Kandi Fault Zone

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The Kandi fault zone is a southern extension of the Hoggar fault zone in West Africa, with splays in Benin, Togo and southeastern Ghana. It lies at the southern end of the Trans Saharan belt, a lineament that extends in a southwest direction from Algeria to Benin. The Kandi fault zone is identified with the Sobral fault in northeastern Brazil, considered to be the northern section of the Trans Brazilian Lineament. [1]

West Africa Westernmost region of the African continent

West Africa is the westernmost region of Africa. The United Nations defines Western Africa as the 16 countries of Benin, Burkina Faso, Cape Verde, The Gambia, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Liberia, Mali, Mauritania, the Niger, Nigeria, Senegal, Sierra Leone and Togo, as well as the United Kingdom Overseas Territory of Saint Helena, Ascension and Tristan da Cunha. The population of West Africa is estimated at about 362 million people as of 2016, and at 381,981,000 as of 2017, of which 189,672,000 are female and 192,309,000 male.

Benin country in Africa

Benin, officially the Republic of Benin and formerly Dahomey, is a country in West Africa. It is bordered by Togo to the west, Nigeria to the east, and Burkina Faso and Niger to the north. The majority of its population lives on the small southern coastline of the Bight of Benin, part of the Gulf of Guinea in the northernmost tropical portion of the Atlantic Ocean. The capital of Benin is Porto-Novo, but the seat of government is in Cotonou, the country's largest city and economic capital. Benin covers an area of 114,763 square kilometres (44,310 sq mi) and its population in 2016 was estimated to be approximately 10.87 million. Benin is a tropical nation, highly dependent on agriculture, and is a large exporter of cotton and palm oil. Substantial employment and income arise from subsistence farming.

Togo Country in Africa

Togo, officially the Togolese Republic, is a country in West Africa bordered by Ghana to the west, Benin to the east and Burkina Faso to the north. The sovereign state extends south to the Gulf of Guinea, where its capital Lomé is located. Togo covers 57,000 square kilometres, making it one of the smallest countries in Africa, with a population of approximately 7.6 million.

The Kandi fault is a band about 400 m thick of ultramylonites with shallow-plunging stretching lineations. [2] The nature of the deposits of the Kandi Basin indicate that they were formed during the melting of the wide ice sheet that overlay the Afro-Arabian Shield during Late Ordovician times. [3] Kandi lies at the southern end of the Trans Saharan Kandi/4°50' lineament, which represents a suture resulting from an oblique collision between the West African craton and the Sao Francisco / Congo craton. The Sobral shear zone of the Transbrasiliano lineament is considered a continuation of this lineament. [4] The fit between the continental margins of South America and Africa is poor in this region, in contrast to the excellent fit to the west and south, but this can be explained by splay faults created during the separation of the continents. [5]

Mylonite fine-grained, compact metamorphic rock produced by dynamic recrystallization of the constituent minerals

Mylonite is a fine-grained, compact metamorphic rock produced by dynamic recrystallization of the constituent minerals resulting in a reduction of the grain size of the rock. Mylonites can have many different mineralogical compositions; it is a classification based on the textural appearance of the rock.

The Ordovician is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.2 million years from the end of the Cambrian Period 485.4 million years ago (Mya) to the start of the Silurian Period 443.8 Mya.

South America A continent in the Western Hemisphere, and mostly in the Southern Hemisphere

South America is a continent in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. It may also be considered a subcontinent of the Americas, which is how it is viewed in the Spanish and Portuguese-speaking regions of the Americas. The reference to South America instead of other regions has increased in the last decades due to changing geopolitical dynamics.

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Vaalbara Archaean supercontinent from about 3.6 to 2.7 billion years ago

Vaalbara was an Archean supercontinent consisting of the Kaapvaal Craton and the Pilbara Craton. E. S. Cheney derived the name from the last four letters of each craton's name. The two cratons consist of crust dating from 2.7 to 3.6 Gya, which would make Vaalbara one of Earth's earliest supercontinents.

North China Craton A continental crustal block in northeast China, Inner Mongolia, the Yellow Sea, and North Korea

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São Francisco Craton An ancient craton in the eastern part of South America with outcrops in Minas Gerais and Bahia, Brazil

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Central African Shear Zone

The Central African Shear Zone (CASZ) is a wrench fault system extending in an ENE direction from the Gulf of Guinea through Cameroon into Sudan. The structure is not well understood. As of 2008, there was still no general agreement about how the individual shears along the lineament link up.

The Trans Brazilian Lineament (TBL), or Transbrasiliano Lineament, is a major shear zone that developed in the Precambrian period, and that has been reactivated several times since then, mostly recently during the Mesozoic. Movement along the shear zone helps explain how the South American continent could have fitted tightly to the African continent before the breakup of Gondwana.

The Pharusian Ocean is an ancient ocean that existed from 800 to 635 million years ago, between the break-up of the Rodinia supercontinent and the start of formation of the Gondwana supercontinent.

The Sobral fault is a major fault in the Borborema geological province of northeastern Brazil, a part of the Transbrasiliano lineament. It is commonly correlated with the Kandi fault in Benin, east of the West African craton. The fault lies in the northwest of Ceará state. It appears to have formed late in the orogeny when the West African craton engaged with the Congo craton, and to have allowed significant dextral strike-slip movement. It was reactivated when South America was breaking away from Africa. In this later phase, a sinistral shear movement of about 100 km seems to have taken place during and after the break-up.

The Foumban Shear Zone, or Central Cameroon Shear Zone (CCSZ), is a fault zone in Cameroon that has been correlated with the Pernambuco fault in northeastern Brazil, which splays from the Trans-Brazilian Lineament. It is part of the Central African Shear Zone (CASZ) and dates to at least 640 million years ago. The zone was rejuvenated several times, usually with a dextral movement, before and during the opening of the South Atlantic in the Cretaceous period.

The Pernambuco Fault or Pernambuco Shear Zone in northeastern Brazil is a fault radiating from the Trans Brazilian Lineament eastwards to the coast, a major geological feature.

The Mwembeshi Shear Zone is a ductile shear zone about 550 million years old that extends ENE-WSW across Zambia. In Zambia, it separates the Lufilian Belt to the northwest from the Zambezi Belt to the southeast. It is associated with a sinistral strike slip movement.

References

  1. ↑ Attoh & Brown 2008.
  2. ↑ Pankhurst 2008, pp. 62.
  3. ↑ Konate et al. 2003.
  4. ↑ Pankhurst 2008, pp. 58.
  5. ↑ Fairhead, Bournas & Raddadi 2007, pp. 1.

Sources

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