• What is the oceanic relief?
• Characteristics of the oceanic relief
• Forms of the oceanic relief
• Continental relief

We explain what the oceanic relief is, its characteristics and what its shapes are like. Also, what is the continental relief.

The oceanic relief encompasses all the forms that the seabed acquires.

What is the oceanic relief?

In geography, there is talk of relief oceanic or submerged relief to refer to the different forms that the submarine bed acquires, that is, the portion of the lithosphere or Earth crust that is covered by the seas Y oceans. In simpler terms, we are talking about the shapes that the seabed takes.

In this it differs from the emerged or continental relief, which deals with the portion of land emerging from the waters, and which in the current geographical configuration of our planet, is the minority. The submerged portion of the lithosphere occupies about 70% of the total surface of the planet, and being isolated by the waters of the factors erosive like wind or rain, it is much less varied in relief than its continental version.

This does not mean that the geological configuration of the seabed is static or immobile, far from it. Like the continental relief, it is in continuous change throughout a very slow process over the centuries, known as the geological cycle, whose manifestations are very difficult to perceive throughout human life.

Characteristics of the oceanic relief

In general, the underwater relief is characterized by the following:

• It is, as we have said, the portion of the lithosphere that is submerged under the water of the oceans: the seabed. Therefore, it reaches important depths in specific regions: it extends from 0 to 11 km below sea level.
• They have different margins of volcanic activity, which release terrestrial materials and modify the underwater soil, sometimes giving rise to islands volcanic. Otherwise, they are subjected to erosive forces much more benign than on the surface, so that their changes depend mainly on seismic and tectonic activity.
• It is distributed along the different layers of oceanic water, which vary in conditions of Pressure, luminosity and presence of life, and which are the bathyal zone, the pelagic zone and the abyssal or abyssopelagic zone.
• The oceanic relief tends to be flatter where sedimentation is strong, as a consequence of the sedimentary contribution of rivers, the decomposition of marine fauna and flora, the erosive action of salt water on the seabed itself, or the contribution of underwater volcanic matter. .

Forms of the oceanic relief

Each of the oceanic landforms has its own characteristics.

Although the oceanic relief tends to be much more uniform and homogeneous than its emerged counterpart, it presents common and recognizable shapes, such as the following:

• The Continental platform. Intermediate area between continent and the ocean, the extension of the first within the second is considered, along the coastline to a depth of no more than 200 meters. It has a variable amplitude, starting from the coast, but it is usually an area with a significant presence of sediments and abundant animal and plant life, which is why it tends towards the plain.
• The continental slope. It consists of a strong submarine decline that connects the continental shelf with the abyssal plain, and ranges between 200 and 4,000 meters below sea level. It is a more or less irregular fall, with the presence of valleys and underwater canyons, on an inclined plain whose slope usually ranges between 5 ° and 7 °, but can reach 50 °, producing numerous slides of sedimentary material. In it, natural steps or steps are common, and life begins a noticeable decrease with respect to the previous area.
• The abyssal plain. This is the name given to the deep plain at the bottom of the seas and oceans, between 3,000 and 7,000 meters deep, usually located between the continental slope and some oceanic ridge or, conversely, some abyssal trench. This type of relief constitutes 50% of the ocean floor, and they are the main sedimentation areas of the entire planet. Seismic activity is also frequent, giving rise to small volcanic hills or seamounts (guyots). Being a region that receives little sunlight, life is much scarcer and temperatures low.
• The abyssal trenches. Also known as ocean trenches or sea trenches, they are the deepest known depressions on the planet, penetrating from the abyssal plain to 11,000 meters below the sea surface. Sunlight does not penetrate this unknown region of the oceans, whose waters are around 4 ° in temperature and are subjected to crushing pressures. They are usually found in the proximity of the continental borders or volcanic islands, since their origin is clearly tectonic, and contrary to what it seems, they are not free of life, although it is much scarcer and very different with respect to life. Of the surface.
• The ocean ridges. Mid-ocean or mid-ocean ridges are underwater elevations located in the mid-ocean region, which can reach heights between 2,000 and 3,000 meters above the abyssal plain. They have a natural fissure at their top, known as rift, where magma is continuously emitted, forming new rocks and possible new volcanoes. For this reason, the rocks around them tend to be younger, and a new seabed tends to be produced, in a continuous process of renewal of the ocean floor.

Continental relief

The continental relief, unlike the oceanic one, corresponds to the emerged portion of the earth's surface, that is, to the portion of the lithosphere that is not submerged under water. Unlike the oceanic relief, which is much more homogeneous, the action of the air, the rain and other erosive factors inherent to the atmosphere (the greatest drought, for example) make the continental relief very diverse in its forms.