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Magma, molten or partially molten rock from which igneous rocks form. It usually consists of silicate liquid, although carbonate and sulfide melts occur as well. Magma migrates either at depth or to Earth’s surface and is ejected as lava.
Magma is extremely hot liquid and semi-liquid rock located under Earth’s surface. Earth has a layered structure that consists of the inner core, outer core, mantle, and crust. Much of the planet’s mantle consists of magma.
Igneous rocks are those that form via the process of melting and cooling. If they erupt from volcanoes onto the surface as lava, they are called extrusive rocks. By contrast, Intrusive rocks are formed from magma that cools underground.
Magma compositions vary, but will have eight main elements in different proportions. The most abundant elements are oxygen and silicon, followed by aluminum, iron, calcium, sodium, magnesium, and potassium.
How Magma Forms. Earth is divided into three general layers. The core is the superheated center, the mantle is the thick, middle layer, and the crust is the top layer on which we live. Magma originates in the lower part of Earth’s crust and in the upper portion of the mantle.
The two types are intrusive (from magma) and extrusive (from lava). Igneous rocks form through the cooling and solidification of magma or lava. These rocks are distinctly different from sedimentary and metamorphic rocks, which originate from the deposition of material at the Earth’s surface and the transformation of existing rocks under ...
Molten, or hot liquefied, rock located deep below the Earth’s surface is called magma. Magma typically is molten silicate material, although carbonate and sulfide magmas also occur. Magma moves up to the surface from deep within the Earth, and is ejected as lava. The magma carries crystals and fragments of unmelted rock.
Lava is the name for molten rock that has erupted onto the Earth's surface - the red-hot material spilling from volcanoes. Lava is also the name for the resulting solid rock. In contrast, magma is unseen. Any rock underground that is fully or partially melted qualifies as magma.
The implication is that magma reservoirs have differing modes of behavior: magmas are stored over the long term in largely crystalline, quiescent, conditions, punctuated by brief episodes of intense activity during the decades to centuries immediately prior to an eruption.
Igneous rocks solidify from molten rock (called magma within the Earth and lava on the surface). They are identified by mineral content and texture — the size and shape of their mineral grains.