Paleontology in Alaska

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The location of the state of Alaska Alaska in United States (US50).svg
The location of the state of Alaska

Paleontology in Alaska refers to paleontological research occurring within or conducted by people from the U.S. state of Alaska. During the Late Precambrian, Alaska was covered by a shallow sea that was home to stromatolite-forming bacteria. Alaska remained submerged into the Paleozoic era and the sea came to be home to creatures including ammonites, brachiopods, and reef-forming corals. An island chain formed in the eastern part of the state. Alaska remained covered in seawater during the Triassic and Jurassic. Local wildlife included ammonites, belemnites, bony fish and ichthyosaurs. Alaska was a more terrestrial environment during the Cretaceous, with a rich flora and dinosaur fauna.

Contents

During the early Cenozoic, Alaska had a subtropical environment. The local seas continued to drop until a land bridge connected the state with Asia. Early humans crossed this bridge and remains of contemporary local wildlife such as woolly mammoths often show signs of having been butchered.

More recent Native Americans interpreted local fossils through a mythological lens. The local fossils had attracted the attention of formally trained scientists by the 1830s. Major local finds include the Kikak-Tegoseak Pachyrhinosaurus bonebed. The Pleistocene-aged woolly mammoth, Mammuthus primigenius is the Alaska state fossil.

Prehistory

During the Late Precambrian, Alaska was covered by a shallow sea. This sea was home to bacteria and stromatolites that would later fossilize. Most of the state continued to be submerged by the sea. By this time Alaska was home to brachiopods and trilobites. During the ensuing Ordovician and Silurian a chain of volcanic islands occupied what is now the eastern part of the state. These islands originated as a result of contemporary local tectonism. Coral reefs formed in the seas around these islands. The northern third of Alaska was still covered by seawater from the Devonian to the Permian. Local marine life included ammonites, brachiopods, corals, and gastropods. [1] At least 34 different species of gastropods lived in Alaska during the late Paleozoic. Of these, 9 were completely new to science when first discovered. [2]

During the Triassic, the sea expanded. Northern Alaska was submerged under deep water. Southern Alaska was under a shallow sea. The state's Triassic sea was home to bony fish, ichthyosaurs, and mollusca. Volcanic episodes happened frequently in the state at this time. [1] Volcanism continued into the Jurassic as Alaska experienced a period of relative geologic upheaval. Areas of the state remained inundated by the sea. This sea was home to ammonites and crinoids. [1] In the middle Jurassic most of the mountain ranges characterizing modern Alaska began to form. [3] Alaska's Middle Jurassic Callovian deposits are part of a large geologic region spreading down through Canada and even into the Lower 48 states including Montana, Idaho, North Dakota, Utah and New Mexico. [4] From the mid to late Jurassic, the area now occupied by Snug Harbor was home to a great diversity of marine invertebrates, which left behind a plethora of fossils. Among these were ammonites. [2] Others include belemnites, the gastropod Amberlya , the pelecypods Lima , Oxytoma , and possibly Astarte and Isocyprina . [2]

Woolly mammoths. Woolly mammoth (Mammuthus primigenius) - Mauricio Anton.jpg
Woolly mammoths.

Cretaceous Alaska gained additional landmass due to collisions with other tectonic plates. Local mountain building resulted in the formation of the Brooks Range and other topographic features. Some areas of Alaska were covered by the sea and others were dry land. [1] There were at least 5 species of Inoceramus in Alaska during the Cretaceous period. This was a widespread genus in Alaska and its fossil remains have been discovered in hundreds of different places. [5] Other Cretaceous shellfish were preserved at what is now Umiat Mountain. [6] More than 235 species of plants are known to have grown in Alaska during the Cretaceous, most of which were cycads. [7] Their remains are scattered across hundreds of sites. Among the finds were algae, Ampelopsis , conifers, elm, Ficus , a great diversity of hepaticae, laurel, magnolia, oaks, Pinus , Platanus , and sequoias. Invertebrate remains were also found with the plants. [8] Pieces of Cretaceous amber have been found on the shore of Nelson Island, which is located in the Bering Sea. [9] Dinosaurs lived in Alaska during the Cretaceous. [1]

Alaska remained tectonically active into the Cenozoic era. Volcanism produced the Aleutian Islands. [1] During the Eocene, Alaska's plants resembled those today growing in the temperate, subtropical and tropical regions of earth today. Their remains were preserved in locations such as the Alaska Peninsula, Awik, the Cook Inlet's shoreline, Eagle City, Unga Island. [8] Alaska's late Miocene fossil record also documents the state's ancient invertebrates. [6] From the Miocene to the Pliocene, Alaska's land area just about reached its full modern extent. [3] Alaska's late Pliocene fossils record also documents the state's invertebrates of that age. [6] During periods of low sea level a land bridge connected Alaska and Asia, allowing an exchanged of the continents' wildlife. Significant areas of Alaska were covered by glaciers during the Quaternary. Alaska was also the site of continued volcanic activity. [1] In Alaska, Pleistocene mammal remains are often associated with artifacts left by Folsom people. [9] Geologically recent invertebrate fossils are also known from Alaska. [6]

History

Indigenous interpretations

The Quugaarpaq is a tusked monster from Yup'ik folklore reported to burrow underground. Fresh air was said to be deadly for the Quugaarpaq, mere contact with which would cause it to petrify. These stories are based on fossils of Ice Age proboscideans whose buried remains are sometimes discovered eroding out of the sediment during spring in southeastern Alaska. Many other indigenous cultures from around the world have interpreted proboscidean fossils as the remains of colossal burrowing animals. [10]

Scientific research

Since 1836, at least five discoveries of mammoths have been made in Alaska. One of the earliest occurred in 1897 when mammoth bones were discovered in a volcanic cave on St. Paul Island. This location was regarded as so unusual that some researchers had expressed suspicions that the remains were planted there as a practical joke. [9] In 1850, another major paleontological milestone in the state was reached with what was probably the first publication on the state's Tertiary plants. [3] Alaska's Tertiary plant fossils were first discovered in places such as the Alaska Peninsula, the Cook Inlet's shoreline, and Unga Island. [8] Between 1902 and 1908, hundreds of sources for Cretaceous plant fossils were discovered. Among the finds were algae, Ampelopsis , conifers, elm, Ficus , a great diversity of hepaticae, laurel, magnolia, oaks, Pinus , Platanus , and sequoias. Invertebrate remains were also found with the plants. [8] In 1903, several sources of Tertiary plant fossils were discovered between Awik and Eagle City. [8] In the 1930s, several lengthy scientific papers shed even more light on Alaska's Cretaceous flora. As such, Alaska's Cretaceous plants did not receive serious treatment in the scientific literature until 50 years after its Tertiary flora. [3] No more mammoth remains were found until 1952 when a partially fossilized mammoth tooth was discovered. The specimen weighed 3 pounds and 11 ounces while measuring in at 9.75 inches long. [9] In the mid-to-late twentieth century, the University of Michigan sent summer expeditions into Alaska to look for Cenozoic vertebrates, but after three failed attempts they called off the effort. [11]

Pachyrhinosaurus. Pachyrhinosaurus BW.jpg
Pachyrhinosaurus .

In 1994, a duck-billed dinosaur was discovered in a quarry being excavated in the middle Turonian Matanuska Formation for road material near the Glenn Highway, about 150 miles northeast of Anchorage. [12] This specimen, dubbed the "Talkeetna Mountains Hadrosaur", was the first associated skeleton of an individual dinosaur in Alaska and originated within a previously unknown source of high-latitude dinosaur fossils. [13] That same fall, paleontologists began excavating the specimen, with further work performed during the summer of 1996. [14] It is currently housed at the University of Alaska Museum. [14] The Talkeetna Mountains paleontologists were able to determine that the Talkeetna Mountains Hadrosaur was a juvenile about 3 meters (10 feet) long, [15] but the specimen did not preserve enough anatomical detail for researchers to tell if it was a hadrosaurid or lambeosaurid. [16]

Another 1994 discovery was made by a University of Alaska paleontological survey prospecting along the banks of the Colville River. [17] The team found fossils along the river bank at the base of a bluff that was over 100 meters tall, but could not pinpoint their exact stratigraphic origin on the bluff. [17] In 1997, D. W. Norton and a University of Alaska student named Ron Mancil traced the fossils to the top 3 meters of the bluff. [17] From 1998 to 2002, the Museum of Nature and Science collaborated with the University of Alaska in a typical paleontological excavation of the site, which is now known as the Kikak-Tegoseak Quarry of the Prince Creek Formation. [18] The excavation uncovered a new dinosaur bone bed predominated by the remains of an undetermined species of Pachyrhinosaurus . [19] The United States Army provided assistance to the researchers in 2002. [17] The harsh local climate left the quarry's fossils in a fragmentary state, necessitating that the researchers change their approach to the excavation. [17] After preparing a new approach, workers restarted active excavation in 2005 and stopped at the end of the 2007 field season. [17] The material was removed from the quarry on a sling attached to a U.S. Army Bell 206 Jet Ranger. [17] The fossils are being held at the Museum of Science and Nature. [17]

Natural history museums

Footnotes

  1. 1 2 3 4 5 6 7 Gangloff, Rieboldt, Scotchmoor, Springer (2006); "Paleontology and geology".
  2. 1 2 3 Murray (1974); "Alaska", page 90.
  3. 1 2 3 4 Murray (1974); "Alaska", page 87.
  4. Murray (1974); "Alaska", pages 91–92.
  5. Murray (1974); "Alaska", pages 89–90.
  6. 1 2 3 4 Murray (1974); "Alaska", page 89.
  7. Murray (1974); "Alaska", pages 87–88.
  8. 1 2 3 4 5 Murray (1974); "Alaska", page 88.
  9. 1 2 3 4 Murray (1974); "Alaska", page 91.
  10. Mayor (2005); "The Monsters", pages 123–124.
  11. Murray (1974); "Alaska", page 92.
  12. For date and discovery details, see Pasch and May (2001); "Introduction", page 220. For age, see Pasch and May (2001); "Age of the Bone-Bearing Unit", page 220. For location, see Pasch and May (2001); "Location and Geologic Setting", page 220. For origins within the Matanuska Formation, see Pasch and May (2001); "Abstract", page 219.
  13. Pasch and May (2001); "Abstract", page 219.
  14. 1 2 Pasch and May (2001); "Introduction", page 220.
  15. Pasch and May (2001); "Hadrosaur Skeletal Material from the Talkeetna Mountains", page 223.
  16. Pasch and May (2001); "Hadrosaur Skeletal Material from the Talkeetna Mountains", pages 223–224.
  17. 1 2 3 4 5 6 7 8 Fiorillo, et al. (2010); "Introduction", page 457.
  18. For excavation information, see Fiorillo, et al. (2010); "Introduction", page 457. For the quarry's position in the Prince Creek Formation, see Fiorillo, et al. (2010); "Geologic Setting", page 457.
  19. For the quarry's status as a bonebed, see Fiorillo, et al. (2010); "Introduction", page 457. For the identity of the fossils, see Fiorillo, et al. (2010); "Abstract", page 456
  20. Wild-Eyed Alaska: Gull Island in Kachemak Bay

Related Research Articles

The Matanuska Formation consists of more than 3 km (1.9 mi) of sedimentary strata exposed in the northern Chugach Mountains, Matanuska Valley, and southern Talkeetna Mountains of South-Central Alaska. The Matanuska Formation contains strata from Early Cretaceous (Albian) to Late Cretaceous (Maestrichtian). Parts of the formation contain abundant marine mollusks, foraminifera, and radiolaria. Fossils of non-marine plants are found in some beds. Fossils of two dinosaurs have been recovered from marine mudstones in the formation. The lower Matanuska Formation (MF) is several hundred meters thick and includes non-marine and marine sediments. Campanian-Maastrichtian graded sandstone, conglomerate, and mudstone comprise the upper 2000 meters of the Formation.

Prince Creek Formation

The Prince Creek Formation is a geological formation in Alaska with strata from the early Campanian stage of the Upper Cretaceous to the Danian of the Paleocene, between 80 and 62 million years ago. Dinosaur remains are among the fossils that have been recovered from the formation.

Paleontology in North Carolina

Paleontology in North Carolina refers to paleontological research occurring within or conducted by people from the U. S. state of North Carolina. Fossils are common in North Carolina. According to author Rufus Johnson, "almost every major river and creek east of Interstate 95 has exposures where fossils can be found". The fossil record of North Carolina spans from Eocambrian remains that are 600 million years old, to the Pleistocene 10,000 years ago.

Paleontology in Virginia

Paleontology in Virginia refers to paleontological research occurring within or conducted by people from the U.S. state of Virginia. The geologic column in Virginia spans from the Cambrian to the Quaternary. During the early part of the Paleozoic, Virginia was covered by a warm shallow sea. This sea would come to be inhabited by creatures like brachiopods, bryozoans, corals, and nautiloids. The state was briefly out of the sea during the Ordovician, but by the Silurian it was once again submerged. During this second period of inundation the state was home to brachiopods, trilobites and entire reef systems. During the mid-to-late Carboniferous the state gradually became a swampy environment.

Paleontology in Tennessee

Paleontology in Tennessee refers to paleontological research occurring within or conducted by people from the U.S. state of Tennessee. During the early part of the Paleozoic era, Tennessee was covered by a warm, shallow sea. This sea was home to brachiopods, bryozoans, cephalopods, corals, and trilobites. Tennessee is one of the best sources of Early Devonian fossils in North America. During the mid-to-late Carboniferous, the state became a swampy environment, home to a rich variety of plants including ferns and scale trees. A gap in the local rock record spans from the Permian through the Jurassic. During the Cretaceous, the western part of the state was submerged by seawater. The local waters were home to more fossil gastropods than are known from anywhere else in the world. Mosasaurs and sea turtles also inhabited these waters. On land the state was home to dinosaurs. Western Tennessee was still under the sea during the early part of the Cenozoic. Terrestrial portions of the state were swampy. Climate cooled until the Ice Age, when the state was home to Camelops, horses, mammoths, mastodons, and giant ground sloths. The local Yuchi people told myths of giant lizard monsters that may have been inspired by fossils either local or encountered elsewhere. In 1920, after local fossils became a subject of formal scientific study, a significant discovery of a variety of Pleistocene creatures was made near Nashville. The Cretaceous bivalve Pterotrigonia thoracica is the Tennessee state fossil.

Paleontology in Delaware

Paleontology in Delaware refers to paleontological research occurring within or conducted by people from the U.S. state of Delaware. There are no local rocks of Precambrian, Paleozoic, Triassic, or Jurassic age, so Delaware's fossil record does not begin until the Cretaceous period. As the Early Cretaceous gave way to the Late Cretaceous, Delaware was being gradually submerged by the sea. Local marine life included cephalopods like Belemnitella americana, and marine reptiles. The dwindling local terrestrial environments were home to a variety of plants, dinosaurs, and pterosaurs. Along with New Jersey, Delaware is one of the best sources of Late Cretaceous dinosaur fossils in the eastern United States. Delaware was still mostly covered by sea water through the Cenozoic era. Local marine life included manatees, porpoises, seals, and whales. Delaware was worked over by glaciers during the Ice Age. The Cretaceous belemnite Belemnitella americana is the Delaware state fossil.

Paleontology in New Jersey

Paleontology in New Jersey refers to paleontological research in the US state of New Jersey. The state is especially rich in marine deposits.

Paleontology in Georgia (U.S. state)

Paleontology in Georgia refers to paleontological research occurring within or conducted by people from the U.S. state of Georgia. During the early part of the Paleozoic, Georgia was largely covered by seawater. Although no major Paleozoic discoveries have been uncovered in Georgia, the local fossil record documents a great diversity of ancient life in the state. Inhabitants of Georgia's early Paleozoic sea included corals, stromatolites, and trilobites. During the Carboniferous local sea levels dropped and a vast complex of richly vegetated delta formed in the state. These swampy deltas were home to early tetrapods which left behind footprints that would later fossilize. Little is known of Triassic Georgia and the Jurassic is absent altogether from the state's rock record. During the Cretaceous, however, southern Georgia was covered by a sea that was home to invertebrates and fishes. On land, the tree Araucaria grew, and dinosaurs inhabited the state. Southern Georgia remained submerged by shallow seawater into the ensuing Paleogene and Neogene periods of the Cenozoic era. These seas were home to small coral reefs and a variety of other marine invertebrates. By the Pleistocene the state was mostly dry land covered in forests and grasslands home to mammoths and giant ground sloths. Local coal mining activity has a history of serendipitous Carboniferous-aged fossil discoveries. Another major event in Georgian paleontology was a 1963 discovery of Pleistocene fossils in Bartow County. Shark teeth are the Georgia state fossil.

Paleontology in Arkansas

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.

Paleontology in Iowa

Paleontology in Iowa refers to paleontological research occurring within or conducted by people from the U.S. state of Iowa. The paleozoic fossil record of Iowa spans from the Cambrian to Mississippian. During the early Paleozoic Iowa was covered by a shallow sea that would later be home to creatures like brachiopods, bryozoans, cephalopods, corals, fishes, and trilobites. Later in the Paleozoic, this sea left the state, but a new one covered Iowa during the early Mesozoic. As this sea began to withdraw a new subtropical coastal plain environment which was home to duck-billed dinosaurs spread across the state. Later this plain was submerged by the rise of the Western Interior Seaway, where plesiosaurs lived. The early Cenozoic is missing from the local rock record, but during the Ice Age evidence indicates that glaciers entered the state, which was home to mammoths and mastodons.

Paleontology in Minnesota

Paleontology in Minnesota refers to paleontological research occurring within or conducted by people from the U.S. state of Minnesota. The geologic record of Minnesota spans from Precambrian to recent with the exceptions of major gaps including the Silurian period, the interval from the Middle to Upper Devonian to the Cretaceous, and the Cenozoic. During the Precambrian, Minnesota was covered by an ocean where local bacteria ended up forming banded iron formations and stromatolites. During the early part of the Paleozoic era southern Minnesota was covered by a shallow tropical sea that would come to be home to creatures like brachiopods, bryozoans, massive cephalopods, corals, crinoids, graptolites, and trilobites. The sea withdrew from the state during the Silurian, but returned during the Devonian. However, the rest of the Paleozoic is missing from the local rock record. The Triassic is also missing from the local rock record and Jurassic deposits, while present, lack fossils. Another sea entered the state during the Cretaceous period, this one inhabited by creatures like ammonites and sawfish. Duckbilled dinosaurs roamed the land. The Paleogene and Neogene periods of the ensuing Cenozoic era are also missing from the local rock record, but during the Ice Age evidence points to glacial activity in the state. Woolly mammoths, mastodons, and musk oxen inhabited Minnesota at the time. Local Native Americans interpreted such remains as the bones of the water monster Unktehi. They also told myths about thunder birds that may have been based on Ice Age bird fossils. By the early 19th century, the state's fossil had already attracted the attention of formally trained scientists. Early research included the Cretaceous plant discoveries made by Leo Lesquereux.

Paleontology in North Dakota

Paleontology in North Dakota refers to paleontological research occurring within or conducted by people from the U.S. state of North Dakota. During the early Paleozoic era most of North Dakota was covered by a sea home to brachiopods, corals, and fishes. The sea briefly left during the Silurian, but soon returned, until once more starting to withdraw during the Permian. By the Triassic some areas of the state were still under shallow seawater, but others were dry and hot. During the Jurassic subtropical forests covered the state. North Dakota was always at least partially under seawater during the Cretaceous. On land Sequoia grew. Later in the Cenozoic the local seas dried up and were replaced by subtropical swamps. Climate gradually cooled until the Ice Age, when glaciers entered the area and mammoths and mastodons roamed the local woodlands.

Paleontology in Nebraska

Paleontology in Nebraska refers to paleontological research occurring within or conducted by people from the U.S. state of Nebraska. Nebraska is world-famous as a source of fossils. During the early Paleozoic, Nebraska was covered by a shallow sea that was probably home to creatures like brachiopods, corals, and trilobites. During the Carboniferous, a swampy system of river deltas expanded westward across the state. During the Permian period, the state continued to be mostly dry land. The Triassic and Jurassic are missing from the local rock record, but evidence suggests that during the Cretaceous the state was covered by the Western Interior Seaway, where ammonites, fish, sea turtles, and plesiosaurs swam. The coasts of this sea were home to flowers and dinosaurs. During the early Cenozoic, the sea withdrew and the state was home to mammals like camels and rhinoceros. Ice Age Nebraska was subject to glacial activity and home to creatures like the giant bear Arctodus, horses, mammoths, mastodon, shovel-tusked proboscideans, and Saber-toothed cats. Local Native Americans devised mythical explanations for fossils like attributing them to water monsters killed by their enemies, the thunderbirds. After formally trained scientists began investigating local fossils, major finds like the Agate Springs mammal bone beds occurred. The Pleistocene mammoths Mammuthus primigenius, Mammuthus columbi, and Mammuthus imperator are the Nebraska state fossils.

Paleontology in Oklahoma

Paleontology in Oklahoma refers to paleontological research occurring within or conducted by people from the U.S. state of Oklahoma. Oklahoma has a rich fossil record spanning all three eras of the Phanerozoic Eon. Oklahoma is the best source of Pennsylvanian fossils in the United States due to having an exceptionally complete geologic record of the epoch. From the Cambrian to the Devonian, all of Oklahoma was covered by a sea that would come to be home to creatures like brachiopods, bryozoans, graptolites and trilobites. During the Carboniferous, an expanse of coastal deltaic swamps formed in areas of the state where early tetrapods would leave behind footprints that would later fossilize. The sea withdrew altogether during the Permian period. Oklahoma was home a variety of insects as well as early amphibians and reptiles. Oklahoma stayed dry for most of the Mesozoic. During the Late Triassic, carnivorous dinosaurs left behind footprints that would later fossilize. During the Cretaceous, however, the state was mostly covered by the Western Interior Seaway, which was home to huge ammonites and other marine invertebrates. During the Cenozoic, Oklahoma became home to creatures like bison, camels, creodonts, and horses. During the Ice Age, the state was home to mammoths and mastodons. Local Native Americans are known to have used fossils for medicinal purposes. The Jurassic dinosaur Saurophaganax maximus is the Oklahoma state fossil.

Paleontology in Texas

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.

Paleontology in Montana

Paleontology in Montana refers to paleontological research occurring within or conducted by people from the U.S. state of Montana. The fossil record in Montana stretches all the way back to the Precambrian. During the Late Precambrian, western Montana was covered by a warm, shallow sea where local bacteria formed stromatolites and bottom-dwelling marine life left tracks on the sediment that would later fossilize. This sea remained in place during the early Paleozoic, although withdrew during the Silurian and Early Devonian, leaving a gap in the local rock record until its return. This sea was home to creatures including brachiopods, conodonts, crinoids, fish, and trilobites. During the Carboniferous the state was home to an unusual cartilaginous fish fauna. Later in the Paleozoic the sea began to withdraw, but with a brief return during the Permian.

Paleontology in New Mexico

Paleontology in New Mexico refers to paleontological research occurring within or conducted by people from the U.S. state of New Mexico. The fossil record of New Mexico is exceptionally complete and spans almost the entire stratigraphic column. More than 3,300 different kinds of fossil organisms have been found in the state. Of these more than 700 of these were new to science and more than 100 of those were type species for new genera. During the early Paleozoic, southern and western New Mexico were submerged by a warm shallow sea that would come to be home to creatures including brachiopods, bryozoans, cartilaginous fishes, corals, graptolites, nautiloids, placoderms, and trilobites. During the Ordovician the state was home to algal reefs up to 300 feet high. During the Carboniferous, a richly vegetated island chain emerged from the local sea. Coral reefs formed in the state's seas while terrestrial regions of the state dried and were home to sand dunes. Local wildlife included Edaphosaurus, Ophiacodon, and Sphenacodon.

Paleontology 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.

Paleontology in Nevada

Paleontology in Nevada refers to paleontological research occurring within or conducted by people from the U.S. state of Nevada. Nevada has a rich fossil record of plants and animal life spanning the past 650 million years of time. The earliest fossils from the state are from Esmeralda County, and are Late Proterozoic in age and represent reefs of photosynthesizing blue-green algae, amongst these reefs were some of the oldest known shells in the fossil record, the Cloudina-fauna. Much of the Proterozoic and Paleozoic fossil story of Nevada is that of a warm, shallow, tropical sea, with a few exceptions towards the Late Paleozoic. As such many fossils across the state are those of marine animals, such as trilobites, brachiopods, bryozoans, honeycomb corals, and horn corals.

Paleontology in California

Paleontology in California refers to paleontologist research occurring within or conducted by people from the U.S. state of California. California contains rocks of almost every age from the Precambrian to the Recent. Precambrian fossils are present but rare in California.

References