Chott el Djerid
| Chott el Djerid | ||
|---|---|---|
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| The Chott el Djerid on the causeway from Tozeur to Kebili | ||
| Geographical location | in the south of Tunisia | |
| Tributaries | Watercourses from the northern mountains | |
| Drain | no | |
| Places on the shore | Tozeur , Nefta | |
| Data | ||
| Coordinates | 33 ° 43 ' N , 8 ° 22' E | |
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| Altitude above sea level | 15 m | |
| surface | 5 360 km² | |
| length | 250 km | |
| Catchment area | 10,500 km² | |
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particularities |
largest salt lake area in the Sahara |
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The Chott el Djerid ( Arabic شط الجريد, DMG Šaṭṭ al-Ǧarīd , also Schott el Dscherid ) is a sedimentary basin within a depression with a salt lake in southern Tunisia . The lake itself is usually referred to alone as Chott el Djerid . In ancient times, the area was Tritonis ( Tritonis Lacus or Tritonis Palus ) after the river Triton , the lake or marsh fed, and later Salinarum Lacus called ( "salt lake"). However, the geographical allocation is not entirely certain.
geography
Together with its continuations Chott el Fedjadj (lying to the east) and Chott el Gharsa (lying to the west) the depression has an area of 7,700 km² and a west-east extension of approx. 200 km from the Algerian border to almost the Mediterranean . The greatest width of the region is around 70 kilometers. This makes it the largest salt lake area in the Sahara .
The Chott el Djerid forms a basin without drainage, which received its present form in the late Tertiary . In the contact zone between the rigid Sahara plateau and the North African Atlas region , flexures , anticlines , faults and slight terrain waves were created by tectonic processes . Erosion and further elevations in the terrain created a ridge-stratified landscape in southern Tunisia that surrounds the Chott el Djerid. The crescent-shaped Djebel Tebaga forms its southern border .
The surfaces of the Chott el Djerid are around 15 m above sea level and those of the eastern Chott el Fedjadj rise to 25 m. The western Chott el Gharsa is already below sea level. The depression, which extends into Algeria, deepens in a westerly direction and sinks in the local Chott Melghir to −26 m. However, the area is still in the phase of tectonic uplift, and an uplift rate of 1 to 3 mm per year can be assumed.
The salt lake is fed by watercourses from the northern mountains that carry washed-out salts with them. Due to the extreme climatic conditions (annual precipitation 100 mm, maximum temperatures up to 50 ° C) the water evaporates and the salts crystallize to a dry crust, under which there is deep silt. In the summer the chott dries out almost completely and becomes a salt flat . It is largely a fine-laminar layer of plaster with clay mineral deposits .
Here sand roses are extracted from depths of up to 50 m. Specimens with a weight of up to 6 t are found.
After rains in winter and spring, large parts of the chott are flooded or silted up. Especially in summer, mirages ( mirages ) occur when the sun is high .
The salt lake got its name from the northern oasis region Bled el Djerid (Arabic:بلاد الجريد"Land of the Date Palms"). The main towns of this region are the oasis towns and former caravan stations Tozeur and Nefta . South of the Chott el Djerid begins the full desert with the eastern foothills of the Eastern Great Erg . To the southeast of the salt lake is the oasis area Nefzaoua with the main towns Kebili and Douz . During the French colonial era , a dam-like slope was built up that connects Tozeur with Kebili. In the meantime, this had become impassable, but in 1979 an asphalted dam road that was passable all year round was created. Next to the road you can still see the palm fronds , originally inserted into the salt crust, which hikers, camel drivers and, since the 20th century, motorists used to orient themselves.
At the end of the 19th century there were plans to connect the Chott el Djerid with the sea by a canal and thus create a huge lake. However, the plan failed because the surface of the Chott turned out to be slightly above sea level.
Before the dam road was built, crossing the Chott el Djerid was often dangerous due to the treacherous salt crust, even if it is firm enough in places to allow trucks to drive on it.
From the 14th century, the disappearance of a caravan with 1000 camels and their drivers without a trace is recorded.
Reception in literature and film
In the first volume of his adventure novel Through the Desert and Harem (later Through the Desert ) of the Orient cycle Im Schatten des Padishah , Karl May describes the dangers of crossing the Chott el Djerid.
The Chott el Djerid was used, among other things, as a location for all three Star Wars trilogies (episodes 1-9).
literature
- Horst Mensching : Tunisia (= Scientific Country Customers. Volume 1). Scientific Book Society, Darmstadt 1974.
- Peter H. Kemp: Chemism of Tunisian Waters & Land Classification of the Oglat Merteba Steppe Test Zone in S-Tunisia (= Berlin Geoscientific Treatises. Series A / Volume 58). Reimer, Berlin 1985, ISBN 3-496-00244-1 .
- Peter H. Kemp: Model experiment: Calcium carbonate & gypsum new formations in capillary-porous media under simulated Sebkha-like conditions in the climatic chamber (= Berlin Geoscientific Treatises. Series A / Volume 80). Reimer, Berlin 1986, ISBN 3-496-00337-5 .
Web links
Individual evidence
- ^ A b Robert G. Bryant: Application of AVHRR to monitoring a climatically sensitive playa. Case study: Chott el Djerid, southern Tunisia . In: Earth Surface Processes and Landforms . tape 24 , 1999, pp. 382–302 ( citeseerx.ist.psu.edu [PDF; accessed September 17, 2013]).
- ↑ Werner Huss : Triton (2). In: The New Pauly (DNP). Volume 12, Metzler, Stuttgart 2002, ISBN 3-476-01470-3 , Sp. 834.
- ↑ geo.fu-berlin.de
- ↑ mineralienatlas.de