Makgadikgada Lake
| Makgadikgada Lake | ||
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| The assumed maximum extent of the Paleo Deceptionsee in the early Pleistocene and the course of the rivers in the early to middle Cenozoic . | ||
| Geographical location |
 Botswana
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| Tributaries | Paleo- Zambezi , - Okavango , - Kafue , - Chambeshi | |
| Data | ||
| Coordinates | 20 ° 12 ′ S , 24 ° 16 ′ E | |
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| Altitude above sea level | 1000 m | |
| surface | 175,000 km² | |
| Maximum depth | 85 m | |
| Middle deep | 30 m | |
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particularities |
Former lake |
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| Part of the region of the former Lake Makgadikgadisee on a SPOT satellite image | ||
The Makgadikgadisee is a former lake (paleo lake) that existed in what is now Botswana north of the Kalahari and that dried up in the Holocene . In its place are the Makgadikgadi Salt Pans and the Okavango Delta today .
description
Strictly speaking, the Makgadikgadisee is the southern basin of a lake that was once more than twice as large, the Deceptionsee. Its highest shoreline is 990 to 1000 m and covers an area of 175,000 km². A total of 5 different shorelines have been found so far.
The actual Makgadikgadisee lies at 945 m and below with an extension of about 60,000 km², so only slightly smaller than the area of today's largest lake in Africa, Lake Victoria . However, it is also used synonymously for all bank lines with the associated altitude.
development
The Makgadikgadisee was formed in the Pleistocene , when tectonic processes cut the course of the Cuando , the upper Zambezi and the Kafue from the lower and middle Zambezi , and directed them into a basin without drainage . Climatic changes caused great changes in the water level and the extent of the Makgadikgadi lake. At the height of the Last Ice Age 18,000 years ago, when the lake levels of Lake Tanganyika and Lake Malawi were 500 to 600 meters lower, it may have dried up.
But also erosion and tectonics had a strong influence. First of all , the Chambeshi fell away, which until then had extended the Kafue, since then it has belonged to the Congo catchment area. Then the Kafue shifted its course over the Kafue floodplains to its current bed. And finally, in the course of the Holocene, an outflow formed in the northeast of the lake when the Zambezi broke through the Mambova fault above the Victoria Falls, so that it no longer flowed into the Makgadikgadi Basin. As the last, the course of the Cuando was diverted by a sand dune to the Zambezi, although it is still partly in contact with the Okavango.
Since about 2000 BC only Makgadikgadi Pans remain Lake Ngami , Mababe depression , Liambesisee and the Okavango Delta left as relics of the lake.
fauna
Despite its relatively short existence, Lake Makgadikgadisee was an important center of adaptive radiation of haplochromin cichlids . A subgroup of these cichlids, informally referred to as "Serranochromini", occurs with 43% of their species in the Okawango , middle and upper Zambezi. Another 28% live in the upper Congo , 20% in the upper Kasai , while there are no Serranochromini in the lower Congo. Similar distributions are found in carp fish of the genera Enteromius , Labeobarbus and Labeo , in African tetras (Alestidae) and catfish of the genus Chiloglanis . The distribution of the species suggests a species emergence in Lake Makgadikgadisee.
supporting documents
- ↑ a b c The evolution and ages of Makgadikgadi paleo-lakes: consilient evidence from Kalahari drainage evolution south-central Africa
- ^ The Zambezi River - Andy E. Moore, Fenton PD (Woody) Cotterill, Mike PL Main and Hugh B. Williams
- ↑ Joyce, DA, Lunt, DH, Bills, R., Turner, GF, Katongo, C., Duftner, N., Sturmbauer, C. & O. Seehausen (2005): An extant cichlid fish radiation emerged in an extinct Pleistocene lake. Nature . 2005 May, 435: 90-95.
Web links
- National Geographic News, James Owen: Lost African Lake Spawned Fish Diversity "Beyond Belief".