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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.
In subduction zones, the ultramafic rock of the upper mantle is melted by the addition of volatiles from the subducting plate. The subducting oceanic crust carries water and other volatiles into the mantle, primarily in the form of hydrous minerals which form as a result of the interaction of oceanic crust and seawater. [1]
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]
Magmas produced in subduction zone regions have high volatile contents. This water is derived from the breakdown of hydrous minerals in the subducting slab, as well as water in the oceanic plate from percolation of seawater. This water rises from the subducting slab to the overriding mantle wedge.
At spreading boundaries where plates move apart, the asthenosphere decompresses and melts to form new oceanic crust. 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 ...
Partial melting is the phenomenon that occurs when a rock is subjected to temperatures high enough to cause certain minerals to melt, but not all of them. Partial melting is an important part of the formation of all igneous rocks and some metamorphic rocks (e.g., migmatites), as evidenced by a multitude of geochemical, geophysical and petrological studies.
Investigators are trying to determine how a woman got past multiple security checkpoints this week at New York’s JFK International Airport and boarded a plane to Paris, apparently hiding in the ...
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 ...