19 terms

Physical Features of the SeaFloor

Ring shaped island of coral reefs and coral debris; often form over sinking, inactive volcanoes
a huge underwater volcanic mountain that may emerge from the ocean surface as an island
Abyssal Plains
Flat, sediment covered ocean floor between the continental rise and oceanic ridge
Abyssal Hills
small, sediment covered inactive volcanoes less than 200m in height.
Oceanic Trench
an arc-shaped depression in the deep ocean floor with very steep sides and a flat sediment filled bottom; associated with a subduction zone. Most occur in the Pacific Ocean
Oceanic Ridge
a continuous elevated zone on the floor of all the major ocean basins and varying in width from 500 to 5000 kilometers (300 to 3000 miles). the rifts at the crests of these ridges represent divergent plate boundaries
a flat topped submerged inactive volcano
Hydrothermal Vent
A spring of hot, mineral- and gas-rich seawater found on some oceanic ridges in zones of active seafloor spreading.
Continental Rise
the gently sloping section of the continental margin located between the continental slope and the abyssal plain
Continental Slope
The edge of a continent that drops steeply down to the deep ocean floor
Continental margin
that portion of the seafloor adjacent to the continents. it may include the continental shelf, continental slope, and continental rise
Submarine canyon
Deep, V-shaped valley running roughly perpendicular to shoreline and cutting across the edge of the continental shelf and slope
the discovery and study of submerged contours
active margin
Continental margins near edges of converging plates- high earthquake and volcanic activity mainly in Pacific.
passive margin
the continental margin near an area of lithospheric plate divergence; also called Atlantic-type margin
turbidity current
Underwater "Avalanche" of abrasive sediments thought responsible for the deep sculpturing of submarine canyons and as a means for sediments accumulating on an abyssal plain
island arc
A string of islands formed by the volcanoes along a deep-ocean trench.
Continental shelf
The flat or gently sloping land that lies submerged around the edges of a continent and that extends from the shoreline out to a continental slope
Shelf break
Abrupt increase in slope at junction between continental shelf and continental slope