por what is the Atlantic ridge?
The atlantic ridgemid-Atlantic or mid-Atlantic ridge, is a volcanic ridge that divides the Atlantic Ocean from north to south. It is submerged in water, so the ridge causes the surface of the Atlantic Ocean to break into several islands that can be found grouped in the middle of the sea.
Of all the islands that are located from north to south, only those of San Pedro and San Pablo have volcanic origin, unlike Iceland, Ascension, Tristán da Cunha, Santa Elena and Bouvet, which are not.
Atlantic ridge extension
The largest part of the mid-Atlantic ridge occupies about 3,000 to 5,000 meters below the sea.
From its seabed there is a long mountain range whose peaks rise to various altitudes, ranging from 1,000 to 3,000 meters. In width it occupies approximately 1,500 kilometers, from east to west.
The mid-Atlantic ridge has a large cleft, a deep valley that runs the entire length of its crest. Its estimated width is around 10 kilometers and its walls are walls that reach up to 3 kilometers.
This valley forms a natural border that at the bottom of the Atlantic Ocean divides the two tectonic plates that meet on Earth. Its widening occurs constantly, at a rate of 2 centimeters per year.
Due to the high volcanic activity that it has, the magma, when it rises, cools and later becomes a new layer that joins the ocean floor.
It has fracture zones. The best known is the Romansh fracture, which runs in an east-west direction. It also has discontinuities, whose extension exceeds 100 kilometers in length.
In the North Atlantic, it divides the Eurasian and North American plates, and in the south, it divides the African and South American plates.
Features of the atlantic ridge
geological features
– The Atlantic ridge basically consists of a very deep valley whose shape is sinusoidal, a long meandering line interrupted in several of its sections by volcanic action and underwater earthquakes, frequent in that part of the Earth.
– This line leaves a clear separation in the tectonic layers that are located in the continents it crosses.
– The terrain of the Atlantic ridge is formed by magma trying to rise to the surface, but encountering ocean waters. The magma cools and forms a wall of hardened lava, which becomes the new layer of soil on the seabed. New centimeters are added each year.
– The Mid-Atlantic ridge is subdivided into two branches: a northern one (the North Atlantic Ridge), and a southern one (the South Atlantic Ridge). In the latter there is a kind of maritime trench, or a fracture known as the Romanche, which sinks to 7,758 meters. It is one of the deepest underwater sites in the Atlantic Ocean.
Geographic characteristics
– It starts in Iceland and ends in the South Atlantic Ocean. It makes a link with southern Africa through the Cape of Good Hope, and passes through the Indian Ocean ridge.
– From there it passes to the south of Australia through the ridge of the Pacific Ocean, which is extended throughout its southern and eastern zone, until it reaches the territory of Mexico, where it touches the western coast of the United States, in California.
– There are secondary ridges to the Atlantic, which can be transversal or parallel. These include the Hawaiian Ridge, the Pacific Ridge, and the Kerguelen Ridge.
– The ridges that maintain their tectonic activity occupy areas directly proportional to the continents with which they border.
– Along its route there are many islands and archipelagos of volcanic origin. In total, there are nine islands. On the North Atlantic Ridge are Iceland, San Pedro, the Azores, and Jan Mayen.
– On the south Atlantic ridge are the islands of Bouvet, Tristan da Cunha, Gough, Santa Elena and Ascension. In the particular case of Iceland, the Atlantic ridge passes right through the middle, dividing it in half.
– The Romansh fracture draws an imaginary horizontal line through the Equator. The edges of the Gulf of Guinea and the northeastern coast of Brazil fit together and indicate that Africa and the Americas were continents that were joined.
References
Mgar: History, Navigation. Seabed 2; Atlantic Ridge. Canary islands spain. Retrieved from mgar.net.
Mid-Atlantic Ridge. Retrieved from geolsoc.org.uk.