To determine the topography we consider 2 boundaries in the ocean basin.
1. continental margin
2. deep ocean basin
Boundary between continent & ocean basin ,consist of
Continental shelf , continental slope ,continental rise.
Continental shelf :it is the submerged upper part of the continental margin. Close to land & mostly shallow it’s the source of nutrients for ocean plants most biological productivity overlie on this.
Continental slope: are outer edges of the continental block, zone of steeply sloped seafloor lead towards ocean at the base steep disappear then slope becomes gentle again.
Continental rise : it separates the slope from the ocean bottom. this area being divide into upper & lower part.
Deep ocean basin :main feature id abyssal plain.
Abyssal plain :they are flat ,covered with thick deposits of sediments that come from near by land.they are lithogens particles , biogenous particles.
Characters of Abyssal plain:
1. Mid ocean ridges
2. Rift valley
3. Sea mounts
Mid ocean ridges : long underwater mountain ranges, found in Atlantic ocean & continues through Indian & pacific oceans. Steep sided central valley is prominent.
Rift valley : 1 -2 km deep & bordered by ridge mountains .
Sea mountains : thousands of mountains scattered across the ocean .they formed as volcanoes which has been flattened by the wave erosion. Gyots are old sea mount whose top is close to sea level.
Trenches : the deepest place in the oceans. Narrow channels. Most occur in pacific.they associate with active volcanoes & earthquakes.
Volcanoes : volcanoes & volcanic island are common in ocean. They stand 1 km above the surrounding floor.