Continental Margins a. Atlantic-type is divided into continental shelf , continental slope , and continental rise . The continental shelf is from the shoreline to the shelf break or to where there is an increase in the rate change of the slope. The continental slope is similar to continental mountain ranges. The shelf break is 1 to 5 km above the deep ocean basin, except greater near trenches. The average slope is about 4 degrees.
Pacific slopes are steeper than others.
Side-scan sonar measurements indicate that the western North Atlantic coast is dominated by submarine canyons. Turbidity currents are considered to be the major mechanism in the erosion of submarine canyons. They are sediment-laden water currents that periodically move down the canyon. The deposit at the base of the canyon is known as a deep-sea fan . Evidence for turbidity currents is shown in Fig.