OCEAN RIDGES: CHARACTERISTICS, HOW THEY ARE FORMED, EXAMPLES - ENVIRONMENT - 2025

The ocean ridges correspond to the system of underwater mountain chains that, within each of the oceans where they are located, draw the limits of the different tectonic plates that make up our planet.

Contrary to what one might think (and based on the most popular theory), these mountain formations are not generated by the collision of the plates; On the contrary, they are generated by the volcanic material (lava) that is constantly expelled by multiple fissures in the extension of the chain as an effect of the separation of the tectonic plates.

The ocean ridges make evident the limits of the tectonic plates. Source: YSiSoyMejorQueTu

The volcanic activity in the oceanic ridges is intense; Such is the level of lava expulsion to the surface that these formations can measure between 2000 and 3000 m in height. It is a considerable height if we take into account that it is only lava piled up at great depth and that the highest peak above sea level, Everest, is just over 8800 m.

From the identification of the thickness of the sediments of these extensive underwater mountain ranges - which together reach some 60,000 km - arises the theory that states that the continents are born of progressive and constant accumulations of material that emerged from these chains and that with the passage of time was folding, cooling and consolidating.

An interesting and curious piece of information is the one thrown by the study of certain minerals contained in the magmatic flows emanating from these ridges, which are aligned in precise ways according to their location on the planet.

This made scientists embark on the study of the forces that determine this phenomenon, thus discovering the electromagnetism of the planet, the only phenomenon that could explain the initial question.

characteristics

Worldwide distribution of ocean ridges.

Like any system of mountains on the earth's surface, in their development throughout the planet the oceanic ridges have generated a topography that varies between 2000 and 3000 m in height.

They have a really rugged profile, with deep valleys, slopes and ridges that can eventually reach the surface to create new volcanic islands or a set of these.

The most conspicuous feature is a large sunken fringe that the crown along its entire length. This indentation is known as a rift. The rift is a kind of terrestrial "seam" in permanent volcanic activity; It is the site responsible for the lava from the center of the planet reaching the upper crust and gradually accumulating, stabilizing and cooling.

The volcanic activity in the ridges manifests itself in different ways. Although rifts are that strip of unstoppable activity, they are not the places with the most violent activity.

Fumaroles and underwater volcanoes spread by the thousands throughout the 60,000 km of ridges that run through our world. The minerals, which participate in this exchange, are those that sustain life in its most basic form.

Studies on the substance that make up the continents and ocean ridges have determined that in the former the material is much older than that found on the slopes of the ridges. In turn, the material that has been studied in the center of the lats is newer compared to that studied in the outer sides.

All this indicates that the ocean floor is in constant renewal, caused by the continuous flow of magmatic material that accumulates and moves over time, managing to create entire masses of soil above sea level of mineral wealth known to all.

How are they formed?

There are a couple of theories that try to explain the appearance of these underwater mountain ranges. For years, geologists around the world have debated what processes plate tectonics must undergo to create ridges, or what processes these ridges trigger to make tectonic plates move as they do.

The first argument indicates that the phenomenon of subduction is the generator of the ridges. This theory explains that, in their unstoppable advance, tectonic plates often encounter other plates of less density and weight. In this encounter, the densest plate manages to slide under the one with less density.

In its advance, the denser plate drags the other by its weight, breaking it and allowing volcanic material to come off the friction edge. This is how the rift appears, and with it the emissions of lava and basalt also arise.

The following theory defends the creation of ocean ridges with the reverse process, which is none other than the separation of tectonic plates.

This process creates an area where the earth's crust bulges because the material in it stops being firm (due to the separation of the plates itself). This area tends to break down, giving way to the rift and the characteristic eruptive activity of the area.

Difference with oceanic trench

By definition, a pit is a concave area that can be generated by the action of various factors. In this particular case, the oceanic trench has its origin in a process of subduction of the tectonic plates; that is, when two tectonic plates collide, they interact with each other and the one with the highest density slides under the first.

This process of subduction of plates generates in its path areas of different depths and reliefs, the deepest being authentic underwater trenches that, like the one in Las Marianas, can reach 11,000 m in depth.

The most immediate difference is none other than the profile of the relief of each of the cases: while the trench sinks towards the center of the Earth, the ridge tries to emerge from the bottom, successfully on certain occasions, creating volcanic islands.

Temperature and life forms

The prevailing temperature in each of these oceanic features can be taken as another difference: while measurements of the average temperature of the trenches are around 4 ⁰C, the temperature in the ridges is much higher thanks to the incessant volcanic activity.

Another point of comparison is the forms of life of both habitats. In the pits they are rare and complex, they are specialized individuals, adapted to life under crushing pressures and very low temperatures, equipped with mechanisms to hunt and perceive prey without the need for the use of eyes, which are often non-existent.

On the other hand, in the ridges the inexhaustible and permanent volcanic activity means that the individuals who live there are of very low biological complexity, adapted in this case to survive from the transformation of minerals from volcanic emissions into energy. These organisms are considered the foundation of the entire ocean food chain.

Volcanic activity is particularly different in both environments: while the trenches are calm places with zero volcanic activity, the ridges are a hotbed of lava and emissions from the center of the Earth.

Examples of ocean ridges

These vast expanses of seamounts span the entire globe. From pole to pole and from east to west, they can be easily identified. Below is a list of the main ocean ridges, ordered according to the continent to which they belong:

North America

Gakkel bib

It is located in the extreme north of the planet, in the Arctic, and divides the North American and Eurasian plates. It extends for about 1800 km.

Explorer's bib

It is located near Vancouver, Canada. It is the one that is more to the north of the axis of the Pacific Ocean.

Juan de Fuca bib

Located below and to the east of the previous one, between British Columbia and the state of Washington, in the United States.

Fat woman's bib

It is following the anterior ridge and to the south, off the coast of California.

South America

Antarctic-American ridge

It is located in the south of the continent. It begins at the so-called Bouvet Point in the South Atlantic and develops towards the southwest, until it reaches the Sandwich Islands.

Eastern Pacific Ridge

Of approximately 9000 km, it extends from the Ross Sea in Antarctica and, heading north, reaches the Gulf of California. Other secondary ridges are born from this.

Nazca Ridge

It is located off the coast of Peru.

Chile bib

It is off the coast of that country.

Galapagos Ridge

It is located near the islands from which it takes its name.

Scotia bib

It is located in the south of the continent and is considered the underwater portion of the Andes mountain range. It appears as a great arc that is between the Atlantic and the Antarctic.

Africa and Asia

-Antarctic-Pacific Ridge.

-Western, central and eastern Indian ridges.

-Aden Ridge, located between Somalia and the Arab peninsula.

Between America and Europe

-North and south Atlantic ridges.

Europe

Knipovich dorsal

It is located between Greenland and Svalbard Island.

Mohns Ridge

It runs between the island of Svalbard and Iceland.

Kolbeinsey Ridge

It is located in the north of Iceland.

Reikjanes Dorsal

It can be found in southern Iceland.

References

1. "Ocean Dorsals" in EcuRed. Retrieved on March 18, 2019 from EcuRed: ecured.com
2. “Mid-ocean ridges” in Wikipedia. Retrieved on March 18, 2019 from Wikipedia: es.wikipedia.org
3. "Ocean Downs" at the Higher Institute of Geological Correlation. Retrieved on March 18, 2019 from the Instituto Superior de Correlación Geológica: insugeo.org.ar
4. "Oceanic Ridge" in Encyclopedia Britannica. Retrieved on March 18, 2019 from Encyclopaedia Britannica: britannica.com
5. "Divergent edges, anatomy of an oceanic ridge" in Geological Route. Retrieved on March 18, 2019 from Ruta geológica: rutageologica.cl