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The Eburnean orogeny, or Eburnean cycle, was a series of
The Eburnean orogeny, or Eburnean cycle, was a series of tectonic
Tectonics (; ) are the processes that control the structure and properties of the Earth's crust and its evolution through time. These include the processes of mountain building, the growth and behavior of the strong, old cores of continents ...
, metamorphic
Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causin ...
and plutonic
Intrusive rock is formed when magma penetrates existing rock, crystallizes, and solidifies underground to form '' intrusions'', such as batholiths, dikes, sills, laccoliths, and volcanic necks.Intrusive RocksIntrusive rocks accessdate: March ...
events in what is now West Africa
West Africa or Western 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, Maurit ...
during the Paleoproterozoic
The Paleoproterozoic Era (;, also spelled Palaeoproterozoic), spanning the time period from (2.5–1.6 Ga), is the first of the three sub-divisions (eras) of the Proterozoic Eon. The Paleoproterozoic is also the longest era of the Earth's ...
era about 2200–2000 million years ago.
During this period the Birimian
The Birimian rocks are major sources of gold and diamonds that extend through Ghana, Côte d'Ivoire, Guinea, Mali and Burkina Faso. They are named after the Birim River, one of the main tributaries of the Pra River in Ghana and the country's m ...
domain in West Africa was established and structured.
Eburnian faults are found in the Eglab shield to the north of the West African craton
The West African Craton (WAC) is one of the five cratons of the Precambrian basement rock of Africa that make up the African Plate, the others being the Kalahari craton, Congo craton, Saharan Metacraton and Tanzania Craton.Jessell M.W., Liégeo ...
and in the Man Shield
The Man Shield (Leo-Man Shield or Leo-Man Craton) is a geological shield or craton in the southeast portion of the West African Craton. The shield is in part overlaid by gold-bearing Birimian formations.
Geography and Geology
The shield co ...
to the south of the craton.
There is evidence of three major Eburnean magmatic events in the Eglab shield.
Between 2210 and 2180 Ma, a metamorphosed batholith was formed in the Lower Reguibat Complex (LRC).
Around 2090 Ma, a syntectonic trondhjemitic pluton intruded into the Archaean reelects of the Chegga series. Around 2070 Ma an asthenospheric upwelling released a large volume of post-orogenic magmas.
Eburnian trends within the Eglab shield were repeatedly reactivated from the Neoproterozoic to the Mesozoic.
See also
*Geology of Ghana
The geology of Ghana is primarily very ancient crystalline basement rock, volcanic belts and sedimentary basins, affected by periods of igneous activity and two major orogeny mountain building events. Aside from modern sediments and some rocks form ...
*Geology of Ivory Coast
The geology of Ivory Coast is almost entirely extremely ancient metamorphic and igneous crystalline basement rock between 2.1 and more than 3.5 billion years old, comprising part of the stable continental crust of the West African Craton. Near the ...
*Geology of Mali
Mali is a landlocked nation in West Africa, located southwest of Algeria, extending south-west from the southern Sahara Desert through the Sahel to the Sudanian savanna zone. Mali's size is 1,240,192 square kilometers.
Desert or semi-desert ...
References
;Citations ;Sources * * Paleoproterozoic orogenies Orogenies of Africa {{tectonics-stub