The Online Encyclopedia and Dictionary






Oceanic trench

The oceanic trenches are several hundred kilometres long but narrow topographic depressions of the sea floor. They also are the deepest parts of the ocean floor. A trench marks the position at which the flexed, subducting slab begins to go under, on the convex side and between 50 and 250 km from a volcanic arc. Oceanic trenches typically extend 3 to 4km (1.9-2.5 mi) below the level of the surrounding oceanic floor. The deepest ocean depth to be sounded is in the Challenger Deep of the Mariana Trench at a depth of 10,991m (35,798 ft) below sea level.

Major oceanic trenches

See also

Last updated: 09-12-2005 02:39:13