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The Geology of Namibia

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The Geology of Namibia Namibia's varied geology encompasses rocks of A great variety of mineral deposits has been identi- Archaean to Phanerozoic age, thus covering more than fied throughout the stratigraphic column. Metamorphic 2600 million years of Earth history. About half of the complexes host several base and precious metal occur- country's surface area is bedrock exposure, while the rences, such as copper-molybdenum porphyry, volcano- MINISTRY OF MINES & ENERGY remainder is covered by Cenozoic deposits of the Kalahari exhalative copper-lead-zinc and gold, volcanogenic copper, and Namib Deserts. sedimentary-exhalative lead-zinc, shear-zone gold and Highly deformed gneisses, amphibolites, diverse beryllium-niobium-tantalum pegmatites. Meso- to metasediments and associated intrusive rocks are exposed Neoproterozioc rocks locally contain extensive red-bed within several metamorphic inliers in the central and copper, while calc-alkaline granitoid intrusives of that age northern parts of the country, and represent the oldest rocks have potential for porphyry and hydrothermal copper, as of Archaean to Palaeoproterozoic age (ca. 2600 to 1600 well as for vein-type gold mineralisation. Ma) in Namibia. These include the volcanic Haib In the Neoproterozoic Damara Orogen and Gariep Subgroup and Vioolsdrif Granite Suite along the Orange Belt, mineralisation is associated with successive phases of River, the volcano-sedimentary Khoabendus and intracontinental rifting (copper, graphite), spreading and the THE GEOLOGY OF Rehoboth Groups, as well as the Kunene and Grootfontein formation of passive continental margins (volcano- Igneous Complexes in the north. exhalative base metals, e.g. Rosh Pinah {1}, Skorpion {2}); NAMIBIA The Mesoproterozioc (1600 to 1000 Ma) is repre- sedimentary-exhalative lead-zinc, e.g. Tsongoari {3}; sented by the Namaqua Metamorphic Complex in the glaciomarine iron-mangenese, e.g. Otjosondu {4}; sedi- south, which comprises granitic gneisses, metasediments ment-hosted copper, e.g. Klein Aub {5}). Besshi-type and felsic to mafic instrusions, and by the volcano- copper-pyrite (e.g. Otjihase {6}) is related to mid-ocean N A M I B I A G 3 sedimentary Sinclair Supergroup of central Namibia, with ridge development, whereas subsequent subduction led to E 0 O 9 1 L - O its associated granites (e.g. Gamsberg Suite). the localised enrichment of carbonate-hosted base metals Y G E I C V The coastal and intracontinental arms of the late (e.g. Tsumeb {7}, Kombat {8}), uraniferous granites A R L U Proterozoic Damara Orogen (ca. 800 to 500 Ma) underlie (Rössing {9}), rare metal and tin pegmatites (Uis {10}, S much of northwestern and central Namibia, with stable Rubicon {11}, as well as skarn tungsten and gold (Navachab platform carbonates in the north, and diverse {12}, Otjikoto {13}). metasedimentary rocks pointing to more variable Coal measures are hosted in Palaeozoic rocks of the depositional conditions further south. The volcano- Karoo Supergroup, while Cretaceous anorogenic com- GEOLOGICAL SURVEY sedimentary Gariep Belt along the southwestern coast plexes, contain a variety of semi-precious stones, fluorite OF NAMIBIA represents the southern extension of the Damara Orogen. (Okorusu {14}), apatite, rare earth elements, iron and other Shallow-marine clastic sediments of the Nama Group, base metals. Following the discovery of the offshore Kudu which covers parts of southern Namibia, are derived from gas field of Cretaceous age {15}, hydrocarbon exploration 6 Aviation Road orogenic uplift of the Damara and Gariep Belts. also intersected oil-prone source rocks in boreholes. Windhoek Sedimentary and volcanic rocks of the Cenozoic epigenetic uranium mineralisation occurs in Namibia Carboniferous to Jurassic Karoo Supergroup occur in the calcretes above basement rocks in the Namib Desert (e.g. Aranos, Huab and Waterberg Basins, in the southeastern Langer Heinrich {16}), and salt is produced by solar Contact details: and northwestern parts of the country. They are exten- seawater evaporation (e.g. Walvis Bay and Swakopmund sively intruded by dolerite sills and dykes which, in Salt Works {17}). Postal: Private Bag 13297, collusion with predominantly basaltic volcanism The most important mineral resources of the Windhoek (Etendeka Plateau) and a number of subvolcanic com- country, however, are the Cenozoic diamondiferous beach Tel.: +264-(0)61-284 8111 plexes (e.g. Spitzkoppe, Erongo), herald the break-up of and river gravels, which are exploited along the Orange Fax: +264-(0)61-249144 the Gondwana Supercontinent, and the formation of the River (e.g. Daberas {18}) as well as the southwestern coast, Web: www.mme.gov.na South Atlantic during the Cretaceous (ca. 130 Ma). The both offshore and onshore {19}. With mining techniques currently last chapter of Namibia's geological history is being developed to suit the unique conditions of these told by the widespread Palaeogene to Recent (< 50 Ma) deposits, Namibia has become one of the world's top five sediments of the Namib and Kalahari Groups. producers of diamonds. .
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