The Onverwacht series or Onverwacht group is a greenstone

Greenstone belt

Greenstone belts are zones of variably metamorphosed mafic to ultramafic volcanic sequences with associated sedimentary rocks that occur within Archaean and Proterozoic cratons between granite and gneiss bodies....

 mountain formation from the Archean

Archean

The Archean , also spelled Archeozoic or Archæozoic) is a geologic eon before the Paleoproterozoic Era of the Proterozoic Eon, before 2.5 Ga ago. Instead of being based on stratigraphy, this date is defined chronometrically...

 eon in the Kaapvaal craton

Kaapvaal craton

The Kaapvaal craton , along with the Pilbara craton of Western Australia, are the only remaining areas of pristine 3.6-2.5 Ga crust on Earth...

 in South Africa

South Africa

The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

 and Swaziland

Swaziland

Swaziland, officially the Kingdom of Swaziland , and sometimes called Ngwane or Swatini, is a landlocked country in Southern Africa, bordered to the north, south and west by South Africa, and to the east by Mozambique...

.

A well known part of the Onverwacht series is visible in the Komati

Komati River

The Komati River is a river in South Africa, Swaziland and Mozambique. It is long, with a drainage basin in size. Its mean annual discharge is 111 m³/s at its mouth...

 valley, located in the east of the Transvaal

Transvaal Province

Transvaal Province was a province of the Union of South Africa from 1910 to 1961, and of its successor, the Republic of South Africa, from 1961 until the end of apartheid in 1994 when a new constitution subdivided it.-History:...

 region.

The Onverwacht series can be divided into two subgroups with six formations:

• Geluk subgroup
  • Swartkoppie formation (920m)
  • Kromberg formation (1920m)
  • Hooggenoeg formation (4850m)
• Tjakastad subgroup
  • Komati formation (3500m)
  • Theespruit formation (1980m)
  • Sandspruit formation (3200m)

The fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

s found in the Onverwacht series are among the oldest found on earth

External links

Der Barberton Greenstone Belt und Komatiite