Oceanic Ridge Meaning
Oceanic ridge is a continuous submarine chain of mountains that extends roughly 80,000 km (that is 50,000 miles) among all the oceans present in the world. In the ocean basin, these ocean ridges are the largest features. Geographically speaking, these oceanic ridges are the most distinct and prominent feature on the surface of the earth after the continents and oceans being the prominent ones.
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Previously these features were also referred to as the mid-ocean ridges. While the largest ocean ridge, the East Pacific Rise is quite a distance from a mid-ocean location, hence, we can say that the generalization is not exactly correct. Further, students must not confuse these oceanic ridges with aseismic ridges, which originated apart from these.
Mid Ocean Range
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A mid-ocean ridge also known as the mid-oceanic ridge is an underwater mountain range, which is formed by the action of plate tectonics. There is uplifting of the ocean floor, which is caused due to the convection currents as it rises in the mantle which is beneath the oceanic crust and here it creates magma. The creation of magma is done where the two tectonic plates meet at a divergent boundary.
These mid-ocean ridges of the world are all connected and they form a single global mid-oceanic ridge system which is a part of every ocean that makes up the mid-oceanic ridge system. Here the longest mountain range in the world is about 60,000 km in length.
There are two processes involved in this, one is ridge-push and the other is slab-pull, they are responsible for the spreading seen at the mid-ocean ridges, while there is some uncertainty about the fact which is dominant.
Mid Atlantic Ridge
The Mid-Atlantic Ridge abbreviated as MAR is the mid-oceanic ridge which is divergent or is constructive with a plate boundary that is located along the Atlantic Ocean floor. Also, this serves to be the longest mountain range in the world. The Mid-Atlantic Ridge separates North America from the Eurasian and African Plate; this happens in the North Atlantic. Also, this ridge separates North America from Azores Triple Junction. While, in the South of Atlantic, the ridge separates the African and the South American plates. The ridge further extends from a place in the Gakkel Ridge which is called the Mid-Arctic Ridge to the northeast in Greenland, proceeding southward to Bouvet Triple Junction in the Southern part of the Atlantic.
We know that the Mid-Atlantic Ridge is majorly an underwater feature, while portions of it have elevation to the extent above the sea level, for example in Iceland.
Submarine Ridge
Submarine Ridge is quite elongated and steep-sided elevation of the ocean and the sea floors. The Submarine ridges extend up to hundreds and thousands of kilometers, lengthwise and the width is about several hundred km. Here the peaks often rise above sea level to form many such islands.
In the submarine continental margins, the submarine ridges are very rare, while their structure being analogous to the structure of those of the mountains which are located on the adjacent parts of these continents. In the transition zone, the submarine ridges appear mainly like the island arcs.
On the ocean floor, the submarine ridges may be block, or block-folding, or like the volcanic ridges. The mid-ocean ridges are the largest submarine ridge.
Indian Ocean Ridge
Talking about the Indian Ocean Ridge, the Carlsberg Ridge which is also a submarine ridge of the Arabian Sea and the Indian Ocean is a prominent feature. This ridge is a portion of the Mid-Indian Ridge and this extends from the vicinity of Rodrigues Island to the Gulf of Aden, basically, this means northwest to southeast. This ridge separates the Arabian Sea located in the northeast from the Somali Basin in the southwest.
East Pacific Rise
The East Pacific Rise is also a mid-oceanic ridge which has a divergent tectonic plate with a boundary that is located along the Pacific Ocean floor. This separates the Pacific Plate in the west from the North American Plate, from the Rivera Plate, from the Cocos Plate, the Nazca Plate and also from the Antarctic Plate. This runs southward from the Gulf of California which is in the Salton Sea basin, South California to a point near 55° S, 130° W, then it joins the Pacific-Antarctic ridge.
FAQs on Oceanic Ridge
1. What is an oceanic ridge in simple terms?
An oceanic ridge is essentially a massive underwater mountain range. It is formed by the movement of Earth's tectonic plates on the ocean floor. These ridges are the longest and most extensive mountain chains on the planet, stretching across the globe's oceans.
2. How are mid-ocean ridges formed?
Mid-ocean ridges are formed at divergent plate boundaries, where two tectonic plates are pulling away from each other. As the plates separate, hot magma from the mantle rises to fill the gap. This magma cools and solidifies, creating new oceanic crust and building up the mountain range over millions of years in a process known as seafloor spreading.
3. What are the main parts of an oceanic ridge?
A typical mid-ocean ridge has several key features. The most prominent are:
- The Crest: This is the highest point of the ridge.
- Rift Valley: A deep valley that runs along the center of the crest, which is the primary site of volcanic activity and seafloor spreading.
- Transform Faults: These are cracks or fractures that cut across the ridge, causing it to be offset in segments.
4. Can you give a famous example of an oceanic ridge?
The most well-known example is the Mid-Atlantic Ridge. It runs down the center of the Atlantic Ocean, from the Arctic to the Antarctic, separating the Eurasian and North American plates from the African and South American plates. Iceland is a part of this ridge that has risen above sea level.
5. What is happening at an oceanic ridge?
An oceanic ridge is a site of intense geological activity. The key processes happening are seafloor spreading, where new crust is constantly being created, frequent underwater volcanic eruptions as magma emerges, and numerous small earthquakes caused by the movement of the tectonic plates.
6. How do oceanic ridges provide evidence for the theory of plate tectonics?
Oceanic ridges are one of the strongest pieces of evidence for plate tectonics. Scientists have found that the age of the rocks on the seafloor increases as you move away from the ridge's crest. Furthermore, the pattern of Earth's magnetic polarity recorded in the rocks is symmetrical on both sides of the ridge, confirming that new seafloor is being created at the center and pushing older rock outwards.
7. What is the main difference between an oceanic ridge and an oceanic trench?
The main difference lies in how they are formed and what they look like. An oceanic ridge is a constructive mountain range formed at a divergent boundary where plates separate. In contrast, an oceanic trench is a very deep, narrow depression in the ocean floor formed at a convergent boundary where one plate sinks beneath another (subduction).
8. If new crust is always forming at oceanic ridges, does this mean the Earth is getting bigger?
That's a great question! The Earth's size remains relatively constant. While new crust is being created at oceanic ridges, old oceanic crust is simultaneously being destroyed or recycled back into the mantle at subduction zones, which are typically found at oceanic trenches. This creates a balanced system of creation and destruction.
