Oceanic floors are also called seabed. The floors of the ocean are divided into four major divisions such as the continental shelf, the continental slope, the deep sea plain, and the oceanic deeps which are discussed in detail below. In this article, we will learn about the Divisions of Oceanic Floors followed by detailed explanations which are useful for the geography syllabus of UPSC IAS Exam.

Oceanic Floor

General Characteristics of Ocean Floor

• The ocean floor shares many of the same properties as terrestrial locations around the world.
• Under the sea's surface, mountains, basins, plateaus, ridges, canyons, and trenches can all be discovered.
• The relief characteristics seen on the ocean floor are referred to as submarine relief
• Many people assumed that the ocean floor was perfectly flat until the invention of SONAR.
• As technology advanced, it became easier to explore the structure, characteristics, and topography of the ocean floors.

Divisions of Oceanic Floors - Concept

• Oceans cover 69 percent of the earth's surface, while continents cover only 29 percent.
• An oceanic basin is the land surface under an ocean that includes the topography under the water.
• Plate tectonics determines the structure of the ocean floors throughout the world.
• There are four major divisions on the ocean floor:
  1. The Continental Margin (Continental Shelf)
  2. The Continental Slope
  3. The Abyssal Plain (Deep Sea Plain)
  4. The Ocean Deeps or Submarine Trenches
• Apart from these divisions, the ocean floors have ridges, hills, seamounts, guyots, trenches, and canyons, among other relief features.

Divisions of Oceanic Floors

The Continental Margin

• A continental margin (or) shelf is a section of a continent that is submerged beneath a shelf sea, which is a relatively shallow body of water.
• During glacial eras, sea level reductions exposed several of these shelves. An insular shelf is a shelf that surrounds an island.
• Between the continental shelf and the abyssal plain, the continental margin consists of a steep continental slope surrounded by a flatter continental rise, where sediment from the continent above cascades down the slope and collects as a pile of sediment at the bottom.
• The continental shelf is the stretch of land between continents that is populated by gulfs and seas that are relatively shallow.
• It is the ocean's shallowest point.
• The shelf generally comes to an end at an extremely steep slope known as the shelf break.
• Continental shelves have an average breadth of 80 kilometers.
• Along some margins, as on the Chilean coasts, continental shelves are very narrow or non-existent.
• The Arctic Ocean's Siberian Shelf is the world's largest one.
• Massive sedimentary deposits, which the continental shelves have accumulated over time, have turned out to be a source of fossil fuels.

Continental Margin

The Continental Slope

• The sloping portion of the continental margin that goes from the continental shelf to the deep sea bottom of the abyssal plain is known as the Continental Slope.
• It reaches a depth of 180 meters to 3600 meters below sea level.
• They have very few sediment deposition due to their steepness and increasing distance from the ground.
• On the shelf, there's also a lot less sea life than there is on the shelf.
• At the bottom of the continental slope, sediments will be deposited. A belt of sedimentary deposits defines the Continental Rise.

Abyssal Plain

• It is an underwater plain on the deep ocean floor, commonly found at depths between 3,000 and 6,000 meters.
• It is also known as Deep Sea Plain.
• Abyssal plains cover more than half of the Earth's surface, lying between the foot of a continental rise and a mid-ocean ridge.
• They are one of the world's flattest, smoothest, and least explored places.
• Abyssal plains are important geologic features in ocean basins (the other elements being an elevated mid-ocean ridge and flanking abyssal hills).
• The abyssal plain was formed by the spreading of the seafloor (plate tectonics) and the melting of the lower oceanic crust.
• The deep-sea plain is characterized by gently sloping sections.
• These are the flattest and flattest places on the planet.
• Fine-grained sediments such as silt and clay cover the plains entirely.

Abyssal Plain

The Ocean Deeps or Submarine Trenches

• The ocean deeps are the deepest part of the ocean. Submarine trenches are another name for them.
• These trenches aren't always found in the ocean basin's center. They could be quite close to, or even parallel to, the continents separated by the Fold Mountains.
• The Pacific Ocean has the greatest number of trenches.
• The Mariana Trench is the world's deepest known site, located in the Pacific Ocean.
• They're typically located around volcanic and earthquake-prone areas. Massive earthquakes and tsunamis are the result of them.

Significance

• Ocean exploration data can help us better understand how we affect and are affected by changes in the Earth's ecosystem, such as weather and climate.
• Ocean exploration can provide new insights on earthquakes, tsunamis, and other natural disasters, allowing us to better understand and respond to them.

Conclusion

The entire ocean is overflowing with undiscovered organisms and treasures in vast under-explored places. Our knowledge of the ocean and its role in maintaining the balance of Earth's systems remains limited, even as our dependence on healthy, functioning marine ecosystems grows.