Map of Benin |
Mineral resource development is controlled by the Office
Béninoise des Mines (OBEMINES). Benin has been revising its mining laws in order to attract foreign investment.
Major sources of alluvial gold and diamonds can be found in
the Birimian rocks that are found in Ghana, the Ivory Coast, Mali and Burkina Faso These rocks derive their name from the Birim
River thay are one of the main tributaries of the Pra River of Ghana. The same rocks also contain the country’s
most important diamond deposits.
Diamonds are produced in Ghana
and Mali that
are the second and third largest producers in Africa .
The gold and diamond bearing rocks are called the Birimian
Terranes that are composed of a mix 0f meta-volcanics, meta-sedimentary and
rocks that are plutonic in nature.
Almost half of the rocks found in the southern part of the West African
Craton are alkaline granites. These
rocks formed in a period of about 50 million years between 2,200 and 2,100 Ga
years ago.
It is believed the Birimian Rocks that stretch across the
countries that are to the north of the Gulf
of Guinea formed when a series of
island arcs were driven together forming a series of parallel belts that trend
to the northeast in a belt that is about 40 to 50 kilometers wide. Many of the volcanic rocks have been metamorphosed
into greenschist facies.
Although most of the gold mined in the country is recovered
by artisanal miners from the Birimian Terrane it has recently discovered more
gold is found in the overlaying conglomerate of the Tarkewian formation. The gold does not have its origin in the
Birimian Terrane.
There are several varying theories about the origin of the
Birimian Terrane. One theory holds the
rocks were formed by the collision of the Archean Cupixi-Carajas craton of the
Southern Guiana Shield. Another theory
that is more widely accepted is the terrane has it origins in a mid-oceanic
series of volcanic island arcs that formed a crust that was then thrust faulted
onto the West African Craton that was later compressed into a series of folds.
During the recent civil war in Benin
foreign investment literally dried up, but with the onset of peace it is
beginning to flow once again.
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