Labeling the Ocean Floor – 10 Features, Shelf to Trench

All 10 features on the diagram

Show the list

Simple: 6 main features 6

Continental shelf Shallow sea floor off a continent, under 200 m of water.
Continental slope The steep drop from the shelf's edge toward the deep ocean.
Continental rise Gently sloping sediment from the foot of the slope to the plain.
Abyssal plain Flat, sediment-covered deep floor, 3,000 to 6,000 m down.
Mid-ocean ridge Volcanic mountains where plates spread apart; the top averages 2,500 m deep.
Ocean trench A long, narrow trough where one plate dives under another.

Deep ocean 4

Seamount An underwater mountain at least 1,000 m high, most an old volcano.
Guyot A seamount with a large, flat summit.
Rift valley A valley along the crest of a slow-spreading mid-ocean ridge.
Island arc A curved chain of volcanic islands beside a trench.

How this list was compiled: Read 2026-09-23. (1) U.S. National Park Service, Geologic Resources Inventory glossary, read from its data file https://www.nps.gov/common/uploads/sortable_dataset/geology/DBD85DC6-CA83-CEE3-0786454132D79FCD/nri-GlossaryTable.csv: continental shelf (under 200 m of water, from the shoreline to the slope), continental slope, continental rise, abyssal plain, seamount (1,000 m or higher, flat-topped or peaked), mid-ocean ridge, rift valley (along the crest of a mid-ocean ridge), oceanic trench (beside a volcanic arc above a subduction zone), island arc. (2) NOAA Ocean Exploration: What are abyssal plains?, https://oceanexplorer.noaa.gov/ocean-fact/what-are-abyssal-plains/ (3,000 to 6,000 m deep, flat, covered in sediment); What is a seamount?, https://oceanexplorer.noaa.gov/facts/seamounts.html (most are extinct volcanoes; guyots have large, flat summits); What is the mid-ocean ridge?, https://oceanexplorer.noaa.gov/facts/mid-ocean-ridge.html (average depth to the top 2,500 m; slow spreading forms a rift valley, fast spreading does not); What features form at plate tectonic boundaries?, https://oceanexplorer.noaa.gov/facts/plate-boundaries.html (deep seafloor trenches where plates converge). (3) NOAA National Ocean Service, What is a guyot?, https://oceanservice.noaa.gov/facts/guyot.html. (4) Wikipedia, Continental margin, https://en.wikipedia.org/wiki/Continental_margin, Abyssal plain, https://en.wikipedia.org/wiki/Abyssal_plain, and Oceanic trench, https://en.wikipedia.org/wiki/Oceanic_trench (long, narrow depressions of the ocean floor; the greatest depth measured, the Challenger Deep, is in one). Licence: own work

The drawing: Drawn for this site by script, 2026-09-23, with depths on one scale from NPS and NOAA figures. Licence: own work

How it works

The ocean floor is not flat. Leaving a continent it steps down from the shelf to the slope and rise, crosses the abyssal plain, climbs the mid-ocean ridge and drops into a trench.

Read the full guide

From the coast to the deep

The continental shelf lies under less than 200 m of water. At its edge the continental slope drops steeply, and the continental rise, a ramp of sediment, leads down to the abyssal plain, 3,000 to 6,000 m deep.

Mountains and trenches

Seamounts rise at least 1,000 m from the floor; a guyot is one with a flat top. The mid-ocean ridge forms where plates spread apart. Where one plate dives under another, a trench forms beside an island arc.

Across, the drawing keeps the features in order but squeezes the distances; up and down, the depths are to one scale.

Questions and answers

What are the features of the ocean floor?

From the coast out: continental shelf, continental slope, continental rise and abyssal plain, with seamounts and guyots on the plain, the mid-ocean ridge with its rift valley, and trenches beside island arcs.

What is the difference between a seamount and a guyot?

Both are underwater mountains at least 1,000 m high, most of them old volcanoes. A seamount usually rises to a peak; a guyot has a large, flat top.

What is the deepest part of the ocean floor?

The ocean trenches, long narrow troughs where one plate dives under another. The greatest ocean depth ever measured, the Challenger Deep, lies in one of them.