 |
| Sadlerochit Formation | |
|---|---|
| Stratigraphic range: Permian | |
 Sadlerochit Group, geologic column | |
| Type | Formation |
| Location | |
| Region | Alaska |
| Country | United States |
The Sadlerochit Formation is a geologic formation in Alaska. It preserves fossils dating back to the Permian period.[ citation needed ]
Pachyrhinosaurini is a tribe of centrosaurine dinosaurs. The clade existed during the Late Cretaceous, about 83.6 to 68.5 million years ago, evolving during the early Campanian, and becoming extinct in the Maastrichtian. The tribe contains five genera: Styracosaurus, Stellasaurus, Einiosaurus, Achelousaurus, and Pachyrhinosaurus. Pachyrhinosaurus and Achelousaurus form the clade of pachyrhinosaurins called the Pachyrostra ("thick-snouts"), characterized primarily by their nasal bosses.
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.
The Staniukovich Formation is a geologic formation in Alaska. It preserves fossils dating back to the Cretaceous period.
The Okpikruak Formation is a geologic formation in Alaska. It preserves fossils dating back to the Cretaceous period.
The Cantwell Formation is a geologic formation in Alaska. It preserves fossils dating back to the Cretaceous period, it has also yielded numerous dinosaur tracks at Denali National Park. Contemporary therizinosaurid and hadrosaurid trackways in the formation indicate that the area was once a major point of immigration between Asia and North America during the Late Cretaceous for many families of dinosaur. Fossil plants similar to water lilies found in the same area suggest the area was a wetland or marsh, with ponds and other large standing bodies of water.
The Chignik Formation is a geologic formation in Alaska. It preserves fossils dating back to the Cretaceous period.
The Chisana Formation is a geologic formation in Alaska. It preserves fossils dating back to the Cretaceous period.
The Corwin Formation is a geologic formation in Alaska. It preserves fossils dating back to the Cretaceous period.
The Skajit Formation is a geologic formation in Alaska. It preserves fossils dating back to the Devonian period.
The Bowser Formation is a geologic formation in Alaska. It preserves fossils dating back to the Jurassic period.
The Chinitna Formation is a geologic formation in Alaska. It preserves fossils dating back to the Jurassic period.
The Tiglukpuk Formation is a geologic formation in Alaska. It preserves fossils dating back to the Jurassic period.
The Sagavanirktok Formation is a geologic formation in Alaska. It preserves fossils dating back to the Neogene period.
The Tyonek Formation is a geologic formation in Alaska. It preserves fossils dating back to the Neogene period.
The Bear Lake Formation is a geologic formation in Alaska. It preserves fossils dating back to the Miocene period.
The Poul Creek Formation is a geologic formation in Alaska. It preserves fossils dating back to the Paleogene period.
The Takhandit Formation is a geologic formation in Alaska. It preserves fossils dating back to the Permian period.
The Heceta Limestone is a geologic formation in Alaska. It preserves fossils dating back to the Silurian period.
The Road River Formation is a geologic formation in Alaska. It preserves fossils dating back to the Silurian period.
The Otuk Formation is a geologic formation in Alaska. It preserves fossils dating back to the Triassic period.
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