North Slope, Alaska: see Alaska North Slope.

Arctic North Slope or Arctic Slope, Alaska: see Alaska North Slope.

Alaska North Slope or Arctic North Slope, region, N Alaska, sloping from the Brooks Range N to the Arctic Ocean. In 1968 large petroleum reserves were found in the Prudhoe Bay area. In 1977 the 800-mi (1,287 km) Trans-Alaska pipeline was completed to carry oil S to the port of Valdez, on the Pacific. Proposals for oil and gas exploration in the Arctic National Wildlife Refuge, E of Prudhoe Bay, have brought continuing controversy. A 2003 National Research Council report on drilling concluded that lasting environmental damage had resulted because the harsh climate slows natural recovery and because there is little incentive to restore areas where drilling has ceased.

Seaward border of a continental shelf. The world's combined continental slope is about 200,000 mi (300,000 km) long and descends at an average angle of about 4° from the edge of the continental shelf to the beginning of the ocean basins at depths of 330–10,500 ft (100–3,200 m). The slope is most gradual off stable coasts without major rivers and is steepest off coasts with young mountain ranges and narrow continental shelves. Slopes off mountainous coastlines and narrow shelves commonly have outcrops of rock. The dominant sediments of continental slopes are muds; there are smaller amounts of sediments of sand or gravel.

Learn more about continental slope with a free trial on Britannica.com.