Tarim Basin
The Tarim Basin is an endorheic basin in Xinjiang, Northwestern China occupying an area of about and one of the largest basins in Northwest China. Located in China's Xinjiang region, it is sometimes used synonymously to refer to the southern half of the province, that is, Southern Xinjiang or Nanjiang, as opposed to the northern half of the province known as Dzungaria or Beijiang. Its northern boundary is the Tian Shan mountain range and its southern boundary is the Kunlun Mountains on the edge of the Tibetan Plateau. The Taklamakan Desert dominates much of the basin. The historical Uyghur name for the Tarim Basin is Altishahr, which means 'six cities' in Uyghur. The region was also called Little Bukhara or Little Bukharia. The basin is a major area for renewable energy development, particularly solar and wind power, with a focus on utilizing the vast Taklamakan Desert. A high-voltage power loop has been constructed around the basin, collecting energy from various sources and transmitting it to other regions.
Geography and relation to Xinjiang
consists of two main geographically, historically, and ethnically distinct regions with different historical names, Dzungaria and the Tarim Basin, until it was merged into the Chinese Province of Xinjiang in 1884. At the time of the Qing conquest in 1759, Dzungaria was inhabited by steppe-dwelling, nomadic Mongolic Buddhist Dzungars, while the Tarim Basin was inhabited by sedentary, oasis-dwelling, Turkic-speaking Uyghur Muslim peasants. Dzungaria and the Tarim Basin were each governed separately until the creation of Xinjiang province.Tarim Basin locations
North side
The Chinese called this the Tien Shan Nan Lu or Tien Shan South Road, as opposed to the Bei Lu north of the mountains. Along it runs the modern highway and railroad while the middle Tarim River is about 100 km south. The caravans met in Kashgar before crossing the mountains. Bachu or Miralbachi; Uchturpan north of the main road; Aksu on the large Aksu River; Kucha was once an important kingdom; Luntai; Korla, now a large town; Karashar near Bosten Lake; Turpan north of the Turpan Depression and south of the Bogda Shan; Hami; then southeast to Anxi and the Gansu Corridor.Center
Most of the basin is occupied by the Taklamakan Desert which is too dry for permanent habitation. The Yarkand, Kashgar and Aksu Rivers join to form the Tarim River which runs along the north side of the basin. Formerly it continued to Loulan, but some time after 330 AD it turned southeast near Korla toward Charkilik, and Loulan was abandoned. The Tarim ended at the now-dry Lop Nur, which occupied a shifting position east of Loulan. Eastward is the fabled Jade Gate which the Chinese considered the gateway to the Western Regions. Beyond that was Dunhuang with its ancient manuscripts and then Anxi at the west end of the Gansu Corridor.South side
Settlements include Kashgar; Yangi Hissar, famous for its knives; Yarkand, once larger than Kashgar; Karghalik, with a route to India; Karakash; Khotan, the main source of Chinese jade; eastward the land becomes more desolate; Keriya ; Niya ; Qiemo ; Charkilik. The modern road continues east to Tibet. There is currently no road east across the Kumtag Desert to Dunhuang, but caravans somehow made the crossing through the Yangguan pass south of the Jade Gate.Roads and transportation
Railways
The whole Tarim Basin and the Taklamakan Desert are surrounded by railroads. The Southern Xinjiang Railway branches from the Lanxin Railway near Turpan, follows the north side of the basin to Kashgar, and curves southeast to Khotan, while Hotan–Ruoqiang railway loops around the south and west side of the Traim. They are part of the Taklimakan Desert railway loop, joined together with sections of the Golmud–Korla railway, Hotan–Ruoqiang railway, Kashgar–Hotan railway, and Southern Xinjiang railway.Roads
reaches Ürümqi and continues as highway 314 along the north side to Kashgar. Highway 315 follows the south side from Kashgar to Charkilik and continues east to Tibet. There are currently four north–south roads across the desert. 218 runs from Charkilik to Korla along the former course of the Tarim, forming an oval whose other end is Kashgar. The Tarim Desert Highway, a major engineering achievement, crosses the center from Niya to Luntai. The new Highway 217 follows the Khotan River from Khotan to near Aksu. A road follows the Yarkant River from Yarkand to Baqu. East of the Korla-Charkilik road, travel continues to be very difficult.Rivers
Rivers coming south from the Tien Shan join the Tarim, the largest being the Aksu. Rivers flowing north from the Kunlun are usually named for the town or oasis they pass through. Most dry up in the desert; only the Hotan River reaches the Tarim in good years. An exception is the Qiemo River which flows northeast into Lop Nur. Ruins in the desert imply that these rivers were once larger.Caravans and passes
The original caravan route seems to have followed the south side. At the time of the Han dynasty conquest, it shifted to the center. When the Tarim changed course about 330 AD it shifted north to Hami. A minor route went north of the Tian Shan. When there was war on the Gansu Corridor trade entered the basin near Charkilik from the Qaidam Basin. The original route to India seems to have started near Yarkand and Kargilik, but it is now replaced by the Karakoram Highway south from Kashgar. To the west of Kashgar via the Irkeshtam border crossing is the Alay Valley, which was once the route to Persia. Northeast of Kashgar the Torugart pass leads to the Ferghana Valley. Near Uchturpan the Bedel Pass leads to Lake Issyk-Kul and the steppes. Somewhere near Aksu the difficult Muzart Pass led north to the Ili River basin. Near Korla was the Iron Gate Pass and now the highway and railway north to Ürümqi. From Turfan the easy Dabancheng pass leads to Ürümqi. The route from Charkilik to the Qaidam Basin was of some importance when Tibet was an empire.North of the mountains is Dzungaria with its central Gurbantünggüt Desert, Ürümqi, and the Karamay oil fields. The Kulja territory is the upper basin of the Ili River and opens out onto the Kazakh Steppe with several roads east. The Dzungarian Gate was once a migration route and is now a road and rail crossing. Tacheng or Tarbaghatay is a crossroads and former trading post.
Geology
The Tarim Basin is the result of an amalgamation between an ancient microcontinent and the growing Eurasian continent during the Carboniferous to Permian periods, a process which ended in the earliest Triassic with the closure of the Palaeo-Asian Ocean. At present, deformation around the margins of the basin is resulting in the microcontinental crust being pushed under Tian Shan to the north, and Kunlun Shan to the south.A thick succession of Paleozoic, Mesozoic and Cenozoic sedimentary rocks occupy the central parts of the basin, locally exceeding thicknesses of. The source rocks of oil and gas tend to be mostly Permian mudstones and, less often, Ordovician strata which experienced an intense and widespread early Hercynian karstification. The effect of this event are e.g. paleokarst reservoirs in the Tahe oil field. Below the level enriched with gas and oil is a complex Precambrian basement believed to be made up of the remnants of the original Tarim microplate, which accrued to the growing Eurasian continent in Carboniferous time.
The snow on the Karakoram mountain range flows into glaciers which move down the valleys to melt. The melted water forms rivers which flow down the mountains and into the Tarim Basin, never reaching the sea. Surrounded by desert, some rivers feed the oases where the water is used for irrigation while others flow to salt lakes and marshes.
Image:Tarimrivermap.png|thumb|The Tarim Basin, 2008
Lop Nur is a marshy, saline depression at the east end of the Tarim Basin. The Tarim River ends in Lop Nur.
The Tarim Basin is believed to contain large reserves of petroleum and natural gas. Methane comprises over 70 percent of the natural gas reserve, with variable contents of ethane and propane. China National Petroleum Corporation's comprehensive exploration of the Tarim basin between 1989 and 1995 led to the identification of 26 oil- and gas-bearing structures. These occur at greater depths and in scattered deposits. Beijing aims to develop Xinjiang into China's new energy base for the long run, supplying one-fifth of the country's total oil supply by 2010, with an annual output of 35 million tonnes. On June 10, 2010, Baker Hughes announced an agreement to work with PetroChina Tarim Oilfield Co. to supply oilfield services, including both directional and vertical drilling systems, formation evaluation services, completion systems and artificial lift technology for wells drilled into foothills formations greater than deep with pressures greater than and bottom-hole temperatures of approximately. Electrical submersible pumping systems will be employed to dewater gas and condensate wells. PetroChina will fund any joint development.
In 2015, Chinese researchers published the finding of a vast, carbon-rich underground sea beneath the basin.
History
It is speculated that the Tarim Basin may be one of the last places in Asia to have become inhabited: It is surrounded by mountains and irrigation technologies might have been necessary.The Northern Silk Road on one route bypassed the Tarim Basin north of the Tian Shan mountains and traversed it on three oases-dependent routes: one north of the Taklamakan Desert, one south, and a middle one connecting both through the Lop Nur region.
- The northern Tarim route ran from Kashgar via Aksu, Kucha, Korla, through the Iron Gate Pass, then Karasahr, Jiaohe, Turpan, Gaochang and Kumul to Anxi.
- The southern Tarim route ran from Kashgar through Yarkant, Karghalik, Pishan, Khotan, Keriya, Niya, Qarqan, Qarkilik, Miran and Dunhuang to Anxi.
- The middle Tarim route, the shortest of the four, connected Korla on the northern Tarim route through Loulan and across the Lop Nur region and Dunhuang on the southern Tarim route. The Lop Nur region became uninhabitable in the 4th century and the middle route has been deserted since the 6th century.