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For instance, a magma of gabbroic composition can produce a residual melt of granitic composition if early formed crystals are separated from the magma. [92] Gabbro may have a liquidus temperature near 1,200 °C, [ 93 ] and the derivative granite-composition melt may have a liquidus temperature as low as about 700 °C. [ 94 ]
The internal structure of Earth are the layers of the Earth, excluding its atmosphere and hydrosphere. The structure consists of an outer silicate solid crust , a highly viscous asthenosphere , and solid mantle , a liquid outer core whose flow generates the Earth's magnetic field , and a solid inner core .
Earth's mantle is a layer of silicate rock between the crust and the outer core. It has a mass of 4.01 × 10 24 kg (8.84 × 10 24 lb) and makes up 67% of the mass of Earth. [ 1 ] It has a thickness of 2,900 kilometers (1,800 mi) [ 1 ] making up about 46% of Earth's radius and 84% of Earth's volume.
Magmatism is the emplacement of magma within and at the surface of the outer layers of a terrestrial planet, which solidifies as igneous rocks. It does so through magmatic activity or igneous activity, the production, intrusion and extrusion of magma or lava. Volcanism is the surface expression of magmatism.
The Magsat satellite and later satellites have used 3-axis vector magnetometers to probe the 3-D structure of the Earth's magnetic field. The later Ørsted satellite allowed a comparison indicating a dynamic geodynamo in action that appears to be giving rise to an alternate pole under the Atlantic Ocean west of South Africa.
A magma chamber is a large pool of liquid rock beneath the surface of the Earth. The molten rock, or magma , in such a chamber is less dense than the surrounding country rock , which produces buoyant forces on the magma that tend to drive it upwards. [ 1 ]
Over time the Earth began to cool as planetary accretion slowed and heat stored within the magma ocean was lost to space through radiation. A theory for the initiation of magma solidification states that once cool enough, the cooler base of the magma ocean would begin to crystallise first.
Earth's surface is continually being shaped by internal plate tectonic processes including earthquakes and volcanism; by weathering and erosion driven by ice, water, wind and temperature; and by biological processes including the growth and decomposition of biomass into soil. [119] [120]