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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 ...
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.
And, using the mobilistic concepts developed before, he correctly concluded that many millions of years later, the oceanic crust eventually descends along the continental margins where oceanic trenches—very deep, narrow canyons—are formed, e.g. along the rim of the Pacific Ocean basin. The important step Hess made was that convection ...
This reproductive strategy could be very useful in low energy environments such as the abyssal zone. Pseudoliparis swirei: the Mariana snailfish, or Mariana hadal snailfish, is a species of snailfish found at hadal depths in the Mariana Trench in the western Pacific Ocean. It is known from a depth range of 6,198–8,076 m (20,335–26,496 ft ...
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.
Spreading rate is the rate at which an ocean basin widens due to seafloor spreading. (The rate at which new oceanic lithosphere is added to each tectonic plate on either side of a mid-ocean ridge is the spreading half-rate and is equal to half of the spreading rate). Spreading rates determine if the ridge is fast, intermediate, or slow.
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).
The IBM trenches began to grow in length c., opening back-arc basins in the Philippine Sea. Between 30 and 17 Mya, the old age of the subducting Pacific Ocean floor (110-130 Ma) resulted in a very fast trench migration and new back-arc basins opening behind the trenches. [12]