Paleontology in Oregon

The location of the state of Oregon

Paleontology in Oregon refers to paleontological research occurring within or conducted by people from the U.S. state of Oregon. Oregon was probably submerged under seawater during the early Paleozoic era, but no rocks are known from the Cambrian to Silurian to verify this likelihood. From the Devonian to the Permian, an island chain formed in the state. Coral reefs formed in their vicinity and a rich flora greened the local terrestrial environments. Oregon remained mostly covered in seawater throughout the Mesozoic. Local wildlife would come to include marine invertebrates and ichthyosaurs. Terrestrial life included pterosaurs and dinosaurs.

During the early Cenozoic era the state was still mostly covered in seawater, but local sea levels began to rise and fall. On land, the local forests would come to be inhabited by creatures like bear dogs, camels, cats, deer, gomphotheres, and horses. The local climate gradually cooled and a variety of habitats like forests, arid plains and savannahs. Relatives of modern elephants lived in the state.

Local Native Americans devised myths to explain fossils. By the mid-19th century local fossils had come to the attention of formally trained scientists. Notable local finds include the John Day Fossil Beds, the only fossil crocodile known west of the Rockies, fossil bear footprints, and a plesiosaur skeleton. The Eocene dawn redwood Metasequoia occidentalis is the Oregon state fossil.

Prehistory

No Precambrian fossils are known from Oregon, so the state's fossil record does not begin until the Paleozoic.[1] No rocks are known in Oregon from the Cambrian to the Silurian, although the state was probably submerged by the sea.[1] From the Devonian to the Permian a chain of volcanic islands began forming in the state. These islands were home to lagoons and surrounded by coral reefs. Brachiopods also inhabited the nearby waters. Plant fossils suggest a rich terrestrial flora was not far away.[1] Oregon remained mostly covered in seawater throughout the Mesozoic. Local marine invertebrate life included corals, oysters, and snails. Local vertebrates included ichthyosaurs and pterosaurs.[1] Although it has been claimed that no dinosaurs are known to have inhabited Oregon,[2] fossils of a possible hadrosaurid ("duck-billed" dinosaur) were discovered in the southwestern corner of the state, believed to be Campanian in age.[3] During the Cretaceous period, between 90 and 100 million years ago, most of Oregon was covered by the ocean.[4] Plesiosaurs swam and fed on the fish of this Oregonian ocean.[4]

Oregon remained partially covered by the sea into the Cenozoic. Contemporary marine life included fig and turret-shelled snails.[1] During the Tertiary, Oregon trees like Alniphyllum, ash, beech, cinnamon, Gargura, hemlock, hickory, hornbeam, oak, persimmon, pine, redwood, and sycamore grew in Oregon.[5] Alders were also present.[1] The most common local trees were the redwoods and sycamores.[5] The Tertiary petrified wood of Oregon is sometimes partially opalized.[6] Oregon's sea levels fluctuated rapidly during the Eocene to Oligocene interval.[7] Mollusks were diverse in Oregon during the Eocene, with at least 25 species known from the Fern Ridge Dam area.[8] From the Eocene to the Oligocene, the Sunset Highway area was covered in seawater. During this interval it was inhabited by invertebrates like crinoids, crustaceans, echinoderms, gastropods, and scaphopods.[9] Local Eocene sharks left their teeth behind in the Rocky Point Quarry to the west of the Nehalem River.[10] Crocodiles lived in Oregon from 60 to 45 million years ago.[9] The local flora from this interval also left behind remains that would later fossilize.[9] As the Cenozoic proceeded, the climate of Oregon became cooler and drier. Local marine life took on a more modern aspect. These were inhabited by creatures like bear dogs, camels, cats, deer, gomphotheres, and horses. Local mountain building added the Cascade and Coast ranges to the local topography.[1] Oligocene crinoids were preserved near Vernonia.[10] During the early Oligocene, Oregon's terrestrial environments were home to Cinnamomum, cycads, palms, the primitive sycamore Platanophyllum angustilobus, and walnuts. The plant fossil sites to the east of Clarno's Ferry are one of the few places in the world where the fruits, leaves, and wood, of prehistoric plants were preserved in a single location.[11] Late Oligocene fossil salamanders were preserved near north Goshen.[8] During the Oligocene and Miocene, volcanic eruption-emitted clouds of ash buried many animals.[9] During the Pleistocene, mountains developed icy caps. A variety of environments filled the flatter areas of the state. Among these were arid plains, forests, and savannahs. Volcanic eruptions occurred sporadically in the Cascade Mountains throughout the rest of the Cenozoic.[1] During the Pleistocene, relatives of modern elephants left behind teeth and fragmentary skeletal remains in the Spencer Creek area and other parts of the Willamette Valley.[12]

History

Indigenous interpretations

Many Native American peoples believe it is bad luck to uncover fossils from their place of burial. One group (probably the Modoc) expected future misfortune when one white paleontologist (possibly Edward Drinker Cope) took Pleistocene mammal remains from the Willamette River near the ghost town of Bethel. Local lore attributes these fossils to water monsters killed early in history by Coyote.[13] Ancient people living near Fossil collected fossils as far back as 11,000 years ago and kept them at a dwelling that has since been uncovered by archeologists.[14] Some of the fossils kept there were pierced to be made into jewelry. Five slabs of rock bearing leaf impressions were found neatly stacked in the corner of the site.[15]

Scientific research

Arctotherium.

Paleontology in Oregon has a long history.[9] In 1861, a company of soldiers that arrived in Fort Dalles after visiting the Crooked River region brought back fossil bones and teeth, among which was a well-preserved rhinoceros jaw. The find brought instant fame to the John Day region of Oregon as a source of fossils.[9] The pastor of the fort's Congregational church, Thomas Condon, happened to be an enthusiast of geology and paleontology.[16] In 1862, some soldiers were dispatched with supplies to Harney Valley. Condon went along with them and prospected for fossils when the troops passed back through the Crooked River area. He went fossil collecting again in 1863 and discovered rich fossil deposits north of Picture Gorge in the John Day River valley. He realized that he had stumbled on a find of major scientific importance. Since he himself had no scientific qualifications or references to use in identifying fossils, Condon sent some fossils to O. C. Marsh of Yale University. Marsh replied with a request for Condon to guide an expedition to the area in which he found the fossils. Condon obliged and over the ensuing years a series of fossil hunting expeditions ventured into the John Day fossil beds. Fossils uncovered during these excavations ended up in a wide variety of prestigious museums like the American Museum of Natural History and Smithsonian Institution.[17] In 1962, two University of Oregon students discovered 35 bones fragments and fifteen teeth. These remains were left by an ancient crocodile that lived 60 to 45 million years ago. The specimen was the only known fossil crocodile found west of the Rocky Mountains and has been considered one of the most significant fossil finds of the mid-to-late twentieth century in Oregon.[9] In 1980, Pleistocene bear fossil footprints were reported from Lake County. The 9-meter trackway consists of footprints up to 40 cm long. This suggests a body size similar to the largest modern bears. These are among the few known Pleistocene fossil footprints in the western United States.[18] These prints were likely left by Arctotherium, the only known mammal of the age who could account for them.[19]

Modern dawn redwood foliage.

More recently, during the summer of 2004, amateur paleontologists Mike Kelly and Greg Kovalchuk were looking for invertebrate fossils on public land in the grey hills of the central region of the state. Kelly examined a rock that turned out to preserve a tooth. The fossil hunters examined the area around the fossil and found several more teeth downslope from the original. Although they knew the find was important they both knew collecting vertebrate fossils on public land was a crime. So, they took down the fossil's GPS coordinates. They alerted the Paleontology Program Coordinator of the Bureau of Land Management for Washington and Oregon, John Zancanella. Kelly and Kovalchuk agreed to meet Zancanella at the site to verify the fossil's location. After relocating the remains, the Bureau of Land Management arranged for the Curator of the Vertebrate Paleontology of the Museum of Geology at the South Dakota School of Mines, Dr. James E. Martin, to excavate the fossils.[4] Martin is a prominent marine reptile researcher.[4] Kelly and Kovalchuk had discovered the lower jaw of a plesiosaur, roughly three feet long. The discovery was only the third vertebrate fossil from the late Mesozoic era in the entire Pacific Northwest. It was also the region's first plesiosaur. The fossil was set to be curated by South Dakota's Museum of Geology, with a replica intended to be displayed locally to help educate the public about the region's fossils.[4] Zancanella described Kelly and Kovalchuk's conduct throughout their discovery as "exemplary" and concluded that they "did everything right".[4] In 2005, the Eocene dawn redwood Metasequoia occidentalis was designated the Oregon state fossil.

Protected areas

Natural history museums

See also

Footnotes

  1. 1 2 3 4 5 6 7 8 Fremd, Retallack, Springer, and Scotchmoor (2005); "Paleontology and geology".
  2. ↑ Madin "3. Early Sediments: Oregon's first coast".
  3. ↑ Weishampel DB, et al. (2004) "Dinosaur Distribution". The Dinosauria, eds Weishampel DB, Dodson P, Osmólska H. University of California Press, Berkeley, CA, Second Ed, pp 575–582.
  4. 1 2 3 4 5 6 Gibbons, Zancanella, and Strebig (2005); "Amateur Paleontologists Find Rare Fossil".
  5. 1 2 Murray (1974); "Oregon", pages 244-245.
  6. ↑ Murray (1974); "Oregon", page 244.
  7. ↑ Murray (1974); "Oregon", page 240.
  8. 1 2 Murray (1974); "Oregon", page 241.
  9. 1 2 3 4 5 6 7 Murray (1974); "Oregon", page 237.
  10. 1 2 Murray (1974); "Oregon", page 239.
  11. ↑ Murray (1974); "Oregon", page 245.
  12. ↑ Murray (1974); "Oregon", page 242.
  13. ↑ Mayor (2005); "Pretty Shield and the Medicine Skull", page 283.
  14. ↑ Mayor (2005); "Note 51", page 390.
  15. ↑ Mayor (2005); "Note 51", pages 390-391.
  16. ↑ Murray (1974); "Oregon", pages 237-238.
  17. ↑ Murray (1974); "Oregon", page 238.
  18. ↑ Lockley and Hunt (1999); "Mammoths of the Pleistocene", page 275.
  19. ↑ Lockley and Hunt (1999); "Mammoths of the Pleistocene", pages 275-276.

References

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