What is Continental Shelf?
A continental shelf is the continent feature that is submerged under an area of relatively shallow water this is known as the shelf sea. The shelves are greatly exposed by the drops in the sea level during the glacial periods. The shelf which is being surrounded by an island is known as the insular shelf.
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The margin which is located along the continent is situated between the continental shelf and the abyssal plain comprises a steep shaped continental slope which is surrounded by the continental rise, here the sediment from the continent which is above the cascades and down the slope has accumulated a pile of sediment which is at the base of the slope. This extends as far as 500 km (that is 310 mi) from the slope, this consists of the thick sediments which are deposited by the turbidity currents that are originated from the shelf and slope.
Continental Zone
Continental shelf or the zone is a broad type, relatively shallow submarine terrace which is made up of continental crust this is formed at the edge of a continental landmass. The geological feature of the continental shelves is very much similar to that of the exposed portion of the continent which is located adjacent to it. Most of the shelves have a gentle rolling topographic feature which is called a ridge. The Continental shelves consist of about 8 percent of the entire area which is covered by oceanic landforms.
Structure of Continental Zone
A continental shelf extends from the coastal area to the depths of around 100–200 meters (that is approximately 330–660 feet). They are gently inclined towards the sea at an average slope of approximately 0.1°. In all such instances, the shelf ends towards the sea’s edge with an abrupt drop which is called the shelf break. Below here lies the continental slope which has a steeper zone that merges with the oceanic floor and this is called the continental rise. Here the depth is roughly 4,000 to 5,000 meters (which is moreover 13,000 to 16,500 calculated in feet).
Few continental margins like that of the Mediterranean coast of France and at the Porcupine Bank, off the western coast of Ireland, do not have a sharp definition of the slope but rather they maintain a generally convex shape structure towards the seafloor.
Widest Continental Shelf
The widest continental shelf on the planet extends to about 1,210 km (in miles it is 750 miles) it is located off the coast of Siberia, Russia, and into the Arctic Ocean. The Continental shelves serve as an extension of the coastal plains. They are marked by the wide-sloping submerged plains which are approximately 7.4% of the world's oceanic surface that sits above the continental shelves; they have a global average width of approximately 78 km (that is 48 miles).
The average width of the continental shelf is 65 km (that is 40 miles). Most of the continental shelves are very broad, gently sloping plains which are covered by relatively shallow type water. The water depth which is over the continental shelves is the average that are about 60 meters (which is 200 feet).
Continental Shelf Depth
A Continental Shelf Depth is about 60 meters. The average width of the continental shelf is around 65 km (that is 40 miles). Most of the continental shelves are very broad and are the gently sloping plains that are covered by relatively shallow water. The water depth is up to 60 meters (200 feet).
200 meters deep is the Continental Shelf of Australia.
This shelf is very shallow, which is up to 200 meters deep, much compared to the thousands of meters deep in the ocean, it extends outward to the continental slope which is quite deeper where the ocean begins.
100m is the continental margin. This is in the Atlantic Ocean, where the continental margins have a shelf that is broad and flat. This reaches a depth of 100 m. Here the slope is the steep transitional area that is between the shelf and the rise, and this lies between the depths of 100 and 2,500 m.
Continental Platform
In geological meaning, a continental platform is an area that is covered by relatively flat or by gently tilted sedimentary strata. This is an overlie basement that has consolidated igneous or metamorphic rocks which are formed by an earlier deformation. The Platforms, the shield, and the basement rock together make up the cratons.
Continental Sea
The Shelf seas or the continental sea refers to the ocean waters which are located on the continental shelf. Their wave motion is controlled by the summation influence of the tides, wind-forcing, and the brackish water which are formed from the river inflows. The regions are biologically highly productive, this is due to the mixing which is caused by the shallower waters and the enhanced current speeds. Despite all covering, only about 8% of the Earth's ocean surface area, that is the shelf seas supports 15-20% of global primary productivity.
Continental Shelf Location
The Continental Shelf is located at the edge of a continent that lies under an ocean. Here the continents are the main divisions of the land on this Earth. The continental shelf which extends from the coastline of a continent to a drop-off point is called the shelf break. From this break, the shelf descends to the deep ocean floor which is called the continental slope.
Continental Plain
Continental Plain or the continental margin landform is the broad and gentle pitch of the continental shelf that gives way to the steeper continental slope. Gradual the transition more is the abyssal plain. Here the region is sediment-filled and is called the continental rise. The continental shelf, slope, and rise are collectively known as the continental margin.
FAQs on Continental Shelf
1. What is a continental shelf in simple terms?
A continental shelf is the area of the seabed around a large landmass where the sea is relatively shallow compared to the open ocean. Think of it as the submerged edge of a continent that extends from the coastline to a point of steeper descent, known as the shelf break.
2. What are the main features of a continental shelf?
The key features of a continental shelf include:
- Gentle Slope: It has a very gradual slope, typically less than 1 degree.
- Shallow Water: The depth is usually less than 200 metres, allowing sunlight to penetrate and support marine life.
- Variable Width: Its width can range from very narrow to over 1,500 kilometres, like the Siberian Shelf in the Arctic Ocean.
- Sediment Cover: It is typically covered with thick layers of sediment washed off from the land by rivers.
3. How is a continental shelf formed?
A continental shelf is primarily formed by two processes over millions of years. First, during ice ages, a lot of the world's water was frozen in glaciers, causing sea levels to drop. When the ice ages ended, glaciers melted and the rising sea levels flooded the low-lying edges of the continents. Second, rivers continuously carry and deposit vast amounts of sand, silt, and clay onto these submerged areas, building them up over time.
4. Why is the continental shelf so important economically?
The continental shelf is incredibly important for several reasons:
- Rich Fishing Grounds: The shallow, sunlit waters are full of nutrients, making them home to about 90% of the world's most productive fisheries.
- Fossil Fuels: Thick sediment layers on the shelf are ideal for the formation of oil and natural gas, making it a major source of the world's petroleum reserves.
- Mineral Resources: It contains valuable mineral deposits, including sand and gravel for construction, as well as diamonds and gold in some areas.
5. What is the difference between a continental shelf and a continental slope?
The main difference is the gradient or steepness. The continental shelf is the nearly flat, submerged plain extending from the coast. The continental slope is the steep drop-off that begins at the edge of the shelf, marking the true boundary of the continent and its transition to the deep ocean floor.
6. Can you give some examples of major continental shelves?
Certainly. Some of the world's most significant continental shelves include the Siberian Shelf in the Arctic Ocean, which is the largest in the world. Other well-known examples are the Sunda Shelf in Southeast Asia, connecting islands like Borneo and Sumatra, and the Grand Banks of Newfoundland in the Atlantic, famous for its fisheries.
7. How does international law relate to the continental shelf?
In international law, specifically the UN Convention on the Law of the Sea (UNCLOS), a coastal nation has sovereign rights over its continental shelf. This means the country has the exclusive right to explore and exploit the natural resources found on and under its shelf, such as oil, gas, and minerals. This is crucial for a country's economy and territorial control, preventing other nations from accessing these resources without permission.
