Biology Forums - Study Force

The thickness of pelagic sediments is highly variable. When averaged, sediments
cover the Atlantic Ocean bottom to a thickness of about 1 kilometer (3,300 feet), and
the Pacific floor has an average sediment thickness of less than 0.5 kilometer (1,650
feet). There are two reasons for this difference. First, the Atlantic Ocean is fed by a
greater number of rivers laden with sediment than the Pacific, but the Atlantic is
smaller in area; thus, it gets more sediment for its size than the Pacific. Second, in the
Pacific Ocean many oceanic trenches trap sediments moving toward basin centers.
Beyond this, the composition and thickness of pelagic sediments also vary with
location, being thickest on the abyssal plains and thinnest (or absent) on the oceanic
ridges.