The mid-ocean ridge is an extensive underwater mountain range resulting from the constantly altering tectonic plates, heat, and magma emitted from the earth’s core. This phenomenon has occurred since the earth’s evolution, including its land and water forms. They are formed due to the continuous spread of the oceanic lithosphere, the crust, and the upper mantle at the divergent plate boundaries due to convection currents that lift the ocean floor.
How Do Mid-Ocean Ridges Spread?
The mid-ocean ridges are unique features of the ocean basins. The Mid-Ocean ridges of the world are linked to each other, creating a single mid-oceanic ridge system in the world, part of every ocean and sea. Two processes called the ridge-push, and slab-pull spread the mid-ocean ridges. It is not established which process is more dominant.
The Ridge-push is when the ridge’s weight pushes the tectonic plate away from the ridge towards a subduction zone, where the slab-pull comes into the picture. The latter is the tectonic plate’s weight being pulled below the overlying plate, pulling the remaining plate along.
Mid-ocean ridges are spectacular, varying in forms and shapes. These include volcanic ridges, fault zones or transform faults, rifts, rift valleys, fractures, etc. Stretching 65,000 kilometres or 40,000 miles, it is the longest mountain range on the planet. Abyssal hills and plains enclose these ridges on both ends, sometimes accompanied by normal faults giving rise to oceanic core complexes.
Responsible for 75 % of volcanic activity on the planet
Most volcanism on the planet, including the formation of volcanoes and volcanic eruptions, occurs along the mid-ocean ridge, where the new oceanic crust is born, made of lavas and sediments. Over the years, these mid-ocean ridges might be responsible for a lot of undersea and sea-surface calamities, like tsunamis and earthquakes, but for right now, everything seems to be alright.
Basalt, the most common rock, erupts at the spreading centers along the mid-ocean ridge. Scientists study the mid-ocean ridges to understand how the earth works, its topography, biology, physics, and chemistry.
Hydrothermal vents along mid-ocean ridges
Ocean water continuously flows through hydrothermal circulation through cracks or crests at the mid-ocean ridges. When the downward flowing cold seawater comes into contact with the hot, newly formed crust below the surface, various minerals and metals are transferred to the water. The hot, mineral-rich fluids gush out from the splits forming hydrothermal vents.
When the hot water touches the freezing waters of the ocean floor, the metals precipitate from the solution, forming black clouds or black smokers, erupting from chimneys of erstwhile solidified minerals. Enormous metal is released from these vents, making them one of the world’s richest ore deposits. It also supports ocean creatures living in unfathomable depths, who survive by absorbing the hydrogen sulfide in the hot metal-laden water.
A Diverging Phenomenon
The entire procedure of emission of lava and magma to create mid-ocean ridges is a diverging phenomenon. The new underwater landforms that are formed, instead of converging, digress and take new courses, thus separating the bed of the oceans. There are two types of mid-ocean ridges, slow-spreading, fast-spreading ridges, and Axial ridges.
These tectonic plates causing the mid-ocean ridges are also responsible for splitting the earth’s landmass into various continents. Also, the continuous movement and generation of heat beneath the crust are responsible for creating landmass. And since extensive research has been undertaken to study the complex process of formation of mid-ocean ridges, it has been proved that the uninterrupted operation could further separate the present continents and countries.
This is a slow procedure, and since the earth’s core is never going to be cooled, the procedure cannot be stopped. Prominent examples of mid-ocean ridge formations are along Africa, the Red Sea, and the USA. Mid-ocean ridges have started to alter, and newer ones have begun to form because of the excessive heat.
The Mid-Atlantic Ridge and the East Pacific Rise
These are two well-analyzed mid-ocean ridges on the planet. Around 80 mya, North America was being separated from Europe, which gave rise to the Mid-Atlantic Ridge, measuring 10,000 miles lengthwise. It was found in the 19th century when the first trans-Atlantic cable was laid. Running along the center of the Atlantic Ocean, the Mid-Atlantic Ridge is the slow-spreading type, growing at an annual rate of 2 to 5 centimetres or 10 mm to 150 mm a year.
The East Pacific Rise is situated along the floor of the Pacific Ocean. It is fast spreading, at a rate of 6 to 16 cm a yr. As the process is fast, no valley has been formed in the Pacific. It contains only a volcanic summit, smaller than the Atlantic rift valley. Most of the rise lies over 3200 km from the South American coast and rises around 1800 to 2700 meters above the ocean floor.
The Southwest Indian Ridge and the Gakkel Ridge
Earth is the only planet where life, as we know it, exists. In thousand years of evolution, right from when dinosaurs and other creatures roamed the earth until now, when humans are finding ways to develop and enhance the quality of life, the earth has been helpful with its resources. And just like evolution altered the course of the landform and caused the extinction of the dinosaurs, it is quite possible that in the years to come, evolution could change the geography and topography of the earth. Mid-ocean ridges are just one example of the earth’s evolution process.
Frequently Asked Questions
1. What is the most famous Mid-Ocean Ridge?
The Mid-Atlantic Ridge, located in the Atlantic Ocean, is the most famous Mid-Ocean Ridge, spreading at a rate of 0.8 to 2 inches yearly.
2. What are Mid-Ocean Ridges?
Mid-Ocean Ridges are long, seismically active underwater ridge formations situated amidst the world ocean basin.
3. How are Mid-Ocean Ridges formed?
They occur along the divergent plate boundaries, where a new ocean crust is formed due to the spreading of tectonic plates. As they grow apart, the molten rock beneath the earth’s crust rises to the seafloor through cracks generating significant volcanic eruptions containing lava and basalt.
4. Are Mid-Ocean Ridges Volcanoes?
Mid-Ocean Ridges are underwater volcanoes and mountains encircling the entire ocean and sea floor.
5. What are examples of Mid Ocean-Ridges?
Some examples include- the Mid-Indian Ocean Ridge, Carlsberg Ridge, Pacific-Antarctic Ridge, and the East Pacific Rise.
6. Which country is located at the Mid Ocean ridge?
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Zahra is an alumna of Miranda House, University of Delhi. She is an avid writer, possessing immaculate research and editing skills. Author of several academic papers, she has also worked as a freelance writer, producing many technical, creative and marketing pieces. A true aesthete at heart, she loves books a little more than anything else.