Facts about Magma
Primary melts derived from the mantle are especially important, and are known as primitive melts or primitive magmas.
Conversely, the loss of water and volatiles from a body of magma may cause it to essentially freeze or solidify.
The melting of solid rock to form magma is controlled by three physical parameters: its temperature, pressure, and composition.
Viscosity is a key melt property in understanding the behavior of magmas.
Some granite-composition magmas are eutectic (or cotectic) melts, and they may be produced by various degrees of partial melting, as well as by fractional crystallization.
By finding the primitive magma composition of a magma series, it is possible to model the composition of the mantle from which a melt was formed.
Magmas that are more mafic, such as those that form basalt, are generally hotter and less viscous than those that are more silica-rich, such as magmas that form rhyolite.
The composition of magma is commonly correlated with the environment of its formation.
The degree of partial melting is critical for determining the type of magma produced.
The study of magma helps us understand the structure, composition and evolution of the Earth's crust and mantle over geological time.
Magma is capable of intrusion into adjacent rocks, extrusion onto the surface as lava, or ejected explosively as tephra to form pyroclastic rock.