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Why are continental shelves along the Atlantic Ocean often broad and covered by thick sediment?

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continental shelf The broad, gentle pitch of the continental shelf gives way to the relatively steep continental slope. The more gradual transition to the abyssal plain is a sediment-filled region called the continental rise. The continental shelf, slope, and rise are collectively called the continental margin.

Continental shelves along the Atlantic Ocean are typically broad and covered with thick sediment because they are situated on passive continental margins. Unlike active margins, which are characterized by tectonic deformation and steep, narrow shelves, Atlantic margins are the remnants of the trailing edges of massive plates that split apart millions of years ago.12

As these plate edges gradually contracted and subsided, they created stable environments that allowed for the long-term accumulation of sedimentary material. Over millions of years, large quantities of sand, silt, and mud transported from the continents settled along these seaward sides. Because these margins lack the tectonic deformation found at subduction zones, they have maintained a relatively level, broad profile that effectively traps and preserves thick layers of sediment.13