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They are also known as composite volcanoes because they are created from multiple structures during different kinds of eruptions; the main conduit bringing magma to the surface branches into multiple secondary conduits and occasional laccoliths or sills, the branching conduits may form parasitic cones on the flanks of the main cone. [2]
The type and number of volcanoes required to be called a "field" is not well-defined. [1] Volcanic fields usually consist of clusters of up to 100 volcanoes such as cinder cones. Lava flows may also occur. They may occur as a monogenetic volcanic field or a polygenetic volcanic field.
There are several extinct volcanoes on Mars, four of which are vast shield volcanoes far bigger than any on Earth. They include Arsia Mons, Ascraeus Mons, Hecates Tholus, Olympus Mons, and Pavonis Mons. These volcanoes have been extinct for many millions of years, [33] but the European Mars Express spacecraft has found evidence that volcanic ...
The term composite volcano is used because strata are usually mixed and uneven instead of neat layers. [6] They are among the most common types of volcanoes; [7] more than 700 stratovolcanoes have erupted lava during the Holocene Epoch (the last 11,700 years), [8] and many older, now extinct, stratovolcanoes erupted lava as far back as Archean ...
They are formed by flexing of the oceanic lithosphere, developing on the ocean side of island arcs. Back-arc basin: They are also referred to as marginal seas and are formed in the inner, concave side of island arcs bounded by back-arc ridges. They develop in response to tensional tectonics due to rifting of an existing island arc.
The magma ascends to form an arc of volcanoes parallel to the subduction zone. Volcanic arcs are distinct from volcanic chains formed over hotspots in the middle of a tectonic plate. Volcanoes 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.
A hotspot volcano is center. [8] Movements of tectonic plates create volcanoes along the plate boundaries, which erupt and form mountains. A volcanic arc system is a series of volcanoes that form near a subduction zone where the crust of a sinking oceanic plate melts and drags water down with the subducting crust. [9]
Most hotspot volcanoes are basaltic (e.g., Hawaii, Tahiti). As a result, they are less explosive than subduction zone volcanoes, in which water is trapped under the overriding plate. Where hotspots occur in continental regions, basaltic magma rises through the continental crust, which melts to form rhyolites. These rhyolites can form violent ...