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When magma cools it begins to form solid mineral phases. Some of these settle at the bottom of the magma chamber forming cumulates that might form mafic layered intrusions. Magma that cools slowly within a magma chamber usually ends up forming bodies of plutonic rocks such as gabbro, diorite and granite, depending upon the composition of the magma.
Full volcanic planet, magma ocean in surface. Magma oceans are vast fields of surface magma that exist during periods of a planet's or some natural satellite's accretion when the celestial body is completely or partly molten. [1] In the early Solar System, magma oceans were formed by the melting of planetesimals and planetary impacts. [1]
While cooling, the magma evolves in composition because different minerals crystallize from the melt. 1: olivine crystallizes; 2: olivine and pyroxene crystallize; 3: pyroxene and plagioclase crystallize; 4: plagioclase crystallizes. At the bottom of the magma reservoir, a cumulate rock forms.
The next unit is composed of 0.3–0.7 km thick pillow basalts, formed by the quenching of basaltic magma as it erupts into ocean water. Under the pillow basalts is a basaltic sheeted dike complex, that represent cooled magma conduits. The bottom units represent the crystallized magma chamber, feeding the mid-ocean ridge at which the crust was ...
Magma mixing is the process by which two magmas meet, comingle, and form a magma of a composition somewhere between the two end-member magmas. Magma mixing is a common process in volcanic magma chambers, which are open-system chambers where magmas enter the chamber, [ 10 ] undergo some form of assimilation, fractional crystallisation and ...
The magmatic aspects of plate tectonics tends to gradual segregation within or between the mantle and crust. As magma forms, the initial melt is composed of the more silicic phases that have a lower melting point. This leads to partial melting and further segregation of the lithosphere. In addition the silicic continental crust is relatively ...
Intermediate composition magma, such as andesite, tends to form cinder cones of intermingled ash, tuff and lava, and may have a viscosity similar to thick, cold molasses or even rubber when erupted. Felsic magma, such as rhyolite, is usually erupted at low temperature and is up to 10,000 times as viscous as basalt. Volcanoes with rhyolitic ...
Supervolcano eruptions are possible only when an extraordinarily large magma chamber forms at a relatively shallow level in the crust. However, the rate of magma production in tectonic settings that produce supervolcanoes is quite low, around 0.002 km 3 year −1, so that accumulation of sufficient magma for a supereruption takes 10 5 to 10 6 ...