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Subduction is the driving force behind plate tectonics, and without it, plate tectonics could not occur. [12] Oceanic subduction zones are located along 55,000 km (34,000 mi) of convergent plate margins, [13] almost equal to the cumulative plate formation rate 60,000 km (37,000 mi) of mid-ocean ridges. [14]
The continental crust on the downgoing plate is deeply subducted as part of the downgoing plate during collision, defined as buoyant crust entering a subduction zone. An unknown proportion of subducted continental crust returns to the surface as ultra-high pressure (UHP) metamorphic terranes, which contain metamorphic coesite and/or diamond plus or minus unusual silicon-rich garnets and/or ...
Subduction zones occur where an oceanic plate meets a continental plate and is pushed underneath it. Subduction zones are marked by oceanic trenches . The descending end of the oceanic plate melts and creates pressure in the mantle , causing volcanoes to form.
The subduction zone can be defined by a plane where many earthquakes occur, called the Wadati–Benioff zone. [1] These collisions happen on scales of millions to tens of millions of years and can lead to volcanism, earthquakes, orogenesis, destruction of lithosphere, and deformation. Convergent boundaries occur between oceanic-oceanic ...
At the consumption edges of the plate, the material has thermally contracted to become dense, and it sinks under its own weight in the process of subduction usually at an oceanic trench. Subduction is the descending component of mantle convection. [5] This subducted material sinks through the Earth's interior.
To map the subduction zone, researchers at sea performed active source seismic imaging, a technique that sends sound to the ocean floor and then processes the echoes that return. The method is ...
When oceanic plates diverge, tensional stress causes fractures to occur in the lithosphere. The motivating force for seafloor spreading ridges is tectonic plate slab pull at subduction zones, rather than magma pressure, although there is typically significant magma activity at spreading ridges. [3]
Lawsonite does not release water until approximately 300 km depth and is the last hydrous mineral to do so. [ 1 ] [ 11 ] Metamorphic dehydration reactions are prominent within the subducting slab during subduction, giving rise to liquid phases that contain fluid-mobile trace elements due to the breakdown of hydrous minerals such as phengite ...