of every kind that are scheduled to be described during the year 2019, as well as other significant discoveries and events related to trace fossil paleontology that are scheduled to occur in the year 2019.

References