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Oceanic crust is formed at an oceanic ridge, while the lithosphere is subducted back into the asthenosphere at trenches. Oceanic trenches are prominent, long, narrow topographic depressions of the ocean floor. They are typically 50 to 100 kilometers (30 to 60 mi) wide and 3 to 4 km (1.9 to 2.5 mi) below the level of the surrounding oceanic ...
An oceanic trench is a type of convergent boundary at which two oceanic lithospheric slabs meet; the older (and therefore denser) of these slabs flexes and subducts beneath the other slab. Oceanic lithosphere moves into trenches at a global rate of about a tenth of a square meter per second.
At the deepest point, the trench is nearly 11,000 m deep (almost 36,000 feet). [38] [3] This is further below sea level than Mount Everest is above sea level, by over 2 kilometers. Volcanic arcs and oceanic trenches partly encircling the Pacific Basin form the so-called Pacific Ring of fire, a zone of frequent earthquakes and volcanic eruptions.
The abyssal zone or abyssopelagic zone is a layer of the pelagic zone of the ocean. The word abyss comes from the Greek word ἄβυσσος (ábussos), meaning "bottomless". [1] At depths of 4,000–6,000 m (13,000–20,000 ft), [2] this zone remains in perpetual darkness. [3] [4] It covers 83% of the total area of the ocean and 60% of Earth's ...
Oceanic crust and tectonic plates are formed and move apart at mid-ocean ridges. Abyssal hills are formed by stretching of the oceanic lithosphere. [25] Consumption or destruction of the oceanic lithosphere occurs at oceanic trenches (a type of convergent boundary, also known as a destructive plate boundary) by a process known as subduction.
Many organisms in the mesopelagic zone move up into the epipelagic zone at night, and retreat to the mesopelagic zone during the day, which is known as diel vertical migration. [8] These migrators can therefore avoid visual predators during the day and feed at night, while some of their predators also migrate up at night to follow the prey.
Depth of oceanic trenches seems to be controlled by age of the oceanic lithosphere being subducted. [5] Sediment fill in oceanic trenches varies and generally depends on abundance of sediment input from surrounding areas. An oceanic trench, the Mariana Trench, is the deepest point of the ocean at a depth of approximately 11,000 m (36,089 ft).
Oceanic trenches — the deepest parts of the ocean floor, typically formed when one tectonic plate slides under another. Geology portal; Subcategories.