Tanzania Craton

Approximate location of Mesoproterozoic (older than 1.3 Ga) cratons in South America and Africa.

The Tanzania Craton is an old and stable part of the continental lithosphere in central Tanzania. Some of the rocks are over 3 billion years old.^[1]

Setting

The Tanzania Craton forms the highest part of the East African plateau.^[2] The craton is surrounded by Proterozoic mobile belts of various ages and grades of metamorphism. These include the Ubendian, Usagaran, Karagwe-Ankolean and Bukoban systems. The Mozambique Belt lies to the east.^[3] The craton divides the east and west branches of the East African Rift.^[2] The southern end of the Gregory Rift Valley terminates against the craton. The volcanic area of this rift covers the surface interface between the Mozambique orogenic fold belt and the Tanzania Craton.^[1]

Composition

The craton is a composite of several different terranes of Archaean metasediments. The Dodoman is the oldest, and others include the Nyanzian and Kavirondian. Some of the greenstone belts are more than 3 billion years old. They were intruded by granites and magmatized in different events that date back to 2.9, 2.7, 2.4 and 1.85 billion years ago.^[1] The craton mainly consists of Archaean granitic complexes, but also includes rocks from the Dodoma System in the central area, and belts of greenstone to the south and east of Lake Victoria. Gneisses, schists, quartzites, migmatites, amphibolites and granulite are also found. There was widespread intrusion of kimberlites in the Cretaceous Period, mostly in the part of the craton that lies south of Lake Victoria.^[3] This includes the Mwadui kimberlite pipe in the center of Tanzania.^[4]

References

Sources

Dawson, John Barry (2008). The Gregory rift valley and Neogene-recent volcanoes of northern Tanzania. Geological Society. ISBN 1-86239-267-6.
"GEOLOGICAL FRAMEWORK AND REGIONAL METALLOGENY OF TANZANIA" (PDF). Kilimanjaro Mining Company. Retrieved 2011-12-28.
van Straaten, Peter (2009). "Tanzania". Rocks for Crops (PDF). University of Guelph.

Major African geological formations

Plates	African Plate Somali Plate Madagascar Plate Seychelles Plate

Cratons and Shields	Arabian-Nubian Shield Congo Craton Kaapvaal Craton Kalahari Craton Saharan Metacraton Tanzania Craton Tuareg Shield West African Craton Zimbabwe Craton

Shear zones	Aswa Dislocation Broodkop Shear Zone Central African Shear Zone Chuan Shear Zones Foumban Shear Zone Mwembeshi Shear Zone Todi Shear Zone Western Meseta Shear Zone

Rifts	Afar Triangle Anza trough Bahr el Arab rift Benue Trough Blue Nile rift East African Rift Gulf of Suez Rift Lamu Embayment Melut Basin Muglad Basin Red Sea Rift Atbara rift White Nile rift

Sedimentary basins	Angola Basin Aoukar Blue Nile Basin Chad Basin Congo Basin Douala Basin El Djouf Foreland Karoo Basin Gabon Basin Iullemmeden Basin Kufra Basin Murzuq Basin Niger Delta Basin Ogaden Basin Orange River basin Ouled Abdoun Basin Owambo Basin Reggane Basin Rio del Rey Basin Sirte Basin Somali Coastal Basin Taoudeni basin Tanzania Coastal Basin Tindouf Basin

Mountain ranges	Aïr Mountains Atlas Mountains Aurès Mountains Bambouk Mountains Blue Mountains Cameroon line Central Pangean Mountains Chaillu Mountains Drakensberg Ethiopian Highlands East African mountains Great Escarpment Great Karas Mountains Guinée forestière Imatong Mountains Jebel Uweinat Loma Mountains Mandara Mountains Marrah Mountains Mitumba Mountains Nuba Mountains Rif Mountains Rwenzori Mountains Sankwala Mountains Serra da Leba Serra da Chela Teffedest Mountains Tibesti Mountains