Abyssal Plain
After you leave the continental margin and the continents behind, you have reached the deep, dark ocean floor. In many oceans, you will find yourself on an abyssal plain. These are some of the flattest and deepest regions of the Earth and were formed by sediment falling over millions of years. All of this sediment built up to cover whatever features did exist and created a broad, flat plain. Some of these regions are over three miles below the ocean surface. Roll your cursor over the image below to see what is under all that sediment.
View a printable version of this interactivity.
Most of the abyssal plains are found in oceans with a broad continental margin, such as the Atlantic and Indian Oceans. Sediments from the surrounding continents find their way to the bottom of the ocean and settle there along with other materials. In some places, the sediment can be as thick as 3,000 feet. Imagine the amount of sand, silt, and clay it would take to fill that space. The abyssal plain will provide you with a long journey – it is extremely large.
In oceans with active margins, and therefore narrow continental margins, such as the Pacific, sediments from the continents never make it that far into the ocean. Instead, the deep ocean trenches found in these oceans prevent the sediment from traveling much past the continental margin. As a result, the sediment does not build up to form an abyssal plain.
Not all of the abyssal plain is featureless. In some areas there are hills and domes of old volcanic activity. Though they are covered with sediments, some of these abyssal hills can reach elevations of a few hundred to one thousand feet. Overall, the abyssal plain is a flat, deep area, with a few hills, and a lot of sediment.
Humpback Anglerfish
Visit the NOAA website and watch the video Lesson 6 Deep-Sea Benthos. After you watch the video, click the Global Impact tab and watch that short video as well.
As you watch both videos, make sure to take notes about the following items:
- Any adaptations that deep ocean organisms have that enable them to live in these environments.
- List potential benefits that humans may receive by studying the deep ocean creatures
Abyssal Plain Review
Now that you have explored the abyssal plains, review your knowledge of the ocean floor in this non-graded interactivity. Drag and drop the labels to place them in the order in which they appear in the image. Click SUBMIT to check your responses. Click the player button to begin.