The Kalahari Craton is a

craton A craton (, , or ; from grc-gre, κράτος "strength") is an old and stable part of the continental lithosphere, which consists of Earth's two topmost layers, the crust and the uppermost mantle. Having often survived cycles of merging an ...

, an old and stable part of the

continental lithosphere A lithosphere () is the rigid, outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust and the portion of the upper mantle that behaves elastically on time scales of up to thousands of years or ...

, that occupies large portions of

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. It is bounded to the south by of coastline that stretch along the Atlantic Ocean, South Atlantic and Indian Oceans; to the ...

Botswana Botswana (, ), officially the Republic of Botswana ( tn, Lefatshe la Botswana, label= Setswana, ), is a landlocked country in Southern Africa. Botswana is topographically flat, with approximately 70 percent of its territory being the Kalaha ...

Namibia Namibia (, ), officially the Republic of Namibia, is a country in Southern Africa. Its western border is the Atlantic Ocean. It shares land borders with Zambia and Angola to the north, Botswana to the east and South Africa to the south and ea ...

and

Zimbabwe Zimbabwe (), officially the Republic of Zimbabwe, is a landlocked country located in Southeast Africa, between the Zambezi and Limpopo Rivers, bordered by South Africa to the south, Botswana to the south-west, Zambia to the north, and ...

. It consists of two cratons separated by the

Limpopo Belt The Limpopo Belt is located in South Africa and Zimbabwe, runs E-NE, and joins the Kaapvaal Craton to the south with the Zimbabwe Craton to the north. The belt is of high-grade metamorphic rocks that have undergone a long cycle of metamorphism and ...

: the larger

Kaapvaal Craton The Kaapvaal Craton (centred on Limpopo Province in South Africa), along with the Pilbara Craton of Western Australia, are the only remaining areas of pristine 3.6–2.5 Ga (billion years ago) crust on Earth. Similarities of rock records fr ...

to the south and the smaller

Zimbabwe Craton The Zimbabwe Craton is an area in Southern Africa of ancient continental crust, being a part of the ancient continent of Western Gondwana, with rocks dating back to the early Archean Eon, possibly as early as 3.46 billion years ago ( Ga.). The cra ...

to the north. The Namaqua Belt is the southern margin of the Kaapvaal Craton. Parts of the Kalahari Craton are now in East Antarctica (the

Grunehogna Craton Vaalbara was an Archean supercontinent consisting of the Kaapvaal Craton (now in eastern South Africa) and the Pilbara Craton (now in north-western Western Australia). E. S. Cheney derived the name from the last four letters of each craton's name ...

) and West Antarctica (

Haag Nunataks The Haag Nunataks () in Antarctica are a group of three low elevations aligned nearly north–south. The dominant central nunatak and the southern elevation have definite rock exposures; the minor northern elevation may be entirely snow-covered. T ...

) and the

Falkland Islands The Falkland Islands (; es, Islas Malvinas, link=no ) is an archipelago in the South Atlantic Ocean on the Patagonian Shelf. The principal islands are about east of South America's southern Patagonian coast and about from Cape Dubouze ...

. The name was first introduced by .

Formation

Following a terminology introduced in 2008, the Archaean-Palaeoproterozoic core of the craton is called the Proto-Kalahari Craton. This core plus accreted Mesoproterozoic crust and dispersed non-African fragments compose the Kalahari Craton. Before the

Pan-African Orogeny The Pan-African orogeny was a series of major Neoproterozoic orogenic events which related to the formation of the supercontinents Gondwana and Pannotia about 600 million years ago. This orogeny is also known as the Pan-Gondwanan or Saldanian Oro ...

, the Kalahari Craton was much larger than it is today, but its sutures and therefore its extent are difficult to locate due to later overprinting. The Kaapvaal Craton, Zimbabwe Craton, and Limpopo Belt are made of Archaean

terrane In geology, a terrane (; in full, a tectonostratigraphic terrane) is a crust (geology), crust fragment formed on a tectonic plate (or broken off from it) and Accretion (geology), accreted or "Suture (geology), sutured" to crust lying on another pla ...

s and contain crust at least 3.2 and are underlain by a thick () layer of buoyant mantle that is producing garnets and diamonds. During the Palaeoproterozoic the northwest margin of the Archaean core grew by accretion and had formed a Proto-Kalahari Craton by 1.75 Ga. During the period 1.4–1.0 Ga subduction occurred along the northwest margin followed by continental collisions along the eastern and southern margins. By this time enough Mesoproterozoic crust had accreted to transform the Kalahari Craton. At 1.11 Ga, during the assembly of the supercontinent Rodinia, the Kalahari Craton was affected by the Umkondo-Borg Large Igneous Province. At 1.15–.98 Ga the Kalahari Craton collided with the eastern margin of

Laurentia Laurentia or the North American Craton is a large continental craton that forms the ancient geological core of North America. Many times in its past, Laurentia has been a separate continent, as it is now in the form of North America, althoug ...

References

Bibliography

* * * * {{DEFAULTSORT:Kalahari Craton Cratons Geology of Botswana Geology of Namibia Geology of South Africa Geology of Zimbabwe Historical continents

Craton A craton (, , or ; from grc-gre, κράτος "strength") is an old and stable part of the continental lithosphere, which consists of Earth's two topmost layers, the crust and the uppermost mantle. Having often survived cycles of merging an ...

Formation

See also

References

Bibliography