Introduction

The ocean floor or the seabed is the bottom of the sea. It contains minerals like copper, zinc, nickel, gold, silver and phosphorus. The Ocean Relief is mainly caused due to volcanic, tectonic, depositional and erosional methods and their interactions. It is mainly divided into major and minor relief features. The ocean floors cover approximately 70% of the Earth and comprise a complex structure hard to dissect. The ocean floor can be divided into primary and minor features. There are four divisions of the ocean floor’s significant components: Continental Shelf, Continental Slope, Deep Sea Plain, and Oceanic Deeps or Trenches. This article explores the four major divisions of ocean floor mapping features in detail.

OCEAN FLOOR MAPPING: MAJOR FEATURES

Listed below are the four major divisions of Ocean Floor Mapping:

Continental Shelf:

• The continental shelf is the extended margin of continental plates
• Shallow seas and gulfs occupy the continental shelves
• The continental shelf is the shallowest part of the sea
• The end of the continental shelf is a steep slope known as the shelf break
• The depth of these regions approximately ranges from 120 to 400 m
• Some regions may be as shallow as 30 m, while others may be as deep as 600 m
• The approximate width of the shelves is between 70 and 80 km
• The continental shelves cover approximately 7.5% of the oceans
• The gradient of the continental shelf is approximately 1 degree or less
• Coral reefs occur in these regions
• The enormous deposits of sediments of river glaciers cover the continental shelves
• These sediments become fossil fuels gradually over time
• The continental shelves form mainly due to sedimentary deposits of water bodies and glaciers. Other factors can include a rise in sea level and the submergence of a continental part

The types of continental shelves include:

• A glaciated shelf
• Coral reef shelf
• Shelves of a large river
• Shelves with dendritic valleys
• Shelves along with mountain ranges

• Continental shelves generally do not exist in regions where mountains run closer or parallel to the coast. Some examples of this include the Coasts of Chile and the West Coast of Sumatra
• Most of the marine food known as plankton comes from continental shelves since this region is dense and receives sunlight
• Continental shelves also contain rich fishing grounds, economic minerals and Poly metallic nodules that are good sources of iron ores, including manganese, iron, copper, gold etc. 
• These areas are home to most marine life because of less sunlight and fish food availability
• The continental shelves have the most minerals and oils too. As a result, there is a massive availability of petroleum and natural gas

Examples of continental shelves include the Siberian Shelf in the Arctic Ocean. It is the world’s most enormous continental shelf. The Siberian Shelf measures upto 1,500 Km in width.

The Continental Slope

• The continental slope connects the continental shelf and ocean basin
• It commences from the shelf breaks, the steep slopes where the continental shelves abruptly end
• The continental slope areas contain an abundance of trenches and canyons
• The depth of this region ranges from 200 to 3000 m
• The gradient of the continental slope ranges from approximately 2-5 degrees
• The perimeter boundary of the continental slope marks the end of continents
• Continental rise occurs in these areas due to the deposits of sediments that form the base of the continental slopes
• There is no existence of marine life in the continental slope areas

Examples of continental slope regions include The Blake Plateau and the Continental Borderland of Southern California

The Deep Sea Plain

• The Deep Sea plains are gently sloping regions of the ocean basins
• They are the flattest and the smoothest areas on earth because of the marine and shallow-water sediments, preventing irregularity in the geographic regionThe Deep Sea plains cover almost 40% of the ocean floor mapping
• The depth of these regions ranges from 3000 to 6000 m
• The Deep Sea plains contain an abundance of fine-grained sediments like clay and slit
• Living organisms create sediments in these regions. These sediments are called Oozes
• Oozes occur in regions where there is abundant growth of living organisms.
  

  The Oceanic Deeps or Trenches:

• The oceanic deeps are the deepest regions of the oceans
• They are also known as submarine trenches
• The sides of the trenches are steep and include marrow basins
• The oceanic deeps generally occur due to tectonic movements and volcanoes
• The depth of these areas ranges from 3 to 5 kilometres
• Tsunamis and Earthquakes occur majorly in this region
• Ocean deeps or trenches are usually found in tsunami and earthquake-prone areas
• Examples of trenches include the Pacific region trenches, including Mariana Trench, the world’s deepest trench

These are the four divisions of the major features of Ocean floor mapping. They are essential in Geography lessons because it gives a profound insight into the ocean floor and its divisions. 

Conclusion

Understanding about ocean floor mapping and its major features is an important topic to study. It gives a detailed account of the separate parts of the ocean floors. The study of the first part, the continental shelf, is vital because it is probably the most crucial layer of the ocean floor. It is rich in minerals and oils and includes most marine life. There is also abundant plankton in these regions due to abundant sunlight. The second part of the ocean floor mapping, the continental slope, is crucial because it deals with the link between the continental shelf and the ocean basins. Study on the third part, The Deep Sea Plains, is essential due to the study of abyssal plains and oozes. Finally, knowledge on the last part, The Ocean Deeps or Trenches, is necessary because it deals with the movement of the tectonic plates and the occurrence of earthquakes and tsunamis. Therefore, all four parts deal with the importance of ocean floors.