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Another important water producing reaction that occurs during the eclogite facies is the dehydration of the hydrous phyllosilicate phlogopite by the reaction below. This reaction can also trigger significant mantle melting and volcanism. Aside from triggering mantle melt, this reaction may also trigger partial melting of the subducting slab itself.
A region where this process occurs is known as a subduction zone, and its surface expression is known as an arc-trench complex. The process of subduction has created most of the Earth's continental crust. [1] Rates of subduction are typically measured in centimeters per year, with rates of convergence as high as 11 cm/year. [2]
Magmatism along strike-slip faults is the process of rock melting, magma ascent and emplacement, associated with the tectonics and geometry of various strike-slip settings, most commonly occurring along transform boundaries at mid-ocean ridge spreading centres [1] and at strike-slip systems parallel to oblique subduction zones. [2]
The forearc mantle extends from where the subducting slab meets the cold nose of the mantle wedge, this occurs at depths from 10–40 km. [1] Low seismic attenuation, and high seismic velocities characterize this region. There is a boundary between this low attenuation region and a high attenuation region on the forearc side of the arc ...
The processing of oceanic crust, lithosphere, and sediment through a subduction zone decouples the water-soluble trace elements (e.g., K, Rb, Th) from the immobile trace elements (e.g., Ti, Nb, Ta), concentrating the immobile elements in the oceanic slab (the water-soluble elements are added to the crust in island arc volcanoes).
At subduction zones, slabs of oceanic crust sink into the mantle, dehydrate, and release volatiles which lower the melting temperature and give rise to volcanic arcs and back-arc extensions. Several volcanic provinces, however, do not fit this simple picture and have traditionally been considered exceptional cases which require a non-plate ...
Obduction zones occurs when the continental plate is pushed under the oceanic plate, but this is unusual as the relative densities of the tectonic plates favours subduction of the oceanic plate. This causes the oceanic plate to buckle and usually results in a new mid-ocean ridge forming and turning the obduction into subduction.
In geology, the slab is a significant constituent of subduction zones. [1] Subduction slabs drive plate tectonics by pulling along the lithosphere to which they attach in a process known as slab pull and by inducing currents in the mantle via slab suction. [2] The slab affects the convection and evolution of the Earth's mantle due to the ...