Revision 151162 of "ខ្ពង់រាបគោរាជ" on kmwiki

{{main|Isan}}
[[Image:Isaanmountains.svg|thumb|Map of Korat-Basin.]]
'''The Khorat Plateau''' also Korat Plateau, is a plateau in the northeastern (Isan) region of Thailand, named for the short form of [[Nakhon Ratchasima]], an historical [[stronghold]] controlling access to and from the plateau.

==Geography==
The average elevation is 200 m and it covers an area of about 155,000 km². The saucer-shaped plateau is divided by a range of hills called the [[Phu Phan mountains]] into two basins: the northern Sakhon Nakhon Basin, and the southern Khorat Basin. The plateau is tilted towards the south-east, and drained by the [[Mun River|Mun]] and [[Chi river]]s, tributaries to the [[Mekong]] that forms the north eastern boundary of the area. It is separated from [[Central Thailand]] by the [[Phetchabun mountains|Phetchabun mountain range]] and the [[Dong Phaya Yen mountains]] in the west, the [[Sankamphaeng Range]] in the southwest and by the [[Dongrek mountains]] in the south, all of which historically made access to the plateau difficult.

These together with the [[Truong Son Range]] in the north-east catch a lot of the rainfall, so the South-West [[monsoon]] has much lower intensity then in other regions—the mean annual rainfall in Nakhon Ratchasima is about 1150 mm, compared with 1500 mm in Central Thailand. The difference between dry and wet season is much stronger, which makes the area less fertile for [[rice]]. The portion known as [[Tung Kula Rong Hai]] was once exceptionally [[arid]].

==Geology==
{{see|Nam Phong Formation}}
The plateau uplifted from an extensive [[plain]] composed of remnants of the [[Cimmeria (continent)|Cimmerian microcontinent]], and [[terrane]]s such as the [[Shan–Thai Terrane]], either late in the [[Pleistocene]] or early in the [[Holocene]] [[Epoch]],<ref>{{cite journal
| last1        = Bunopas
| first1       = Sangad
| authorlink1  =
| last2        = Vella
| first2       = Paul
| date         = 17&ndash;24 November 1992
| title        = Geotectonics and Geologic Evolution of Thailand
| page         = 224
| location     = Bangkok
| publisher    = National Conference on Geologic Resources of Thailand
| format       =
| url          = http://library.dmr.go.th/library/6198.pdf
| quote        = ...latest Pleistocene early to the Recent regional uplifting must have occurred.
|archiveurl=http://web.archive.org/20110820011502/library.dmr.go.th/library/6198.pdf|archivedate=2011-08-20}}</ref> approximately Year 1 of the  [[Holocene calendar]]. Much of the surface of the plateau was once classified as [[laterite]], and layers that can easily be cut into brick-shaped blocks are still so called, but the classification of [[soil]]s as various types of [[oxisol]]s is more useful for [[agriculture]]. Oxisols of the type called rhodic ferralsols, or [[Yasothon Province|Yasothon]] soils, formed under humid tropical conditions in the early [[Tertiary]]. When portions of the plain uplifted as a plateau, these [[relict]] soils, characterized by a bright red color, wound up on [[Highland (geography)|upland]]s in a great semicircle around the southern rim. These soils overlie associated [[gravel]] [[soil horizon|horizon]]s cleared of [[sand]] by [[field (agriculture)|field]] [[termites]], in a prolonged and still on-going process of [[bioturbation]].  Xanthic ferralsols of the [[Nakhon Ratchasima Province|Khorat]] and [[Ubon Ratchathani Province|Udon]] Series, characterized by a pale yellow to brown color, developed in midlands in processes still under investigation; as are those  forming [[lowland]] soils resembling European [[brown earth|brown soil]]s.<ref>Lofjle & Kubiniok, ''Landform development and bioturbation on the Khorat plateau, Northeast Thailand'', Nat.Hist.Bull.Siam Soc. (56), 1996 [http://www.aseanbiodiversity.info/Abstract/53002297.pdf]</ref>

==Archeology==
Many of the [[Prehistoric Thailand]] sites are sited on the plateau, with some bronze relics of the [[Dong Son culture]] having been found. The [[World Heritage site|World Heritage]] [[Ban Chiang]] archeological site, discovered in 1966, yielded evidence of [[bronze]] making beginning circa 2000 BC, which lacks evidence of weaponry so often associated with the [[Bronze Age]] in Europe and the rest of the world.<ref>{{cite web |url= http://archaeology.about.com/cs/asia/a/banchiang.htm |title= Ban Chiang, Thailand Bronze Age Village and Cemetery |accessdate= 28 Dec 2010 |author= K. Kris Hirst |publisher= About.com
}}</ref> The site appears to have once been part of a broader culture, until abandoned circa 200 AD, not resettled until the early 19th century. None Nok Tha in the [[Phu Wiang District]] of Khon Kaen yielded evidence of an Iron Age settlement dating from 1420 to 50 BC.

The region was once under the [[suzerainty]] of the [[Dvaravati]], and later under that of the [[Khmer Empire]], and is dotted with the ruins of Khmer resthouses located about 15 miles, or a day's [[Walking|walk]], apart, along [[Ancient Khmer Highway|Khmer highway]]s. The chapels  were not just places of rest, but also [[hospice]]s and [[library|libraries]], and typically included a [[baray]] (pond.)<ref>{{cite web
|url= http://thailandculturecustomguide.org/geography-of-thailand/isaan-heartland.html
|title= Isaan heartland
|accessdate= 4 May 2011
|work= Thailand's ancient civilizations
|publisher= Your Guide to Thai Culture
|quote= ''Thailand: Traits and Treasures'', National Identity Board, ©2005 by Office of The Permanent Secretary, The Prime Minister’s Office, ISBN 974-9771-52-4
}}</ref>

==History==
Due to scarcity of information from the periods known as the [[Dark ages of Cambodia]], the plateau seems to have been largely depopulated. In 1718, the first [[Lao people|Lao]] [[muang]] in the [[Chi River|Chi]] valley — and indeed anywhere in the interior of the  Khorat Plateau  — was founded at [[Suwannaphum District]] in present-day [[Roi Et Province]] by an official in the service of King [[Nokasad]] of the [[Kingdom of Champasak]].<ref name=Brow1976 >{{citation
 | last1 = Brow  | first1 = James  | year = 1976
 | title = Population, land and structural change in Sri Lanka and Thailand
 |journal= Contributions to Asian studies
 |volume= |series= |issue= issue 9 |page= 47
 | publisher = Kogan Page
 | isbn = 90-04-04529-5
 | url = http://books.google.co.th/books?id=IiUVAAAAIAAJ&pg=PA47&dq=Suwannaphum&hl=en&sa=X&ei=2HNLT-b6N4irrAeKkLDWDw&ved=0CFQQ6AEwBg
|quote = }}</ref>

==See also==
* [[Bai sema]]
* [[History of Isan]]

==References==
{{reflist}}

==External links==
* [http://www.experiencefestival.com/khorat_plateau Khorat Plateau]: A selection of articles related to Khorat Plateau from Global Oneness.
*[http://www.eoearth.org/article/Northern_Khorat_Plateau_moist_deciduous_forests Northern Khorat Plateau moist deciduous forests]

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[[Category:Plateaus of Thailand|Khorat]]
[[Category:Isan]]
[[Category:Natural regions]]