Continental Rise

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Continental Rise Definition

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Continental Rise meaning will seem to be very simple once you go through the given definition. There's a surprising place where possibly half of the world's sediments are settling. These materials that collapse by eroding and then transported by rivers and streams aren't always ending up in stream beds, river deltas or flood zones. Rather, many of them finish up in a place that's not on land at all. These sediments are sent to the continental rise below the ocean, where enough of them settle that it induces a distinctive mound that encompasses the world's continental edges.

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Continental Margin

Beginning from the continental edge, where dry land turns to ocean, the first of three parts of the region known as the continental margin, is the shallow, gentle descent of the continental shelf. This area can be as tapered as 15 miles and as wide as 228 miles.

Think of it as an elongated hill of sediments deep beneath the ocean's surface. The continental rise is also part of a bigger region known as the continental margin.

After the continental shelf, you would be in for a trace of a fall. Next is the steep cliff of the continental slope. The transformation between the continental shelf and the continental slope is what we call the continental shelf break. It's not really an exact spot, but more like a region where the continental margin moves from the less steep continental shelf to the much steeper continental slope. The continental slope is nowhere near to smooth and rather, is marked by innumerable, submarine canyons that run perpendicular to the continental slope.

Ultimately, after the continental slope, you would get access to the third part of the continental margin. While it's greater level than the continental slope, it's not as very smooth as what follows – the expansive ocean floor.

Difference Between Continental Slope and Continental Rise

Continental slope is a slope with a steep or gentle gradient. It is a sectional division after the continental shelf. On the other hand, Continental rise is simply the deposition of debris or sediments brought by the currents.

Animals that Live in the Continental Rise

Talking about the continental rise marine life, we can find animals like Crab, cod, tuna, lobster, sole, halibut, mackerel and Dungeness in the continental rise depth. Permanent rock fixtures are home to anemones, clams, corals, mussels, oysters, scallops, and sponges. Huge sea animals such as whales and sea turtles can be found in continental shelf areas as they follow migration routes.

The Geologic Basis For the Continental Rise

The concept of the continental rise appeared across the classic passive margin area of the western North Atlantic. There the continental rise envelops the ocean crust fringing the fractured and the faulted continental margin. It is the location where the sediment discards from the continent into the deep sea deposits. Along active margins where ocean crust is being subducted under the continental crust, the margin is often manifested by an ocean trench; there is no continental rise. However in some regions where there is a massive thickness of sediment on the ocean floor making way to the subduction zone, or where the supply of sediment from the continent into the subduction zone totally brims up the trench, a narrow continental rise may occur.

Fun Facts

  • The continental rise is the gently disposed slope between the substructure of the continental slope and the deep ocean floor.

  • The expression “continental rise” was initially used by Maurice Ewing and Bruce Heezen in their narrative of the effects of the 1929 Grand Banks earthquake.

  • It was formally described by Heezen et al. in GSA Special Paper 65 in 1959.

  • “Since the continental slope is restricted to gradients higher than 1:40, the lower portion of the continental margin is split into a separate province, the continental rise”.

  • In many regions, domestic morphologic characteristics interfere with the usual slopes such that neither the upper or lower limits of the continental rise are well described.

FAQ (Frequently Asked Questions)

1. What Controls the Continental Rise?

Answer: Following are the factors responsible to control the continental rise depth:

1. Nature of the Crust

Where the continents have shattered, in the Atlantic, Indian, and Arctic oceans, the continental rise envelopes the oldest ocean crust overriding it. Given that the ocean crust subsides with age, this is an area where the differences in elevation between continental and oceanic crust are at the maximum.

2. Detrital Sediment Supply

The continental rise is the ultimate site of accumulation of sediment weathered off the continents. The current rate of detrital sediment weathered from land and carried to the sea is approximately about 24! 1012kg / year. However, the continental shelves are only able to lodge about 10 % of this load at high sea level stands and nearly none at sea level low stands.

2. How Continental Rises are Formed?

Answer: There are a number of ways in which all those sediments end up at the continental rise. A huge amount of sediments get across the submarine canyons and consolidate together in mounds to form parts of the rise. However, sediments also come through there from rivers and streams on land that flow to the ocean. The river and stream water is laden with sediment which finally settles out in the ocean. Since the continental slope is steep, it's more complicated for them to settle there, thus the sediment gathers at the continental rise instead.