The submerged relief is the name given to the elevations of the earth's crust that are below sea level and are in turn covered by seawater. They include all the outstanding slopes that arise at the bottom of seas and oceans and even on the so-called continental shelf.
The submerged relief may or may not be a continuation of the emerged reliefs, which are elevations of the earth's crust originating above sea level.
The submerged relief is below sea level
Types of submerged relief
They are classified into two types according to their origin in the level of underwater relief:
Reliefs of the continental margin
They are considered the submarine continuation of the emerged reliefs. They are all land elevations and any type of eminence that prolongs the reliefs born above sea level.
These reliefs are always within the continental shelf, which is the submarine extension from the beginning of the coast and up to 200 meters deep below sea level.
The length of the continental shelf is variable, since it has qualities of the geography that surrounds it.
In mountainous growths close to the coast, such as inlets, the reach of 200 meters of depth can be abrupt. On the other hand, in the coastal plains the continental shelf can extend for kilometers.
Reliefs of the ocean floor
These are the landforms of the earth's crust found on the seabed, also called oceanic crust.
They start from the continental slope, a steep slope that originates after the continental shelf, whose depth can vary between 200 meters and 3500 meters. The end of the slope begins the abyssal plains, which announce the bottom of the ocean.
Main reliefs of the ocean floor
Oceanic ridges
Also known as mid-ocean ridges, they are underwater mountain ranges that interrupt the plains of the ocean floor and whose elevation can reach up to 3,000 meters in height.
Its extension can reach up to 14,000 km. They are caused by the impact of tectonic plates.
These underwater mountain ranges are traversed longitudinally by rifts, large active volcanic pits through which magma that comes from the fissure between tectonic plates gushes out.
Some mid-ocean ridges extend to the surface of the continents. For example, the territorial extension of Iceland encompasses the beginning of the mid-Atlantic ridge, which divides the bottom of the Atlantic Ocean into two segments.
Seamounts
So called all volcanic mountains, active or not, that originate at the bottom of the ocean and whose extension always remains below sea level.
Unlike the mid-ocean ridges, these volcanic elevations are independent, although they are usually grouped.
The islands, volcanic islands and atolls are born from the bottom of the ocean, but if they reach to be above sea level, so they are not considered as submerged reliefs.
Volcano submarine
Mount that arise from cracks in the ocean surface. Its location usually oscillates between 1000 meters and 2000 meters of depth below sea level.
However, they are capable of expelling material even into the Earth's atmosphere.
Guyot
It is a type of seamount characterized by its conical growth and flat top. At some point they were volcanic islands, but their size was diminished thanks to erosion.
References
- Bharatdwaj, K. (2006). Physical Geography. New Delhi: Discovery Publishing House.
- Litvin, V. (1980). The Morphostructure of the Atlantic Ocean Floor. Dordretch - Boston - Lancaster: Reidel Publishing Company.
- Monroe, J., Wicander, R., & Pozo, M. (2008). Geology. Dynamics and Evolution of the Earth. Madrid: PARANINFO.
- Pinxiang, W., & Berggren, W. (1997). Marine Geology and Palaeoceanography. Utrecht - Tokyo: VSP BV.
- Sinton, J. (1989). Evolution of Mid Ocean Ridges. Washington: American Geophysical Union.