Search results
Results from the WOW.Com Content Network
Igneous rock (igneous from Latin igneus 'fiery'), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava. The magma can be derived from partial melts of existing rocks in either a planet 's mantle or crust.
Magmatism. Geological map showing the Gangdese batholith, which is a product of magmatic activity about 100 million years ago. 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 ...
Magma consists of liquid rock that usually contains suspended solid crystals. [14] As magma approaches the surface and the overburden pressure drops, dissolved gases bubble out of the liquid, so that magma near the surface consists of materials in solid, liquid, and gas phases.
Rocks in the lower crust and the upper mantle are subject to partial melting. The rate of partial melting and the resultant silicate melt composition depend on temperature, pressure, flux addition (water, volatiles) and the source rock composition. [4] In oceanic crust, decompression melting of mantle materials forms basaltic magma.
Granite (/ ˈɡrænɪt / GRAN-it) is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies underground.
Igneous differentiation. In geology, igneous differentiation, or magmatic differentiation, is an umbrella term for the various processes by which magmas undergo bulk chemical change during the partial melting process, cooling, emplacement, or eruption. The sequence of (usually increasingly silicic) magmas produced by igneous differentiation is ...
Plutonism. Plutonism is the geologic theory that the igneous rocks forming the Earth originated from intrusive magmatic activity, with a continuing gradual process of weathering and erosion wearing away rocks, which were then deposited on the sea bed, re-formed into layers of sedimentary rock by heat and pressure, and raised again.
The tholeiitic magma series (/ ˌθoʊliˈaɪtɪk /) is one of two main magma series in subalkaline igneous rocks, the other being the calc-alkaline series. A magma series is a chemically distinct range of magma compositions that describes the evolution of a mafic magma into a more evolved, silica rich end member. Rock types of the tholeiitic ...