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Difficulty: MediumWater Cycle and Oceanography

A marine survey vessel records continuous sonar soundings across an ocean basin, charting bathymetric topography from a passive shoreline outward toward an offshore subduction boundary. What is the correct sequence of seafloor features the vessel encounters from the shallow coast to the deepest oceanic zone?

  1. 1Continental shelf: a gently sloping, shallow submerged edge of the continental landmass extending from the coast.
  2. 2Continental slope: a steeply inclined seaward descent connecting the shallow coastal margin to the deep sea floor.
  3. 3Continental rise: an apron of thick sediment accumulated at the base of the steep continental slope.
  4. 4Abyssal plain: an expansive, extremely flat benthic region covering vast areas of the deep ocean basin.
  5. 5Oceanic trench: a deep, narrow, steep-sided V-shaped depression formed where tectonic plates collide and subduct.

Answer

Continental shelf, Continental slope, Continental rise, Abyssal plain, Oceanic trench
Traveling seaward from a passive continental shoreline toward a subduction zone, the ocean floor follows a predictable topographic sequence: first, the shallow, gently sloping continental shelf; second, the steeply plunging continental slope; third, the sediment-rich continental rise at the base of the slope; fourth, the broad, flat abyssal plain; and finally, the steep, plunging oceanic trench formed at the convergent plate boundary.

Step-by-Step Solution

1
Identify the starting geological feature at the shoreline edge of the continent.
The continental shelf is the shallowest zone directly adjacent to the continental landmass.
Continental crust extends beneath shallow coastal waters before plunging into oceanic depths.
2
Determine the feature marking the sharp structural transition from shallow coastal waters to the deep ocean.
The continental slope represents the steep boundary between the continental shelf and the deep ocean floor.
The shelf break marks a distinct increase in slope angle descending rapidly toward the ocean basin.
3
Identify the sediment accumulation zone located at the foot of the slope.
The continental rise forms a gentle sediment wedge at the base of the continental slope.
Sediments transported down underwater canyons settle and merge to form this transitional apron.
4
Locate the expansive, level floor of the deep ocean basin.
The abyssal plain extends across vast distances beyond the continental rise.
Thick layers of marine sediments blanket the underlying volcanic crust to create exceptionally level terrain.
5
Identify the deepest oceanic depression at the convergent tectonic boundary.
The oceanic trench marks the deepest bathymetric feature where subduction occurs.
Convergent plate boundaries pull the ocean lithosphere downward into narrow chasms reaching extreme depths.

Key Concept

Ocean Floor Topography and Bathymetric Margins
Estimated Time:1m 0s
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Topics

Water Cycle and Oceanography

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