My Public Lands Magazine, Summer 2014 (13969734272)

Red Gulch Dinosaur Tracksite is an assemblage of fossil

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

footprints on public land near

Shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses ** Thin-shell structure Science Biology * Seashell, a hard o ...

, in

Big Horn County, Wyoming Big Horn County is a county in the U.S. state of Wyoming. As of the 2020 United States Census, the population was 11,521. The county seat is Basin. Its north boundary abuts the south boundary of Montana. History Big Horn County was created by ...

. They were discovered in 1997 by Erik P. Kvale, a research geologist from the Indiana Geological Survey. The site is managed by the

Bureau of Land Management The Bureau of Land Management (BLM) is an agency within the United States Department of the Interior responsible for administering federal lands. Headquartered in Washington DC, and with oversight over , it governs one eighth of the country's la ...

as part of the Red Gulch/Alkali National Back Country Byway and is open to the public.

Fossils

The fossilized tracks are believed to have been made during the

Middle Jurassic The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations co ...

Period, 160-180 million years b.p., on what was then a shore of the

Sundance Sea The Sundance Sea was an epeiric sea that existed in North America during the mid-to-late Jurassic Period of the Mesozoic Era. It was an arm of what is now the Arctic Ocean, and extended through what is now western Canada into the central western ...

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 ...

tracks are thought to be among those discovered, but evidence suggests that the tracks were made by a large, diverse group of dinosaurs. Due to a rarity of Middle Jurassic theropods, the species that made the tracks is currently unknown. The majority of the footprints are in the area dubbed "the ballroom". Besides the trackways, a variety of fossils can be found, including

belemnite Belemnitida (or the belemnite) is an extinct order of squid-like cephalopods that existed from the Late Triassic to Late Cretaceous. Unlike squid, belemnites had an internal skeleton that made up the cone. The parts are, from the arms-most to ...

crinoid Crinoids are marine animals that make up the class Crinoidea. Crinoids that are attached to the sea bottom by a stalk in their adult form are commonly called sea lilies, while the unstalked forms are called feather stars or comatulids, which are ...

s, and shrimp burrows.

Geology

The tracksite is in a

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

layer in the lower part of the Sundance Formation. Its discovery was somewhat surprising, since the Sundance was historically considered to be marine in nature. Indeed, the layer just above the tracksite contains abundant marine fossils including numerous ''

Gryphaea ''Gryphaea'', one of the genera known as devil's toenails, is a genus of extinct oysters, marine bivalve mollusks in the family Gryphaeidae. These fossils range from the Triassic period to the middle Paleogene period, but are mostly restric ...

nebrascensis'', indicating that later in the Jurassic it was once again submerged.

References

External links

BLM Wyoming.gov: official Red Gulch Dinosaur Tracksite website
*
BLM Wyoming.gov: "Red Gulch Dinosaur Tracksite, An Ancient Shoreline Comes to Light"
*

* ttp://life.bio.sunysb.edu/~crnoto/Wyoming%202004/11.html State University of New York at Stony Brook.edu: Red Gulch Dinosaur Tracksite photo gallery {{authority control Fossil trackways in the United States Fossil parks in the United States Jurassic geology of Wyoming Jurassic paleontological sites of North America Paleontology in Wyoming 1997 in paleontology Protected areas of Big Horn County, Wyoming Bureau of Land Management areas in Wyoming

Fossils

Geology

See also

References

External links