When we talk about plate tectonics theory, we say that the earth's crust is divided into different tectonic plates. That is, on continental and oceanic platforms that are the basis of all the development of life. The Continental platform it is the limit of the continental crust. That is, it is said to the entire surface of the underwater bottom that extends from the coast until there is a jump of less than 200 meters. This area has a great abundance of animal and plant life, which is why it has great economic value for the territories.
In this article we are going to explain everything you need to know about the continental shelf and its importance.
Definition of continental shelf
One thing is that, geologically speaking, let's say that it is one more part of the tectonic plate in which we find ourselves. The difference is that it is underwater and these conditions they make it possible to house a large number of living beings. These living beings constitute what we call biodiversity. The development of underwater fauna and flora increases the resources available to humans. To learn more about how these ecosystems are formed, you can consult our article on the continents and their diversity.
With all this, mineral and rock exploitations are also used. So that, economically, it can be known and defined what the continental shelf is, in 1958 the Geneva Convention made a definition in one of its articles. Under the law, a continental shelf is the underwater platform that surrounds the continental lands to an average depth of 200 meters, which given the low slope reaches an average width of around 90 kilometers.
The outer edge of this platform must have a sharp change in slope to mark its end. At the bottom of this change, we find the ocean floor, which no longer has the same economic value. What we must mention is that these events have caused headaches for governments. The line where the relief changes is called the continental slope. To delve deeper into this phenomenon, you can review the article on continental drift and its impact.
The constitutional law modified the definition previously cited in 1982. Here it was said that the continental shelf of a state comprises from the bed and the subsoil of the submarine lands that are beyond its territorial sea and along the extension natural of its territory to the outer edge of the continental margin, or up to a distance of 200 nautical miles from the beginning of the territorial sea.
Parts of the continental shelf
These new definitions provided the necessary concepts so that there were no mistakes when exploiting the present natural resources. With all this, the continental shelf can be perfectly divided into two parts: the continental margin and the continental slope.
Continental margin
This first part is the one that is covered in all the extension that is submerged in the land of the continent. It is mainly composed of the bed and subsoil of the underwater zone, the slope and the continental rise zone. However, this entire part does not encompass the deepest ocean beyond where we are 200 meters deep. The platform is delimited in the most extreme and remote areas by a distance that it does not usually exceed 350 nautical miles from the sea line.
The entire area where the natural resources targeted for exploitation and economic development are located is submerged underwater. Here, marine life is vast and varied, so most fishing takes place here. Traveling to the high seas to fish is more expensive, less efficient, and more dangerous. Therefore, the economic rate of return is important when we talk about the profitability of products. To see how these ecosystems affect the regions, you can read our article on the world's seas and their importance.
Not only do we find valuable resources such as flora and fauna, but we also have areas where a quarter of all the world's oil and gas reserves are found. Thus, It is not uncommon to see oil rigs doing their thing in areas of the continental shelf. The problem with this is the impacts that this oil extraction causes on marine life. There are many species that are threatened by the noise of the oil companies, the contamination of the water, fragmentation and deterioration of habitats, etc. Normally, what offers economy destroys nature.
Continental slope
This other part of the continental shelf It is the underwater region that is located between 200 meters deep and 4000 meters under the sea. On the slope we can find important changes in the entire morphology of the terrain and relief. The most normal thing is to observe valleys, seamounts and huge canyons within the ocean. Landslides can also be seen on the western slopes, as they have been created by the accumulation of numerous sediments deposited by rivers from nearby lands. To better understand underwater geography, it is useful to know the Pacific Ocean and its geography.
Animal and plant life in this area is more difficult. Biomass decreases because the depth at which they are found prevents sunlight from reaching them and allowing them to proliferate. Throughout this area of the continental slope, the ocean floor extends to a depth of 4000 meters. Here, the average slope is usually between 5 and 7 degrees. although in some areas it can reach 25 degrees and even exceed 50 degrees.
In terms of surface, we can find surfaces between 8 and 10 km long and up to 270 km.
Economic importance
It is no wonder that governments have fought hard for who can exploit these areas and benefit economically from their resources. Between the abundance of marine vegetation used in cosmetics, pharmaceuticals, medicine, etc., the fauna used in restaurants, food preparation, captive breeding, fish tanks, fishing, etc., and energy resources such as oil and natural gas reserves, we find ourselves with a very rich platform of resources of all kinds. If you'd like to learn more about the wealth of marine resources, check out our article on How islands are formed and their relationship with marine resources.
As you can see, the continental shelf is more important than it may seem from its name and I hope that with this information you can learn more about it.