Английская Википедия:Camas prairie

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Файл:Camassia-quamash.jpg
Indian Camas
(Camassia quamash)

The name camas prairie refers to several different geographical areas in the western United States which were named for the native perennial camassia or camas. The culturally and scientifically significant of these areas lie within Idaho and Montana. Camas bulbs were an important food source for Native Americans.

Idaho

History

Файл:Nez-perce-chiefs-1899-camas-prairie.jpg
Nez Perce chiefs, 1899

Named for the blue flowering camas—an important food source for all Native Americans in the interior Northwest—the Camas Prairie is a traditional Nez Perce gathering place in north central Idaho.[1]

From the Nez Perce National Historical Park: Camas Prairie is interpreted at a highway pullout on the north side of U.S. Highway 95, about six miles (10 km) south of Grangeville.[2] This large prairie was a Nez Perce gathering place, where camas roots were harvested for thousands of years. Several nontreaty bands gathered at Tolo Lake in early June 1877 in anticipation of moving to the Nez Perce reservation. In response to the forced move and other hostile actions, several young Nez Perce people took actions that precipitated the Nez Perce War.

Camas Prairie is a large area, mostly privately owned, that extends many miles between the Salmon and Clearwater River drainages. Most of the area is agricultural and the northern section is within the Nez Perce Indian Reservation. Similar to the opening of lands in Oklahoma, the U.S. government opened the reservation for white settlement on November 18, 1895. The proclamation had been signed less than two weeks earlier by President Cleveland.[3][4][5][6]

The area was home to the second subdivision of the Camas Prairie Railroad,[7] known as the "railroad on stilts" due to its numerous trestles, most of which were timber. Breakheart Pass, a 1975 film starring Charles Bronson, was filmed on portions of the railroad on the Camas Prairie. The railroad ceased operations in the late 1990s.[8]

For more information:

Communities

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Counties

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Southern Idaho

In southern Idaho, east of Mountain Home, the high plain of Camas County around Fairfield is locally called the "Camas Prairie."[9][10][11]

Protected Areas

Montana

The Camas Prairie covers the floor of the Camas Prairie Basin in Sanders County. This basin is a distinct north–south oriented elliptical basin that is drained by Camas Creek into the Flathead River at Perma, Montana. Both the prairie and basin are surrounded by north-south trending mountain ranges except where Camas Creek drains into the Flathead River.[12][13] The basin is about Шаблон:Convert in dimensions with an area of about Шаблон:Convert.[13][14] The center of this relatively flat basin lies at elevations just below Шаблон:Convert.[15] The basin is bordered by the Salish Mountains on its eastern side and northern end and bordered by the Cabinet Mountains on its western side. These mountains rise above elevations of Шаблон:Convert.[12][13][16]

The Camas Prairie region is sparsely populated and lies within the Flathead Indian Reservation. The two main populated places within this region are Camas (Ktunaxa: ya·qa·kmumaǂki[17]) and Perma (Ktunaxa: kxunamaʔnam[17])[12][13]

Bedrock Geology

The basin in which the Camas Prairie lies is a low-relief valley surrounded by mountains composed of metasedimentary strata that belong to the Prichard Formation of the Belt Supergroup. These strata are intensively folded and thrust faulted. The basin is filled with undifferentiated Cenozoic red, greenish, and bluish siltstone and mudstone and volcanic rock. A few sandy and gravelly beds are also present. These strata outcrop at the surface around the perimeter of the basin. Within the basin, they are cover by Шаблон:Convert of Quaternary deposits that accumulated within glacial Lake Missoula.[12][18]

Quaternary Geology

The Camas Prairie is well-known for the large fields of Late Pleistocene giant current ripples that cover a substantial part of its surface.[19] They were created during one of the many times when glacial Lake Missoula drained when its ice dam failed. From the northern edge of the Camas Basin, the fields of giant current ripples extend south (downcurrent) from four mountain passes that were once submerge inlets into the flooded Camas Basin. Southward, these fields of giant current ripples spread out and merge on the basin floor. These sedimentary bedforms are best seen in aerial images and at low sun angles.[20][21]

These giant current ripples are large-to-very-large, subaqueous gravel dunes and antidunes. Although they once covered a significantly larger area, they cover about Шаблон:Convert of the Camas Prairie basin. The wavelength of these dunes and antidunes ranges from Шаблон:Convert and their height ranges from Шаблон:Convert. They are all two-dimensional, flow transverse, sinuous, sedimentary bedforms. The wavelength and height of these giant current ripples decrease away (downcurrent) from the former inlets. Correspondingly, the size of the gravels comprising them decreases south (downcurrent) from boulder and cobble gravels to pebble gravels. Their foreset bedding is poorly defined and their dip varies from 14 to 23 degrees. In addition to the gravel dunes and antidunes, delta-like, expansion bars accumulated below each of the former subaqueous inlets. They consist of foreset beds that consist of boulder-cobble-pebble gravels.[19][20][21]

The Pleistocene deposits and bedforms in the basin have not been dated using radiometric dating methods. The lack of absolute dates prevents the construction of a reliable geochronology for Lake Missoula lake drainage events in the Camas Prairie basin and correlation of the giant current ripples with bedforms and sedimentary deposits outside of it.[21]

The exposed gravel deposits underlying the giant current ripples at Camas Prairie exhibit at least two beds of gravelly deposits that are indicative of deposition by separate Missoula floods. They are separated by an erosional unconformity with a buried and dismembered calcrete, carbonate soil horizon. The calcrete is Шаблон:Convert thick. It provides empirical evidence of at least two separate periods of giant current ripple activity and associated with separate Missoula Floods that occurred thousands of years apart based the thickness and development of the calcrete.[22][23]

The giant current ripples of the Camas Prairie are analogous to similar giant Pleistocene bedforms described form Channeled Scablands of Washington. They are identical to the giant subaqueous bedrooms that formed on the bottom of Lake Kuray-Chuya during the Altai flood in Siberia, Russia. These giant bedforms, which are rare or unknown outside of theoretical and experimental studies, preserved a unique record of the paleohydraulology of a Missoula Flood associated with the catastrophic emptying of Lake Missoula.[19][20]

See also

References

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External links

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Партнерские ресурсы
Криптовалюты
Магазины
Хостинг
Разное

  1. ↑ Шаблон:Cite news
  2. ↑ Шаблон:Cite web
  3. ↑ Шаблон:Cite news
  4. ↑ Шаблон:Cite news
  5. ↑ Шаблон:Cite news
  6. ↑ Шаблон:Cite news
  7. ↑ Шаблон:Cite news
  8. ↑ Шаблон:Cite web
  9. ↑ 9,0 9,1 9,2 Шаблон:Cite news
  10. ↑ 10,0 10,1 10,2 Шаблон:Cite news
  11. ↑ 11,0 11,1 Шаблон:Cite news
  12. ↑ 12,0 12,1 12,2 12,3 LaFave, J.I., Smith, L.N., and Patton, T.W., 2004. Ground-Water Resources of the Flathead Lake Area: Flathead, Lake, Missoula, and Sanders Counties, Montana. Part A – Descriptive Overview and Water-Quality Data. Montana Ground-Water Assessment Atlas 2. Butte, Montana, Montana Bureau of Mines and Geology. 132 pp.
  13. ↑ 13,0 13,1 13,2 13,3 United States Geological Survey, 1959. Perma Quadrangle Montana 15 Minute Series (Topographic). Reston, Virginia, United States Geological Survey, 1 sheet, scale 1:62,500.
  14. ↑ Harrison, J.E., Griggs, A.B. and Wells, J.D., 1986. Geology and structure map of the Wallace 1° x 2° Quadrangle, Montana and Idaho. U.S. Geological Survey Miscellaneous Investigation Series, Map 1-1509. 21 pp. 2 sheets, scale 1:250,000.
  15. ↑ United States Geological Survey, 1989. Camas Prairie Flathead Indian Reservation 7.5 Minute Series (Topographic). Reston, Virginia, United States Geological Survey, 1 sheet, scale 1:24,000.
  16. ↑ United States Geological Survey, 2014. Markle Quadrangle Montana 7.5-Minute Series (Topographic). Reston, Virginia, United States Geological Survey, 1 sheet, scale 1:24,000.
  17. ↑ 17,0 17,1 Шаблон:Cite web
  18. ↑ Lonn, J.D., Smith, L.N., and McCulloch, R.B., 2007. Geologic map of the Plains 30' x 60' quadrangle, western Montana. Montana Bureau of Mines and Geology Open-File Report 554, 43 pp., 1 sheet, scale 1:100,000.
  19. ↑ 19,0 19,1 19,2 Bohorquez, P., Cañada-Pereira, P., Jimenez-Ruiz, P.J. and del Moral-Erencia, J.D., 2019. The fascination of a shallow-water theory for the formation of megaflood-scale dunes and antidunes. Earth-science reviews, 193, pp.91-108
  20. ↑ 20,0 20,1 20,2 Lee, K., 2009. Catastrophic Flood Features at Camas Prairie, Montana. Department of Geology and Geological Engineering, Colorado School of Mines, Golden, Colorado. 39 pp.
  21. ↑ 21,0 21,1 21,2 Alho, P., Baker, V.R. and Smith, L.N., 2010. Paleohydraulic reconstruction of the largest Glacial Lake Missoula draining(s). Quaternary Science Reviews, 29(23-24), pp. 3067-3078.
  22. ↑ Chambers, R.L., 1971. Sedimentation in glacial Lake Missoula. Masters of Science Thesis, University of Montana, Missoula, Montana.
  23. ↑ Chambers, R.L. and Curry, R.R., 1989. Glacial Lake Missoula: sedimentary evidence for multiple drainages. In Breckenridge, R.M., Atwater, B.F., Baker, V.R., Busacca, A.J., Chambers, R.L., Curry, R.R., Hanson, L.G., Kever, E.P., McDonald, E.V., Stradling, D.F. and Waitt, R.B., eds., Glacial Lake Missoula and the channeled scabland. International Geological Congress, 28th, Guidebook, 300, pp. 3-11. American Geophysical Union Washington DC.
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