5.5: Continental Rise

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Miracosta Oceanography 101
Miracosta)

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Continental Rise

A continental rise is a wide, gentle incline from a deep ocean plain (abyssal plain) to a continental slope.

A continental rise consists mainly of silts, mud, and sand, deposited by turbidity flows, and can extend for several hundreds of miles away from continental margins. Although it usually has a smooth surface, it is sometimes crosscut by submarine canyons extending seaward of continental slope regions.

The continental rise is generally absent in regions where deep-sea trenches exist where subduction zones are active.

Continental rises feature deep-sea fans. In appearance they are much like alluvial fans on land found along the fronts of mountain ranges. Deep-sea fans are accumulations of sediment deposited by turbidity currents (called turbidites) at the foot of the continental slope. Turbidites are underwater landslide deposits. Over time they build up the large deep-sea fans that coalesce to form the continental rise along some continental margins.

Figure 5.6. Bathymetry of the Monterey Bay offshore region highlights the character of the continental slope and rise.