Over the Edge: Continental Margins
The continental margin is the submerged outer edge of a continent. Comprised of granitic crust, the continental margin includes the continental shelf and continental slope.
Over the Edge: Oceanic Ridge System, The
Perhaps the most striking feature that characterizes the deep ocean floor is the vast oceanic ridge system that encircles the Earth along tectonic plate boundaries.
Over the Edge: Deep Ocean Floor, The
Although it comprises more than half of Earth's surface area, the deep ocean floor was a region of near total mystery until fairly recently. Even now, efforts to map ocean basins are in their infancy.
Over the Edge: Undersea Volcanic and Tectonic Activity
For large stretches the deep ocean basin is flat. But seamounts, guyots, island arcs and trenches, all of which result at least in part from tectonic activity, break up the sameness.
Over the Edge: Submarine Canyons
A submarine canyon is a steep, V-shaped valley that cuts across the edge of the continental shelf and slope. It acts as a funnel, carrying sediment down to the abyssal plain.