What is a shelf break in geology?
shelf break, submerged offshore edge of a shallow continental shelf, where the seafloor transitions to continental slope. A shelf break is characterized by markedly increased slope gradients toward the deep ocean bottom.
What causes a shelf break?
Shelf-Break Fronts are a process by which stratification of the water column occurs. This stratification normally results in thermoclines, since they occur where a sudden change in water depth causes a constriction of the current flow.
What is the name of the feature that separates the continental shelf from the continental slope?
The Blake Plateau off the southeastern United States and the continental borderland off southern California are examples of continental slopes separated from continental shelves by plateaus of intermediate depth. Slopes off mountainous coastlines and narrow shelves often have outcrops of rock.
What is a shelf slope?
Topography. The shelf usually ends at a point of increasing slope (called the shelf break). The sea floor below the break is the continental slope. The continental slope is much steeper than the shelf; the average angle is 3°, but it can be as low as 1° or as high as 10°. The slope is often cut with submarine canyons.
What are shelf breaks?
Definition of Shelf break: The steepening of the bottom that marks the seaward limit of the continental shelf and the beginning of the continental slope.
Why is the shelf break important?
Exchange of water across the Antarctic shelf break has considerable scientific and societal importance due to its effects on circulation and biology of the region, conversion of water masses as part of the global overturning circulation and basal melt of glacial ice and the consequent effect on sea level rise.
What is the name of the fissures that are cut into the continental slope and shelf?
In many places, the Continental Shelves and Slopes are furrowed by deep V-shaped valleys known as “Submarine Canyons.” Where the shelf is wide, as on the Atlantic Coast of the United States, these canyons begin far out from shore near the outer edge of the shelf.
Where do the continental shelves end?
A continental shelf typically extends from the coast to depths of 100–200 metres (330–660 feet). It is gently inclined seaward at an average slope of about 0.1°. In nearly all instances, it ends at its seaward edge with an abrupt drop called the shelf break.
What is called continental slope?
The continental slope (often referred to simply as “the slope”) is commonly dissected by submarine canyons; faulting, rifting and slumping of large blocks of sediment can form steep escarpments, relatively flat terraces and (under certain conditions) basins perched on the slope.
What are canyons on the ocean floor called?
A deep canyon in the ocean floor is called Trench. The sea bottom plunges into deep under-water canyons known as deep-ocean trenches. A trench may be a form of excavation or depression within the ground that’s typically deeper than it’s wide and slender compared with its length .
What is a deep underwater canyon called?
A steep underwater canyon is called a submarine canyon.
Why are continental shelves underneath the ocean?
Over many millions of years, organic and inorganic materials formed continental shelves. Inorganic material built up as rivers carried sediment—bits of rock, soil, and gravel—to the edges of the continents and into the ocean. These sediments gradually accumulated in layers at the edges of continents.