What is the Continental Rise?

The continental rise is an underwater feature found between the continental slope and the abyssal plain. This feature can be found all around the world, and it represents the final stage in the boundary between continents and the deepest part of the ocean. The environment in the continental rise is quite unique, and many oceanographers study it extensively in the hopes of learning more about the ocean and geologic history.

Before delving into specifics, it can help to have a quick overview of the major features of the ocean floor, starting with the continental shelf, a relatively shallow area of water which forms a transition between the elevated land of the continents and the open ocean. At a certain depth, the continental shelf begins to drop sharply, forming a feature called the continental slope. Unlike the continental shelf, the continental slope is rather steep, and geologists suspect that it may mark an earlier sea level in Earth's history.

At the bottom of the continental slope, one will find the continental rise, an underwater hill composed of tons of accumulated sediments. Beyond this stretches the abyssal plain, an extremely flat area of the sea floor which is also incredibly deep. The abyssal plain hosts many unique life forms which are uniquely adapted to survival in its cold, high pressure, and dark conditions. The flatness of the abyssal plain is interrupted by massive underwater mountain chains near the tectonic boundaries of the Earth's plates.

The formation of the continental rise is a constant and very slow process. As rivers and streams travel over land, they pick up sediment, silt, and an assortment of other material, which is gradually carried out to sea. Some of these sediments settle on the continental shelf, but others drift down the continental slope to form the continental rise. The continental rise is often very nutrient rich, because of the sediments that it contains, and it may attract an assortment of undersea creatures looking for snacks.

These sea creatures, in turn, contribute more sediments. Over millennia, the continental rise takes on the shape of a dense wedge of material which has settled at the bottom of the continental slope, much like detritus which piles up at the base of a cliff. The feature is named because it creates a characteristic sudden rise of the ocean floor which is very distinctive on the radar screens used by ships. It alerts ships to the fact that they are approaching the continental shelf, suggesting that land cannot be too far away.