Karoo - WikiHQ

The Karoo ( ; likely from Khoikhoi (also known as Khoekhoegowab/Namagowab or Hottentot language) word ) is a semidesert natural region of South Africa. No exact definition of what constitutes the Karoo is available, so its extent is also not precisely defined. The Karoo is partly defined by its topography, geology and climate, and above all, its low rainfall, arid air, cloudless skies, and extremes of heat and cold. The Karoo is also known for its exposure of the fossiliferous rocks of the Karoo Supergroup, which records in detail ecological change in the region when it formed part of southern Pangaea from the Middle Permian to the Early Jurassic, around 270 to 200 million years ago.

The Karoo formed an almost impenetrable barrier to the interior from Cape Town, and the early adventurers, explorers, hunters, and travelers on the way to the Highveld unanimously denounced it as a frightening place of great heat, great frosts, great floods, and great droughts. Today, it is still a place of great heat and frosts, and an annual rainfall of between , though on some of the mountains it can be higher than on the plains. and becoming very sparse going northwards into Bushmanland and, from there, into the Kalahari Desert. The driest region of the Karoo, however, is its southwestern corner, between the Great Escarpment and the Cederberg-Skurweberg mountain ranges, called the Tankwa Karoo, which receives only of rain annually.

Today, sheep thrive on the xerophytes, though each sheep requires about of grazing to sustain itself.]]

The only sharp and definite boundary of the Great Karoo is formed by the most inland ranges of Cape Fold Mountains to the south and south-west. The extent of the Karoo to the north is vague, fading gradually and almost imperceptibly into the increasingly arid Bushmanland towards the north-west. To the north and north-east, it fades into the savannah and grasslands of Griqualand West and the Highveld. The boundary to the east grades into the grasslands of the Eastern Midlands.

The Great Karoo is itself divided by the Great Escarpment into the Upper Karoo (generally above ) and the Lower Karoo on the plains below at .

A great many local names, each denoting different subregions of the Great Karoo, exist, some more widely, or more generally, known than others. In the Lower Karoo, going from west to east, they are the Tankwa Karoo, the Moordenaarskaroo, the Koup, the Vlakte, and the Camdeboo Plains. The Hantam, Kareeberge, Roggeveld, and Uweveld are the better known subregions of the Upper Karoo, though most of it is simply known as the Upper Karoo, especially in the north. (e.g. the Witteberg and Anysberg Mountains) creating multiple flat-topped hills, or Karoo Koppies, which are iconic of the Great Karoo.

The vegetation of the Upper is similar to the Lower Karoo, so few people make a distinction between the two.

The main highway (the N1) and railway line from Cape Town to the north enter the Lower Karoo from the Hex River Valley just before Touws River and follow a course about south of the Great Escarpment up to Beaufort West. Thereafter, they gradually ascend the Great Escarpment along a broad valley to Three Sisters on the Central Plateau and the Upper Karoo.

Turning north from the N1 between Touws River and Beaufort West, at Matjiesfontein, the road ascends the Great Escarpment through the Verlatenkloof Pass to reach Sutherland, at above sea level, which is reputedly the coldest town in South Africa with average minimum temperatures of during winter. Parts of the eastern Mpumalangan Highveld do at times experience lower temperatures than Sutherland, but not as consistently as Sutherland does. To the north, still on the Plateau, and north-west of Carnarvon, seven radio dishes form part of the Square Kilometer Array which will, 2500 in total, be scattered in other parts of South Africa and Australia, to survey the southern skies at radio frequencies. Our galaxy, the Milky Way, one of the main targets of this enterprise, is best viewed from the Southern Hemisphere.

The Upper Karoo is indeed an ideal site for an astronomical observatory. This is not only because of the clear skies, absence of artificial lights, and high altitude, but also because it is tectonically completely inactive (meaning that there are no fault lines or volcanoes nearby,

Klein Karoo

thumb|right|400 px|Farmlands along the well-watered, fertile foothills of the more than high [[Swartberg|Swartberg Mountains (in the background) along the northern strip of the Klein Karoo]]

The Klein Karoo is separated from the Great Karoo by the Swartberg Mountain range.

Geographically, it is a long valley, only wide, formed by two parallel Cape Fold Mountain ranges, the Swartberg to the north, and the continuous Langeberg-Outeniqua range to the south. The northern strip of the valley, within from the foot of the Swartberg mountains is least karoo-like, in that it is a well-watered area both from the rain and the many streams that cascade down the mountain, or through narrow defiles in the Swartberg from the Great Karoo. The main towns of the region are situated along this northern strip of the Klein Karoo: Montagu, Barrydale, Ladismith, Calitzdorp, Oudtshoorn, and De Rust, as well as such well-known mission stations such as Zoar, Amalienstein, and Dysselsdorp.

The southern wide strip, north of the Langeberg range, is as arid as the western Lower Karoo, except in the east, where the Langeberg range (arbitrarily) starts to be called the Outeniqua Mountains.

The Klein Karoo can only be accessed by road through the narrow defiles cut through the surrounding Cape Fold Mountains by ancient, but still flowing, rivers. A few roads traverse the mountains over passes, the most famous and impressive of which is the Swartberg Pass between Oudtshoorn in the Klein Karoo and Prince Albert on the other side of the Swartberg mountains in the Great Karoo. Also, the main road between Oudtshoorn and George, on the coastal plain, crosses the mountains to the south via the Outeniqua Pass. The only exit from the Klein Karoo that does not involve crossing a mountain range is through the long, narrow Langkloof valley between Uniondale and Humansdorp, near Plettenberg Bay.

Geology of the Karoo

The Great Karoo

thumb|left|300 px|A schematic geological map of the outcrops (surface exposures) of the Karoo Supergroup rocks in Southern Africa: The location and approximate structure of the Cape Fold Mountains are also diagrammatically indicated for reference purposes.

In geological terms, the Karoo Supergroup refers to an extensive and geologically recent (180–310 million years old) sequence of sedimentary and igneous rocks,

Although almost the whole of the Great Karoo is situated on Karoo Supergroup rocks, the geological Karoo rocks extend over a very much larger area, both within South Africa and Lesotho, but also beyond its borders and onto other continents that formed part of Gondwana. Icebergs that had calved from the glaciers and ice sheets to the north deposited a thick layer of mud containing dropstones of varying origins and sizes into this basin. This became the Dwyka Group consisting primarily of tillite, the lowermost layer of the Karoo Supergroup.

After the Beaufort period, Southern Africa (still part of Gondwana) became an arid sand desert with only ephemeral rivers and pans. These sands consolidated to form the Stormberg Group, the remnants of which are found only in the immediate vicinity of Lesotho. Several dinosaur nests, containing eggs, some with dinosaur fetal skeletons in them, have been found in these rocks, near what had once been a swampy pan.

Finally, about 180 million years ago, volcanic activity took place on a titanic scale. This brought an end to a flourishing reptile evolution.

The second special geological feature that marks the Klein Karoo is the fault line along the southern edge of the Swartberg Mountains. The Swartberg Mountains were lifted up along this fault, to such an extent that in the Oudtshoorn region, the rocks that form the base of the Cape Supergroup are exposed. These are locally known as the Cango Group, but are probably continuous with the Malmesbury Group that forms the base of Table Mountain on the Cape Peninsula, and similar outcrops in the Western Cape.

they have coined their biomes succulent Karoo and the Nama Karoo, although both, like the geological Karoo Supergroup, are more extensive than the geographical or historical Karoo described in South African atlases and guide books (compare the map on the right with the map at the beginning of the article).

Succulent Karoo biome

The succulent Karoo biome runs along the West Coast, from approximately Lamberts Bay northwards to over 200 km into southern Namibia. It starts in the south just north of the sandveld geographical region, about 250 km north of Cape Town, and continues through Namaqualand, the Richtersveld, immediately south of the Orange River, and on into the Namaqualand or Namaland region of southern Namibia. None of these regions is ever referred to, either geographically or locally, as "Karoo". It incorporates nearly the whole of the historical and geographical Great Karoo, but also includes a portion of southern Namibia's Namaqualand, and South Africa's Bushmanland (both local geographical names, not names of biomes). to the south and the savannah biome to the north. It is defined primarily by the dominance of dwarf (less than 1 m high) shrubs with a co-dominance of grasses especially towards the north-east and east where it grades into the grassland biome of the highveld and the Eastern Midlands. It is hunted by falconiformes and Verreaux's eagles. Its numbers have been consistently lowering due to destruction of its habitat. They are unique relative to similar species through how they are polygamous and how each female can only produce one or two offspring per year. black-backed jackal (6–10 kg), are arguably the largest predators likely to be seen in the Great Karoo today. Leopards (20–90 kg) do occur, especially in the mountains, but are very secretive, so are rarely seen. The two species are, therefore, rarely seen in the same habitat. The quagga is closely related to Burchell's zebra, and appears also to have been confined to the plains.

The mountain zebra occurred in the mountain regions of the Cape Fold Belt and along the southern portion of the Great Escarpment. Thus, they were endemic to, amongst others, the western Lower Karoo and the Klein Karoo. However, they were hunted to near extinction, leaving fewer than 100 individuals by the 1930s. Conservation efforts since then brought their numbers up to 1200 by 1998, mainly by concentrating these zebra in nature reserves and protected areas, the most well-known of these being the Mountain Zebra National Park near Cradock in the Great Karoo. Cape mountain zebras are still found in protected areas managed by Cape Nature, including the Kamanassie and Gamkaberg Nature Reserves.

The ostrich is found throughout Africa, but the most handsome specimens came from the Klein Karoo, where the dry weather, but plentiful water in the streams formed an ideal habitat for these large, flightless birds. Here, they grow to over 2 m in height, and weigh over 100 kg. The male's feathers have been prized by many cultures in Africa, Europe, and Asia over thousands of years. The new line started in Worcester and entered the Lower Karoo through the Hex River valley, where it followed a course almost midway between the Swartberg Mountains to the south and the Great Escarpment to the north. Along the way, it passed through the quaint Victorian village of Matjiesfontein, with the historic Lord Milner Hotel, which is still operational today. The railway reached this point in 1878, before proceeding to Beaufort West at the foot of the Great Escarpment. From there, it reached the top of the African Plateau near Three Sisters along a valley with such a low gradient that passengers were (and still are) hardly aware that they were ascending the Great Escarpment. From there it continued through the Upper Karoo, to De Aar, and crossed the Orange River at Hopetown, where South Africa's first diamond, the Eureka Diamond, was found. The Orange River, at this point, forms the local unofficial boundary between the Great Karoo and the Highveld.

Robert W. Service, in his poem "The Younger Son", imagines an emigrant at the end of a hard day: "A snow-peak of the Winterberg in crimson splendor gleams/The shadow deepens down on the karroo."

Rudyard Kipling, in his 1901 poem "Bridge-Guard in the Karroo", evoked the loneliness experienced by blockhouse soldiers at Ketting station on the Dwyka River while guarding the Karoo railway track, a lifeline during the South African War.

File:Karoo national park.jpg|The Nuweveld Mountains near Beaufort West

File:Karoo National Park.jpg|The Lower Karoo

File:Valley of Desolation 02 (3547568381).jpg|The Valley of Desolation near Graaff-Reinet

File:Karoo Koppies.png|Typical Karoo koppies near Cradock

File:Farmhouse in the Northern Cape (Karoo).jpg|Farmhouse in the Tankwa Karoo

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References

External links

http://www.karoospace.co.za
Karoo, South Africa