What is meant by continental shelf and continental slope?
A continental shelf extends from the coastline of a continent to a drop-off point called the shelf break. From the break, the shelf descends toward the deep ocean floor in what is called the continental slope. Even though they are underwater, continental shelves are part of the continent.
How do changes in sea level affect the continental shelf?
Changes in sea level have profoundly affected the biodiversity and distribution of marine life on continental shelves. At the peak of the last ice age the area of shallow continental shelf, where benthic photosynthesis is possible, was approximately 80% less than its present extent (Tassinari et al., 1996).
What is continental slope in geography?
Continental slope – The slope is “the deepening sea floor out from the shelf edge to the upper limit of the continental rise, or the point where there is a general decrease in steepness” (IHO, 2008).
Why continental shelf is richest part of the ocean?
Continental shelves only make up about 6% of the ocean’s surface area, but they are biologically one of the richest parts of the ocean; their shallow depth prevents nutrients from sinking out, and their proximity to the coast provides significant nutrient input.
Why is the continental shelf important?
The significance of the continental shelf is that it may contain valuable minerals and shellfish. UNCLOS addresses the issue of jurisdiction over these resources by allocating sovereign rights to the coastal State for exploration and exploitation.
What happens at the continental slope?
Over geologic time, the continental slopes are temporary depositional sites for sediments. During lowstands of sea level, rivers may dump their sedimentary burden directly on them. Sediments build up until the mass becomes unstable and sloughs off to the lower slope and the continental rise.
How steep is the continental shelf?
about 0.1°
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 the continental shelf?
A continental shelf is the edge of a continent that lies under the ocean. Continents are the seven main divisions of land on Earth. A continental shelf extends from the coastline of a continent to a drop-off point called the shelf break.
How is the 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 is a continental shelf break?
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.
Is the continental shelf storm dominated or tide dominated?
Depending on which factor predominates, typical shelves are storm dominated or tide dominated . Where tidal ranges are large (>2 m) and currents are fast (50 to 100 cm/s) asymmetrical sand ribbons or tidal ridges are formed on the continental shelf at oblique angles to strike.
How are tidal ridges formed on the continental shelf?
Where tidal ranges are large (>2 m) and currents are fast (50 to 100 cm/s) asymmetrical sand ribbons or tidal ridges are formed on the continental shelf at oblique angles to strike. At tidal currents of less than 50 cm/s, strike elongate sheets or waves of sand develop (right).
What are the two types of ocean currents that dominate continental shelves?
Thus, continental shelves are dominated by either: (1) storm currents (80% of the worlds shelves); (2) tidal currents (17%); or (3) intruding ocean currents (3%).
What is the continental slope of the continental shelf?
The continental slope between the shelf and deep ocean floor is relatively narrow (10 to 100 km) and slopes downward at an average angle of 4 to 6 deg. Sediments are moved downslope by gravity, disloged from the shelf/slope break by storms or earthquakes. The characteristic sedimentary features include: