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Mesa

From Wikipedia, the free encyclopedia
This article is about the geological formation. For other uses, seeMesa (disambiguation).
Aerial view of mesas inMonument Valley,on theColorado Plateau

Amesais an isolated, flat-toppedelevation,ridgeorhill,which is bounded from all sides by steepescarpmentsand stands distinctly above a surroundingplain.Mesas characteristically consist of flat-lying softsedimentary rockscapped by a more resistant layer or layers of harderrock,e.g.shalesoverlain bysandstones.The resistant layer acts as a caprock that forms the flat summit of a mesa. Thecaprockcan consist of either sedimentary rocks such as sandstone andlimestone;dissectedlava flows;or a deeply erodedduricrust.Unlikeplateau,whose usage does not imply horizontal layers ofbedrock,e.g.Tibetan Plateau,the termmesaapplies exclusively to the landforms built of flat-lyingstrata.Instead, flat-topped plateaus are specifically known astablelands.[1][2][3]

Cockburn Range,Kimberley,Western Australia,Australia

Names, definition and etymology[edit]

As noted by geologist Kirk Bryan in 1922, mesas "...stand distinctly above the surrounding country, as a table stands above the floor upon which it rests".[4]It is from this appearance that the term mesa was adopted from theSpanishwordmesa,meaning "table".[2]

A mesa is similar to, but has a more extensivesummitarea than abutte.There is no agreed size limit that separates mesas from either buttes or plateaus. For example, the flat-topped mountains which are known as mesas in the Cockburn Range ofNorth Western Australiahave areas as large as 350 km2(140 sq mi). In contrast, flat topped hills with areas as small as 0.1 km2(0.039 sq mi) in theElbe Sandstone Mountains,Germany,are described as mesas.[1][2][3]

Less strictly, a very broad, flat-topped, usually isolated hill or mountain of moderate height bounded on at least one side by a steep cliff or slope and representing an erosion remnant also have been called mesas.[3]

In the English-language geomorphic and geologic literature, other terms for mesa have also been used.[1]For example, in the Roraima region of Venezuela, the traditional name,tepui,from the local Pomón language, and the termtable mountainshave been used to describe local flat-topped mountains.[5][6]Similar landforms in Australia are known astablehills,table-top hills,tent hills,orjump ups(jump-ups).[7][8][9]The German termTafelberghas also been used in the English scientific literature in the past.[10]

Formation[edit]

Har Qatum, a mesa located on the southern edge ofMakhtesh Ramon,Israel

Mesas form byweatheringanderosionof horizontally layered rocks that have been uplifted bytectonicactivity. Variations in the ability of different types of rock to resist weathering and erosion cause the weaker types of rocks to be eroded away, leaving the more resistant types of rocks topographically higher than their surroundings.[11]This process is called differential erosion. The most resistant rock types includesandstone,conglomerate,quartzite,basalt,chert,limestone,lava flowsandsills.[11]Lava flows and sills, in particular, are very resistant to weathering and erosion, and often form the flat top, orcaprock,of a mesa. The less resistant rock layers are mainly made up ofshale,a softer rock thatweathersanderodesmore easily.[11]

The differences in strength of various rock layers are what give mesas their distinctive shape. Less resistant rocks are eroded away on the surface into valleys, where they collect water drainage from the surrounding area, while the more resistant layers are left standing out.[11]A large area of very resistant rock, such as a sill, may shield the layers below it from erosion while the softer rock surrounding it is eroded into valleys, thus forming a caprock.

Differences in rock type also reflect on the sides of a mesa, as instead of smooth slopes, the sides are broken into a staircase pattern called "cliff-and-bench topography".[11]The more resistant layers form the cliffs, or stairsteps, while the less resistant layers form gentle slopes, or benches, between the cliffs. Cliffs retreat and are eventually cut off from the main cliff, orplateau,by basal sapping. When the cliff edge does not retreat uniformly but instead is indented byheadward erodingstreams, a section can be cut off from the main cliff, forming a mesa.[11]

Basal sapping occurs as water flowing around the rock layers of the mesa erodes the underlying soft shale layers, either assurface runofffrom the mesa top or fromgroundwatermoving through permeable overlying layers, which leads toslumpingand flowage of the shale.[12]As the underlying shale erodes away, it can no longer support the overlying cliff layers, which collapse and retreat. When the caprock has caved away to the point where only little remains, it is known as abutte.

Examples and locations[edit]

Australia[edit]

Mount Conner,a mesa located in Northern Territory, Australia
Amadiya,Iraq, a city in its entirety built on a mesa

Czech Republic[edit]

France[edit]

Germany[edit]

India[edit]

Iraq[edit]

Ireland[edit]

Israel[edit]

Italy[edit]

United Kingdom[edit]

England[edit]

Ingleboroughin North Yorkshire, England

Scotland[edit]

United States[edit]

Many but not all American mesas lie within theBasin and Range Province.

Arizona[edit]

Arkansas[edit]

California[edit]

Colorado[edit]

Mount Garfield,a mesa in Colorado

Nevada[edit]

Oklahoma[edit]

Texas[edit]

Utah[edit]

Wisconsin[edit]

On Mars[edit]

A mesa inNoctis LabyrinthusonMars,viewed byHiRISE

A transitional zone onMars,known asfretted terrain,lies between highly cratered highlands and less cratered lowlands. The younger lowland exhibits steep walled mesas andknobs.The mesa and knobs are separated by flat lying lowlands. They are thought to form from ice-facilitated mass wasting processes from ground or atmospheric sources. The mesas and knobs decrease in size with increasing distance from the highland escarpment. The relief of the mesas range from nearly 2 km (1.2 mi) to 100 m (330 ft) depending on the distance they are from the escarpment.[28]

See also[edit]

  • Amba– Steep-sided, flat-topped mountain in Ethiopia, usually harboring various settlement
  • Archipelago– Collection of islands
  • Butte– Isolated hill with steep, often vertical sides and a small, relatively flat top
  • Dissected plateau– Plateaus area that has been severely eroded so that the relief is sharp
  • Mensa– Flat-topped prominence with cliff-like edges
  • Mesa Verde National Park– U.S. national park in Colorado
  • Nor'Wester Mountains– Mountain range in Ontario, Canada – Group of mountains immediately south of Thunder Bay, Ontario, Canada
  • Pingdingshan– prefecture-level city in Henan, China– Chinese city named after a local mesa
  • Potrero– Long mesa that at one end slopes upward to higher terrain
  • Table hill– Raised landform with a flat top
  • Table Mountain– Flat-topped mountain overlooking the city of Cape Town, South Africa
  • Tepui– Table-top mountain or mesa in the Guiana Highlands of South America
  • Tundra– Biome where plant growth is hindered by frigid temperatures
  • Tuya– Flat-topped, steep-sided volcano formed when lava erupts through a thick glacier or ice sheet

References[edit]

Wikimedia Commons has media related toMesas.
Look upmesain Wiktionary, the free dictionary.
  1. ^abcDuszyński, F., Migoń, P. and Strzelecki, M.C., 2019.Escarpment retreat in sedimentary tablelands and cuesta landscapes–Landforms, mechanisms and patterns.Earth-Science Reviews,'no. 102890. doi.org/10.1016/j.earscirev.2019.102890
  2. ^abcMigoń, P., 2004a.Mesa.In: Goudie, A.S. (Ed.),Encyclopedia of Geomorphology.Routledge, London, pp. 668.ISBN9780415272988
  3. ^abcNeuendorf, Klaus K.E. Mehl, James P., Jr. Jackson, Julia A.. (2011).Glossary of Geology(5th Edition). American Geosciences Institute.ISBN9781680151787
  4. ^Bryan, K. (1922). "Erosion and Sedimentation in the Papago Country, Arizona".US Geological Survey Bulletin(730): 19–90.
  5. ^Briceño, H.O. and Schubert, C., 1990.Geomorphology of the Gran Sabana, Guayana Shield, southeastern Venezuela.Geomorphology,3(2), pp.125-141.
  6. ^ Doerr, S.H., 1999.Karst-like landforms and hydrology in quartzites of the Venezuelan Guyana shield: Pseudokarst or "real" karst?.Zeitschrift fur Geomorphologie,43(1), pp.1-17.
  7. ^Jack, R.L., 1915.The Geology and prospects of the Region to the South of the Musgrave Ranges, and the Geology of the Western Portion of the Great Australian Artesian Basin.Geol. Survey South Australia Bulletin 5,pp. 72.
  8. ^Macquarie dictionary: Australia's national dictionary online,Macquarie Library, 2021,retrieved11 March2021
  9. ^"Land Zones of Queensland".Queensland Government.2012. pp. 62–63.Retrieved11 March2021.
  10. ^King, L.C., 1942.South African Scenery. A Textbook of Geomorphology.Oliver and Boyd, Edinburgh, London (340 pp.).
  11. ^abcdefEasterbrook, Don J. (1999).Surface Processes and Landforms.Upper Saddle River, NJ:Prentice Hall.ISBN9780138609580.
  12. ^Choreley, Richard J.; Stanley A. Schumm;David E. Sugden(1985).Geomorphology.New York: Methuen.
  13. ^Burbridge, Andrew; Mckenzie, NL; Kenneally, Kevin F (1991).Nature Conservation Reserves in the Kimberley, Western Australia.Department of Conservation and Land Management.ISBN9780646033747.Retrieved4 July2021.
  14. ^Report.The Department. 1966.
  15. ^Kindred by Choice Germans and American Indians Since 1800, Glenn H Penny, 2013
  16. ^Lilienstein – a mesa with a symbolic character
  17. ^abcJancewicz, Kacper."Morphological diversity of mesas in Elbsandsteingebirg".ResearchGate.Retrieved4 July2021.
  18. ^abcJournal of Earth Sciences Royal Dublin Society. (1980). Ireland: The Society.
  19. ^"Masada - Definition, History, Siege & Facts".Encyclopedia Britannica.Retrieved4 July2021.
  20. ^Karst Rock Features. Karren sculpturing: Karren sculpturing.Zalozoba ZRC. 2009. p. 286.ISBN9789612541613.Retrieved4 July2021.
  21. ^Lakeland - The Wildlife of Cumbria, Derek A Ratcliffe
  22. ^abReading, H. G. (1954) The stratigraphy and structure of the syncline of stainmore, Durham theses, Durham University. Available at Durham E-Theses Online:http://etheses.dur.ac.uk/9349/
  23. ^"Bulletin of the Centre of Excellence in Geology".University of Peshawar - Bulletin of the Centre of Excellence in Geology.7–8:3. 1975.
  24. ^abWood, Harold; Preece, Dorothy (1948).Modern Geography...: The British Isles.Retrieved9 July2022.
  25. ^Reid, T.R. (2 November 2000)."A Lord's Leaky Roof vs. a Changing Scotland".The Washington Post.Retrieved10 August2022.
  26. ^National Geographic Encyclopedia (2016)
  27. ^"Floating Mesa, Bushland, Texas".Atlas Obscura.Retrieved19 October2021.
  28. ^Baker, David M. Morphological Analyses of Mesas and Knobs in the Northwest Fretted Terrain of Mars; Constraints on the Presence and Distribution of Ice-Facilitated Mass-Wasting. Ed. Alexander K. Stewart and James W. Head. Vol. 40. Issue 2. pp. 72. United States: Geological Society of America (GSA): Boulder, CO, United States, 2008.
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