4/9/2023 0 Comments Volcanic age wikiVolcanoes often form one after another as the plate moves over the hotspot, and so the volcanoes progress in age from one end of the chain to the other. Volcanic arcs are distinct from volcanic chains formed over hotspots in the middle of a tectonic plate. The magma ascends to form an arc of volcanoes parallel to the subduction zone. Volatiles such as water drastically lower the melting point of the mantle, causing some of the mantle to melt and form magma at depth under the overriding plate. The heat and pressure break down the hydrous minerals in the plate, releasing water into the overlying mantle. As the oceanic plate is subducted, it is subjected to increasing pressure and temperature with increasing depth. The oceanic plate is saturated with water, mostly in the form of hydrous minerals such as micas, amphiboles, and serpentine minerals. Volcanic arcs typically parallel an oceanic trench, with the arc located further from the subducting plate than the trench. With the belt arranged in an arc shape as seen from above. Volcanic arc formation along a subducting plateĪ volcanic arc (also known as a magmatic arc : 6.2 ) is a belt of volcanoes formed above a subducting oceanic tectonic plate,
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