Northeast or Isan It is called by its landscape characteristics as Khorat Plateau because it has most of the plateau area starting from the highlands and mountains in the south and west. Until reaching the Mekong River in the north and east with the Phu Phan mountain range as a natural divide The topography of this region is divided into two large plains basins, the upper plains are called “Sakon Nakhon Basin” and the lower plains called “Korat Basin”. Traces of settlement of people have been discovered since the ancient time with the Mekong River, the Mun River, the Chi River, it serves as a connecting route between people in the region and outside communities as evidenced by the life and settlement of the ancients for a long time. As evidenced such as paintings on the walls of caves and cliff sheds, cracking stone tools, including ancient communities scattered in various watersheds, both the Sakon Nakhon basin and the Korat basin.
Northeastern region is a plateau in a shallow basin, collectively referred to as Khorat Plateau is shaped like a cup and a basin in the middle. Slope from the west to the east and border with high mountains. Most of the area is covered with rocks. There is an intermittent layer of gravel, round shale and rock salt. From the geological characteristics and age of the rock Made known that the land of Isaan was in the late Mesozoic Era. This plateau is a large continent plateau, a basin of sediment deposition. Some of the time has collapsed and sunk. A shallow sea and when the sea water evaporates, therefore, sedimentation is a layer of rock salt inserted throughout the plains.
Later in the Era of Sinozoic The compression of the Earth’s crust creates a fault in the western and southern regions of the Phetchabun, Dong Phaya Yen, Sankampang and Phanom Dong Rak mountain ranges. At the same time, in the middle of the plains, there is a ridge curve from north to southeast It is the Phu Phan mountain range, dividing the low-lying basins in the middle of the region into 2 parts, the one in the north is called “Sakon Nakhon Basin” and the one in the south is called “Korat Basin”.
1. Korat Basin
Flat land area is a large basin. It covers three quarters of the entire Isan region. It is considered the widest plains of Thailand with an average height of 120-170 meters above sea level. The middle area of the basin is a low-lying plain with the Mun River. The Chi River is the main river that drains the water from the plain edge of the basin. Korat basin plains cover the western area. From Nakhon Ratchasima, Chaiyaphum, Khon Kaen, Buriram, Surin, Si Saket, Mahasarakham, Roi Et, Kalasin, Yasothon, Amnatcharoen to Ubon Ratchathani Province in the east. It is surrounded by mountains of Phetchabun, Dong Phaya Yen, San Kamphaeng, Phanom Dong Rak and Phu Phan mountains.
2.Sakon Nakhon Basin
The area is a plain basin in the north of the region. It is much smaller than the Korat basin. The average height is 140-180 meters above sea level. The most important river is Songkram River. Sakon Nakhon basin covers an area in Udon Thani Province, Nong Khai, Sakon Nakhon, Nakhon Phanom Province. The main topography of the Sakon Nakhon basin is that it has large fresh water lakes such as Nong Han Luang, Sakon Nakhon and Nong Han, Kumphawapi, Udon Thani, etc.
Topography of the Sakon Nakhon Basin and the Korat Basin
- The terrain has high humps and basins. Topography generally has low hills which in the dialect is called a Khok or Phon, alternating with a lowland basin, which may have waterlogged in a marsh of different sizes The breakdown of rocks due to the weather, caused by the dissolution of underground rock salt by the action of groundwater, causing the ground to collapse into an underground basin of the Isan region, there are 3 layers of rock salt from the shallow level of 30-40 meters to a depth of 800 meters and up, there is a dense layer of salt rock, causing the surface mound from the terrain that is the hump and the basin causing two important effects on the Isan region. There are many natural water sources widely spread, but at the same time, the abundance of salt rock creates a problem of salinity, which is harmful to agriculture and impedes the use of both soils and groundwater.
- Basin-type terrain is a type of topography which arises from the action of lateral water erosion and vertical deposition causes the plains in the two basins to be very smooth, with almost no slope, so there is always flooding in this area. The river basin area in the Korat basin consists of the Chi River basin. In Khon Kaen, Maha Sarakham, Roi Et and Yasothon provinces with the Mun River basin In Nakhon Ratchasima, Buriram, Surin, Srisaket and Ubon Ratchathani provinces Lowland Flood and courtyard form the Mun-Chi River basin is a large plain. A pan basin is spacious. The nature of the river flows back and forth with curves and the terrain is a shortened river path, forming a small lake scattered in the lowlands. And in the rainy season, there will be floods throughout the plains For the watershed in Sakon Nakhon Basin, it is a small river basin scattered in various rivers such as Songkhram River Plain which is the most plain in the Sakon Nakhon basin, etc. This Sakon Nakhon basin has a special topography, ie, a floodplain, which has waterways connecting with many small lakes that are scattered around the Sakon Nakhon basin. During the dry season and will become a large lake. During the rainy season it becomes an extremely important fishing area in the Northeast.
Different types of minerals found in the Northeast region.
- Antimony is the only source of this mineral at Ban Sa-ad, Nam Salai Subdistrict, Muang District, Loei Province. The advantage of antimony is that it is used in the making of lead alloys, to make lead-and-tin battery plates, to make lead, typefaces and some types of solder. Used in projectile components and match industry, rubber-making, cloth-making, fire-resistant fabrics and ceramics industries
- Barite from the survey of the Department of Mineral Resources showed that Barite sources were found in 2 local provinces: Loei and Udon Thani. In the province of Loei found at Ban Hin Khao. Chiang Khan Districts, Ban Na Kho, Pak Chom District, Ban Huai Pod, and Ban Tha Pha In Udon Thani Found at Ban Nadi, Naklang District But there are no details about the mineral content that has been found to benefit rebarrite. Most of them are used to make drilling mud, which is used in drilling exploration of oil or well water used in the paint and texture industry Glass and rubber, oilcloth, paper, oil and plastic industries Used to make oral medicine before X-ray examination of the stomach and intestines. Used as a filler in various industries, used in the tanning industry, making flour, face puff, etc.
- Copper ore, there are many copper ore sources in this region, namely the “Khao Phat Mae Nam”, Phu Wiang District, Khon Kaen Province, Chanthuek Field, Pak Chong District, Nakhon Ratchasima Province, Phu Hin Lek Lai and Phu Ang. It is located in the south of Phu Hin Lek Fai as well. In addition to the three large areas above, Department of Mineral Resources used to survey copper ore sources in Sangkhom district, Nong Khai Province as well. The benefits of copper ore The copper metal is smelted for use in various industries such as in the making of electrical equipment, electrical wires, equipment, radio, television, telegraph, telephones, mechanical machines, engines, as well as scientific instruments. And various weapons and equipment and used to make many alloys Such as gold, bronze, brass, etc.
- Most of the gemstones found in the family of corundum or emery, found at Kantharak district in blue sapphire and green sapphire. In addition to the gems found, there are also minerals that occur together, such as garnet, niltako, and zircon. Ubon Ratchathani Province Found in the area of Huai Ta Yoke, Ban Dan, Ban Don Yang, Ban Khok Saen, Ban Tak Kao, Ban Tak Kao, Ban Don Mok and Ban Nong Kum The area is adjacent to the Kantharak district. Most of the gemstones mined were zircon. There were also reports of precious stones found at Phu Pha, Lamduan Det Udom District Ubon Ratchathani province as well. The benefits of gemstones In addition to being used as a valuable accessory. For example, sapphire is used in the small watchmaking industry, and it is also used as a residue for sharpening very solid blades and making sandpaper, powdered zircon abrasive cloth, used in crockery, sand making, refractory bricks, for aluminum smelting furnaces, and for metal glass used in atomic machines and in many alloys.
- Gypsum found at Ban Non Chaeng. Kham Sakae Saeng District Nakhon Ratchasima and Wang Saphung District, Loei Province. Gypsum minerals, also known as dark salt, are usually white, gray, yellow, red and brown. Due to the impurity, it may have a crystal shape, a burr or a grain like sand, soft mineral content is easily scratched. The nature of the mineral resources is often layered. The benefits of gypsum are used in making cement, plaster, plaster, gypsum board, making powder, chalk, fertilizer, paper, crayon and rubber.
- Lead and zinc ores in the Isan region are found in the Phu Khum area. Chiang Khan District, Loei Province. Benefits of lead – zinc can be used as a mix of many types of metals, paper, lead, food wrapping, cigarettes, water pipes, lead sheets, cartridge typography, electric fuses, atomic radiation barrier and paint. The zinc It is mainly used in the coating of steel plates, made of galvanized thatch roof The cans lined in the shell of the batteries. And can be used for casting various parts of automobile parts such as carburetors, etc. It is also used in drug making and chemical use.
- Lignite coal discovered in Sahatsakhan district and Kuchinarai Kalasin Province, Khamchaee District, Nakhon Phanom Province, at Khao Lak Antel, Khraburi District, Nakhon Ratchasima Province and Sawang Daen Din District, Sakon Nakhon Province. The most important benefit of coal is that it is used as a fuel for burning. Instead of wood charcoal and oil, it is used instead of pressed charcoal to be used as a fuel for cooking and various industries making gas in cooking. It is also used to make chemical fertilizers, ammonium sulfate type and urea.
- Manganese found in Huai Phang, Huai Kok Ha, Huai Muang, Huai Suok and Pak Chom, Chiang Khan District, Loei Province, is a type of manganese used to make batteries. Therefore started the mining of manganese ore as the first source of the country to produce minerals for using in the battery industry.
- Phosphate mineral found at Tambon Nong Ngio, Wang Saphung District, Loei Province. The benefits of most of phosphate, about 70 percent, are used in making fertilizers. In addition, it is used for other purposes, such as for cooking animal food, detergents, electrical materials, abrasive devices, pesticides, toothpaste, medicine, matches, pesticides, toothpaste and explosives.
- Emery and Silimanite were first discovered in Thailand at Ban Non Sao Ae and Ban Bub E-Poon, Takop Sub-district, Pak Thong Chai District, Nakhon Ratchasima Province. The major benefit of Emory is its use in the scrubber industry such as the mill Rice mill, grinding stone, sharpening stone, knife, terrazzo, concrete floor polishing stone, sandpaper is mixed with chemical liquid to be used as a polishing agent. In addition, the melted emery is used to polish glass to frosted glass and the fine powder and high purity types are used for polishing. Can also scrub the lens It is widely used in concrete to make floors of porches, stairs and slopes to prevent slippage. Sillimanite benefits are used in industrial refractory bricks with high heat resistance and due to its heat resistance properties, up to 1810 degrees celsius, so it is useful in making other tools that are resistant to high heat, such as making special pottery, chemical and electrical equipment.
- Uranium in sandstone was discovered as the first source in the Jurassic sandstone strata. The mineral source is located in the Phu Wiang basin near the west side with the northwest edge of the Korat plain in Ban Nong Kham district, Khao Noi sub-district, Phu Wiang district, Khon Kaen province
- Petroleum, Department of Mineral Resources has cooperated with petroleum experts many times, it was found that some Northeastern region used to be the source of petroleum organic matter, together with the sample analysis, confirm that the amount of such organic substance It has the ability to refine to produce oil and natural gas. The upper rock layer covering the petroleum origin rock is made up of very porous sandstone covered with shale. The Jurassic period, which can be a reservoir and a petroleum-blocking rock, respectively. Some of the Permian and Thyristian shale layers also contain sandstone and shale, which contain and block petroleum. In addition, the thickness of the rock from the origin rock to the surface is as thick as 5000 meters, indicating a long accumulation of deposits, causing natural heat and pressure combined with the internal heat of the earth. Combined with bacteria and chemical catalysts, organic matter is converted into oil or natural gas and transferred to storage in the porous shale in a suitable structure according to the Earth’s surface transformation force.
- Gold found by accumulating in the soil by the flow of water, similar to the formation of an ore. The surveyed sources were found in Phu Tham Phra, Muang District, Loei Province and at Ban Kham Duang District, Ban Phaeng District, Udon Thani Province. It is a gold ore that occurs in conjunction with platinum, but the exact quantity is not known. The usefulness of gold is used as a collateral for the value of banknotes, mint, making jewelry, mixing other metals, as well as alloys, used in dentistry, scientific instruments and electrical circuits etc.
- Iron ore sources in Loei Province, for example at Phu Ang, Phu Khok, Phu Khunthong and Phu Hin Lek Fai. Iron ore sources in Chiang Khan district at Phu Yang, Phu Sang, Phu Hia, Phu Kaew Yai and Phu Iron Ban that are also available in Wang Saphung District at Bo E-lud and Pa Pao.
- Rock-salt source found in the Isan region, is mostly the result of drilling wells in the Korat rocks, covering an area in the Sakon Nakhon basin, approximately 19,500 square kilometers and in the Korat basin 37,300 square kilometers. The amount of rock salt reserves obtained from drilling in various experimental in this region, it is estimated that there are about 4,700 million tons, and it is expected that the amount of rock salt in this region will be enormous, up to 2 trillion tons, which will be obtained from 7 major sources, namely Chaiyaphum source, Kaew market, Mahasarakham source. Bamnet Narong source, Ubon source, Kula weeping source Udon – Nong Khai source. The advantage of rock salt in industrial applications is that it is used as an essential raw material in the production of chemicals and acids used in handicrafts, used as a separating component Smelting and smelting ore in metalworking business, used in various chemical industries such as soap making, dyeing, tanning, medicine, toothpaste, cement, explosion, enamel, bleaching cloth and paper, pottery industry, glass industry and refrigeration industry. It is also used as food, fertilizers, pesticides, medicine and dentistry.
- Potash salt exploration in this region was started in 1974, and potash was found in Muang district, Udon Thani Province. From the survey of the Department of Mineral Resources found that this region has many layers of rock salt and potash. This will generate more income for this area than any other mineral, so the government policy is to support the exploration of rock salt and potash in the northeast first. The results of the ongoing drilling of potash and rock salt from 131 wells, totaling 130378 feet in depth in both the Korat and Sakon Nakhon basin. The two most common potash minerals are Carnallite while silwhite is found in patches. The important benefit of potash is fertilizers, various chemical industries, pottery industry, glassware, dyeing, tanning, soap making, plywood, photography equipment.
Mekong, Chi, Mun and Songkram Rivers
The river is the path of life and the birthplace of the Isan civilization. There are major rivers and rivers which are the source of life and the birthplace of culture that has been a long time in this region with major rivers, Songkram River, Chi River, Mun River and Mekong River.
The hydrological characteristics of the Isan region are related to the Mekong River because the drainage system from the area is a creek and a river in relation to the Mekong tributaries. From the inner river groups flowing into the Mekong River. It is the most important tributary of the Mun River and the Chi River as its affiliate tributary. In the upper part, there is an important branch of Songkhram River. There are 3 upstream areas of the Isan region, which are
- Watershed of the Western Mountains are the main source of the Mun and Chi rivers.
- Watershed of the southern mountains are the origin of the sub-tributaries of the Mun River
- Phu Phan mountain range is the watershed of both the upper Sakon Nakhon basin and the lower Korat basin, which the river in the Korat basin flows into the Chi river The upper part of the Sakon Nakhon basin flows directly into the Songkram river and the Mekong river.
Rivers in Isan
- The Mekong River is an international river with a length of 4,590 km. It is the 10th longest river in the world and the sixth largest volume of fresh water in the world, flowing through various countries’ territories. It has natural border between China, Myanmar, Thailand, Laos, Cambodia and Vietnam. The Mekong River is divided into two parts: the upper Mekong River in China, Myanmar and Laos, and the lower Mekong River in Laos, Cambodia and Vietnam. Geography, society and economy, The Mekong River is also important to the spiritual value of the community along both sides of the Mekong. It is the birthplace of many races of civilization in this river basin, ideas, philosophies, worldviews, beliefs, as well as unmatched culture and traditions reflected in the form of respect for the river, such as the belief in Naga And the ritual of catching catfish Similarly, from Xishuangbanna, Burma, Lanna to Thailand, Laos, Cambodia and Vietnam, the Upper Mekong River. Originates in the mountains in the Tibetan Plateau. Thangla mountain range on the top of Tungla Mountain at an altitude of more than 16,700 feet above sea level, called in the local language as Dzesu, the Mekong River is characterized by a narrow and shallow flow through the gorges and steep rocky gorges only 100 meters wide, it flows down parallel to the Salween and Yangtze rivers to Sichuan Province And the Sipsongpanna region. It then began to slowly expand and called the Lan Chang River or Gao Lung River. During this period, the river is gradually descending every 400 feet per 1 degree, which is characterized by the effect of the Mekong River but there is still a strong current and narrow water, so it is not used for much transportation. Then flows into the south It is the border between Burma and the donkey. And came down to the Golden Triangle (Sop Ruak) at Chiang Saen District Chiang Rai Province and enter the lower Mekong. The lower Mekong River is gradually widening as there are numerous tributaries in both Thailand and Laos flowing into the Mekong River in this area, thus having the width and currents suitable for transport, but there are major obstacles that are the islands that In the middle of many rivers It will then flow into Laos at Chiang Khong District. Chiang Rai and Wok provinces back into the Thai-Laos border again at Chiang Khan District, Loei Province, passing Nong Khai, Nakhon Phanom, Mukdahan, Amnat Charoen District to Khong Chiam District, Ubon Ratchathani Province which is more than 850 kilometers, and the distance that forms the Thai-Laos border is approximately 95 kilometers, the Mekong River is very extensive, in the range of about 800-1200 meters, the widest in Amnat Charoen Province and in the area of Mukdahan Province approximately 2,300-26,000 meters and the flow is rather lazily. During the dry season there is less water, dries up until it forms uplands or sandy beaches in the middle of the river and some places can be crossed over, plentiful from the sedimentation of the river And the produce from these Don areas is more expensive than others, then the Mekong River flows into the South China Sea at the tip of the Vietnamese Cape, about 85 kilometers from Ho Chi Minh City.
- The Mun River is the most important tributary of the Mekong River. It originated between Khao Wong and Khao Lamang in the San Kamphaeng mountain range, in Nakhon Ratchasima Province. It is the longest river in this region is 641 kilometers long, with a basin area of approximately 70,100 square kilometers, parallel to the Khao Phanom Dong Rak. The slope of the river is reduced by an average of 52 meters or 16 centimeters per kilometer, causing the floodplains in the Mun River to be flooded annually because the water cannot be drained in accordance with the water capacity In addition, the area where the basin still has a rocky layer of laterite soil which makes the water unable to flow as well. Major branches of Mun River are Lam Takhong, Lam Chakraj, Lam Sae, Lam Phra Ploeng in Nakhon Ratchasima Province. Lam Plai Mat in Buriram Province Lam Chi and Lam Si River in Surin Province, Huai Thap Than, Huai Samran Province, Sisaket Province, Lam Se Bok, Lam Se Bai, Lam Dome Yai and Lam Dome Noi in Ubon Ratchathani Province Including the river that flows into Mun River in Yasothon Province. The Mun River flows into the Mekong River in Khong Chiam district Ubon Ratchathani Province
- The Chi River is the second longest river in the region with an area of approximately 55,100 sq km which is a relatively dry area. The amount of water in the Chi River is therefore not large. It receives most of its water from the major branches in the north, namely Nam Phong and Pao River. Nam Phong is the most important branch of the Chi River, 275 kilometers in length and high economic importance. Especially after the construction of the Ubolratana dam, The Pao River, the second most important tributary of the Chi River, has a length of 236 kilometers.t
- Songkhram River is the most important river of the upper Isan region, it has its headwaters in the Phu Phan mountain range, with an area of 20,411 square kilometers, 420 kilometers long along both sides of the river. Especially in the Sakon Nakhon and Nakhon Phanom districts, it is characterized by grasslands and floodplains as soon as the rain rains and the water level rises, forming many small lakes that are fishing grounds. The major tributaries are the Oon River, which originates in the Phu Phan mountain range. The length is about 270 kilometers.
Other water sources in Isan
Surface water source
The surface water of the Isan region are quite abundant due to the terrain of the hump, interspersed with basins, and the rainfall is moderate to very high. Therefore, surface water bodies appear everywhere in the Isan region, but the amount of water runoff and flood rapidly. Especially in lowland plains as well as poor soil quality. Has a high rate of water loss. The surface water in the Northeast is often dry during the dry season. In addition, the forest, which is the source of the water stream, has been greatly destroyed. As a result, the Isan region has to face more drought problems than other regions of the country.
Underground water source
There are very important nowadays because it is a way to solve the problem of water shortages in the dry season of the Northeast. There are two levels of groundwater survey:
- Groundwater is a layer that receives water from infiltration at the beginning of the rainy season can be excavated by digging by the villagers. This groundwater is highly sensitive to drought. When the rain stops, the water will slowly dry out as well.
- Deep groundwater has little change in water level, even in the dry season. However, this type of groundwater must be digged very deep and requires expertise and high technology. This requires a detailed survey of the amount of water and the salt layer under the land, because pumping may cause the soil to subside and dissolve the rock salt layer causing poor water quality to become salt water And may cause the soil to have higher salinity than before.
There are many types of forests in the Isan region. There are different types of wood. It has the characteristics of a combination of important characteristics of the soil in this region. It is sandy soil, therefore it lacks fertility and does not retain water. It has a high rate of soil erosion, The destroyed forest could not be restored to its original state in time and turned into a degraded forest scattered throughout the region. This has greatly affected the problem of flooding and hydrology.
Types of forests in Isan
- Dry Dipterocrap Forest is the most common forest in the Isan area, which is more than 50 percent of the forests in this region. Pa Daeng may be called Pa Khok, Pa Khae which can grow well in this area because the soil is well drained and the decay of laterite is high with low soil moisture. The forest looks clear with sunlight coming down to the ground Below and there are grass, bamboo, thick shrubs. The most common plants are red rubber, antimony, hiang rang, maca, tengfa, tengtani, etc. This forest is economic importance for the villagers.
- Mixed Deciduoust Forest found in the mountains of the region, closely related to the dry evergreen forest which are always found together. Mixed deciduous forest is a deciduous forest divided into moist mixed forest and dry mixed forest, classified by annual rainfall between 1,270-2,030 mm per year, it is a humid mixed forest. If it is lower than 1,270 mm per year, it is a dry mixed forest. The plants found have taller trunks than Daeng Forest, such as Si Saiad Takhian, Ratchaphruek, Rukfah, Pradau, Elephant sugar cane, Ebony rubber, Sian Tabaek, Big Tabaek, etc. It has high economic value and daily life of the villagers as well.
- Savanna Forest is a degraded forest caused by deforestation and it is more and more present due to shifting cultivation. This type of forest has grasslands and low trees scattered across the soil, not fertile and with gravel sand. Thung Kula Rong Hai is the forest fields that have become worn out and turned into grasslands.
- Tropical Evergreen Forest exists in the western, central and southern part of the Phu Phan mountain range. It consists mostly of medium sized trees. There are bamboo inserts everywhere. Important plants such as Yang Takian – Thong Sayamakhaong, Payungtabaek, etc. may be found mixed with dry evergreen forests and there are deciduous fruit trees which is a rainforest feature that is different from the rainforest in other regions.
- Dry Evergreen Forest is a humid monsoon forest found in Nakhon Phanom and Phu Phan mountain range There are not many, may be found in low valleys. To an area of about 1,000 meters high near the stream, which is green all year round Even though there may be only 1,500-2,000 mm of rainfall per year, the more dense plants such as the rubber tree, Takhian, Hin Takhian, Lam Wa Khoi Sai, Olive, Ngiu, Taew, Kabaow, and many more ivy and vines at the lower levels.
- Hill Forest, Lower montane Forest found on mountains 1,000 meters up high, plant family plants, such as white-made spurs, Phaya wood, Champi, blood-forming forests, siam-wah, frankincense, etc., with pine trees mixed with ferns, mosses, and smaller plants. It is found mostly in the western mountains.
- Coniferous Forest in Thailand, there are two types of pine, two-leaf pine and three-leaf pine, oil pine, found in relatively arid regions and high mountain ranges from 700-1,000 meters and above, it will be mixed with Daeng Forest or some other forest, but generally found that standalone and there are no other cultivars. It has economic value in terms of making turpentine and pine.