Geology of Namibia

Damara Belt separating the Congo and Kalahari Cratons

The geology of Namibia encompasses rocks of

The country is famous for its mineral deposits of Tsumeb, as well as many geological sites of interest, from paleontological, geomorphological and volcanic character. Due to the exposure of the formations in a desert climate and the former German colony, the geology of Namibia is relatively well studied compared to the more tropical less exposed northern neighbors.

Stratigraphy and tectonics

Large areas of the Namibian geology exposed onshore are associated with the Late Proterozoic

Kunene River the oldest rocks of the country belong to the Paleoproterozoic (about 2,100 Ma) Epupa Metamorphic Complex. Only slightly younger are metamorphic rocks of the Huab Complex west of Outjo. Similar ages are also recorded from rocks of the Grootfontain Metamorphic Complex in the northeast of the country.^[2]

The Rehoboth-Sinclair Complex in Namibiaʼs southwest is of late Paleoproterozoic or Mesoproterozoic age. The Epupa and Huab Complexes were attached to the Congo Craton, whilst the Grootfontain and the volcano-sedimentary formations of the Rehoboth-Sinclair Complexes were assembled with the Kalahari Craton. The Namaqua Metamorphic Complex consists of metasediments originally eroded from the Congo and Kalahari Cratons. Granitic and metabasic intrusions also occur. It is of Mesoproterozoic age and covers large areas in the south and southwest of the country. Of Neoproterozoic age are the rocks of the Damara Orogenic Belt, which are widespread in central and northern Namibia. These are high grade metamorphics, but granitic intrusions are also frequent. In the Neoproterozoic Damara Orogen and Gariep Belt, mineralisation is associated with successive phases of intracontinental rifting (copper, graphite), spreading and the formation of passive continental margins.^[3] The overlying rocks of the Nama Group in central southern Namibia consist of marine sediments indicating a shallow shelf environment, deposited during the Ediacaran and earliest Cambrian. The clastic components of the Nama Group were mainly derived from the Damara Orogenic Belt, while the basal pelites and carbonates have eastern provenance areas.

No deposition is recorded from the Cambrian until the beginning of the

dyke swarms, which, together with extensive basaltic volcanism and alkaline sub-volcanic intrusions, are related to the breakup of Gondwana, and the formation of the South Atlantic Ocean during the Cretaceous. The currently last chapter of the geological history of the country is represented by the widespread Cenozoic to recent deposits of the Kalahari Sequence

.

Sedimentary basins

Namibia hosts the following sedimentary basins:

On/offshore	Name	Location	Notes
Onshore	Orupembe Basin	Kunene Region	^[4]
	Huab Basin	Kunene Region	^[4]
	Etosha, Rundu or Owambo Basin	Kavango Region Otjozondjupa Region Omaheke Region	^[4]^[5]
	Waterberg Basin	Otjozondjupa Region	^[4]^[5]
	Kalahari or Nama Basin	Omaheke Region Hardap Region ǁKaras Region	^[4]^[5]
	Karasberg or Warmbad Basin	ǁKaras Region	^[4]^[5]
	Dordabis Basin	Khomas Region Omaheke Region	^[6]
	Witvlei Basin	Omaheke Region
	Klein Aub Basin	Erongo Region
	Sinclair Basin	Hardap Region
Offshore	Namibe Basin	Northwest	^[5]
	Walvis Basin	Northwest
	Lüderitz Basin	West
	Orange Basin	Southwest

Paleontology

While fossiliferous stratigraphic units are relatively rare in Namibia, the unique

trackways.^[7] The Eocene Buntfeldschuch and Langental Formations contain numerous fossil fish and the Early Miocene Elisabeth Bay Formation shows a diverse fauna with snake and mammal fossils.^[8]^[9]

Roter Kamm crater

The

meteor that hit it was approximately the size of an SUV.^[10]

Economic geology

Blood red cerussite due to inclusions of cuprite

Tsumeb is a world-famous site for minerals. In the district, 309 different minerals are recorded and the area hosts 72 type localities of minerals and one first reported locality of an unapproved mineral, zinclavendulan, a variety of lavendulan.^[11] The minerals arsentsumebite (Pb₂Cu(AsO₄)(SO₄)(OH)) and tsumebite (Pb₂Cu(PO₄)(SO₄)(OH)) are named after Tsumeb.^[12]^[13]

Targets for mineral exploration have been identified throughout the stratigraphic column. Metamorphic complexes host a variety of prospective environments such as

red bed copper, while calc-alkaline units of the same age have potential for porphyry and hydrothermal copper, as well as vein-type gold mineralization. Namibia is one of the major producers of diamonds, 95% of which are of gem quality. The bulk of the countryʼs known diamonds occur along the southern coastline, north of the Orange River mouth.^[14]

The diamonds originated in the interior of southern Africa and were transported by the Orange River to the Atlantic coast, where they were deposited within beach sediments. Almost the entire coastline is covered by exploration and mining licenses. Offshore mining techniques have been pioneered in Namibia and the country has firmly been established as the world leader in marine diamond mining. Inland, in the vicinity of Gibeon, 60 barren pipes of kimberlite of post-Karoo age have been identified. The northeast of the country also hosts some kimberlites, which are currently being explored for their diamond potential. The main occurrences of gold are in the Karibib and Rehoboth regions, the Omaruru area and the Kunene region. Silver is present in several deposits mined principally for their copper, lead and zinc contents.

It is found in the ore bodies of

Rössing and Valencia are of granitic origin. In the mid-2000s, Rössing was the countryʼs only producer of uranium. Major base metal production in Namibia includes copper, lead and zinc. Large-scale mining of base metals, especially copper, plays an important role in the economy of the country. Copper occurs at several locations, but is dominated by the Damara deposits: Otavi Mountainland (including the defunct Tsumeb Mine) and the Matchless Amphibolite Belt of the Swakop Group. Minor amounts come from Rosh Pinah. A feasibility study of the Skorpion zinc project has confirmed that Skorpion could rank as one of the worldʼs largest integrated zinc mining and refining operations. Haib, at the border with South Africa, is a classic porphyry copper-gold-molybdenum deposit featuring oxide and sulphide copper with a predominance of chalcopyrite

in the sulphide ores.

Salt is recovered on a large scale from coastal solar evaporation pans in the

Marble, granite and other dimension stone for export or local processing are produced between Swakopmund and Karibib.^[15]

Petroleum geology

The Namibian Atlantic margin is conjugate with the Pelotas Basin of Rio Grande do Sul and northeastern Uruguay. Both basins are compared to their northern counterparts, for the Walvis Basin in Namibia the Kwanza Basin of Angola, and for the Pelotas Basin the Santos Basin of Brazil, underexplored. Apart from the discovery of the offshore Kudu Gas Field, exploration intersected oil-prone source rocks in boreholes, of merely five wells until 2004.^[16] The Walvis Basin is bound by the Walvis Ridge, which formed a barrier in the opening of the Southern Atlantic in the Aptian leading to salt basins to the north and basins without evaporite deposits to the south. The ridge, in South America correlated with the Rio Grande Rise, both related with the Tristan da Cunha hotspot, also represents the boundary between volcanic and non-volcanic areas to the south and north respectively.^[17] Cenomanian-Turonian oil-prone source rocks have been penetrated by wells in the Walvis Basin.^[18]

Namibia imports all its power station requirements. A large low-grade

fluorspar, wollastonite and dimension stone.^[15]

Geological sites

Namibiaʼs geological exposures contribute to a wide variety of geological sites. Some of them have already been protected, but some are unfortunately already spoiled. A formal inventory has provided 32 sites:

Brandberg
Brukkaros Mountain
Burnt Mountain
Dieprivier
Dolerite Hills
Etendeka Plateau
Erongo
Etosha Pan
Fish River Canyon
Gamsberg
Gibeoan Meteorites
Hoba Meteorite
Kalahari Desert
Karas Mountains
Kolmanskop
Kuiseb Canyon
Lake Otjikoto and Lake Guinas

Messum
Mount Etjo
Mukorob
Namib Desert
Naukluft
Omatako Mountains
Organ Pipes
Dinosaur tracks at
Otjihaenamparero
Petrified forest, Khorixas
Sesriem Canyon
Sossusvlei
Tsondabvlei
Spitzkoppe
Twyfelfontein
Vingerklip
Waterberg

A spoiled geological monument is the

Mukorob or "Finger of God", a weather resistant remnant of a sandstone pinnacle that was left standing on its own as erosion slowly cut back the surrounding Weissrand Escarpment of the Karoo Supergroup in southern Namibia. The Mukorob consisted of a large head of sandstone supported by a narrow neck of soft, fragmented mudstone. The head was almost 12 metres (39 ft) high and weighed about 450 tonnes (440 long tons; 500 short tons). On 8 December 1988, the Mukarob collapsed, possibly due to a destructive earthquake that had occurred the previous day in Armenia

, but which was recorded strongly on the seismograph in Windhoek.

The petrified forest near

Otjihaenamparero in central Namibia; the Fish River Canyon in southern Namibia is the second largest canyon of the world and is famous for its scenic beauty.^[19]

Hoba meteorite, the largest known meteorite (as a single piece)
Aerial view of Weissrand (2019)

References

^ Kukulus, 2004, p.10
^ Schluter, Thomas (2006). Geological Atlas of Africa (PDF). Springer. pp. 172–175.
^ MME, 2011, p.1
^ ^a ^b ^c ^d ^e ^f Pickford, 1995, p.52
^ ^a ^b ^c ^d ^e Negonga, 2014, p.6
^ Borg, 1995, p.110
^ Otjihaene-Maparero farm at Fossilworks.org
^ Bogenfels at Fossilworks.org
^ Elizabethfeld at Fossilworks.org
^ "Roter Kamm crater". Archived from the original on 2016-03-04. Retrieved 2018-06-09.
^ Tsumeb - Mindat.org
^ Arsentsumebite - Mindat.org
^ Tsumebite - Mindat.org
^ Schluter 2006, p. 172.
^ ^a ^b Schluter 2006, p. 174.
^ Kukulus, 2004, p.146
^ Sakariassen, 2007, p.2
^ Kukulus, 2004, p.149
^ Schluter 2006, p. 175.

Bibliography

Borg, G. 1995. Metallogenesis of Neoproterozoic basins in Namibia and Botswana. Communications of the Geological Survey of Namibia 10. 109–119. Accessed 2018-08-26.
Kukulus, Matthias. 2004. A quantitative approach to the evolution of the central Walvis Basin offshore NW-Namibia: structure, mass balancing, and hydrocarbon potential (PhD thesis), 1–241. Julius-Maximilians-Universität Würzburg.
MacDonald, Francis A.; Justin V. Strauss; Catherine V. Rose; Francis O. Duda, and Daniel P. Schrag. 2010. Stratigraphy of the Port Nolloth Group of Namibia and South Africa and implications for the age of Neoproterozoic iron formations. American Journal of Science 310. 862–888. Accessed 2018-08-26.
Negonga, Martin. 2014. Acreage portfolio of Namibian sedimentary basins, 1–31.
AAPG Annual Convention
. Accessed 2018-08-26.
Pickford, Martin. 1995. Karoo Supergroup palaeontology of Namibia and brief description of a thecodont from Omingonde. Paleontologica Africana 32. 51–66. Accessed 2018-08-26.
Sakariassen, Rune. 2007. North Namibia margin: regional tectonic evolution based on integrated analysis of seismic reflection and potential field data and modelling (MSc. thesis), 1–94. University of Oslo. Accessed 2018-06-08.
Various, Authors. 2011. The Geology of Namibia, 1–2. MME. Accessed 2018-08-26.

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