magma lava lava flow pyroclastic materials igneous rock volcanic (extrusive igneous) rock plutonic (intrusive igneous) rock felsic magma mafic magma intermediate magma
viscosity magma chamber Bowen s reaction series hot spot mantle plume crystal settling assimilation country rock magma mixing aphanitic texture
phaneritic texture porphyritic texture vesicle pyroclastic (fragmental) texture pluton concordant pluton discordant pluton dike sill laccolith
volcanic pipe volcanic neck batholith stock stoping
Molten rock material generated within Earth. Magma that reaches Earth s surface. A stream of magma flowing over Earth s surface. Fragmental substances, such as ash, that are explosively ejected from a volcano. Any rock formed by cooling and crystallization of magma or lava or the consolidation of pyroclastic materials. An igneous rock formed when magma is extruded onto Earth s surface where it cools and crystallizes, or when pyroclastic materials become consolidated. Igneous rock that formed from magma intruded into or formed in place within the crust. Magma with more than 65% silica and considerable sodium, potassium, and aluminum, but little calcium, iron, and magnesium. Magma with between 45% to 52% silica and proportionately more calcium, iron, and magnesium than intermediate and felsic magma. Magma with a silica content between 53% to 65% and an overall composition intermediate between mafic and felsic magma.
A fluid s resistance to flow. A reservoir of magma within Earth s upper mantle or lower crust. A series of minerals that form in a specific sequence in cooling magma or lava; originally proposed to explain the origin of intermediate and felsic magma from mafic magma. Localized zone of melting below the lithosphere that probably overlies a mantle plume. A cylindrical mass of magma rising from the mantle toward the surface; recognized at the surface by a hot spot, an area such as the Hawaiian Islands where volcanism takes place. The physical separation and concentration of minerals in the lower part of a magma chamber or pluton by crystallization and gravitational settling. A process whereby magma changes composition as it reacts with country rock. Any preexisting rock that has been intruded by a pluton or altered by metamorphism. The process whereby magmas of different composition mix together to yield a modified version of the parent magmas. A texture in igneous rocks in which individual mineral grains are too small to be seen without magnification; results from rapid cooling of magma and generally indicates an extrusive origin.
Igneous rock texture in which minerals are easily visible without magnification. An igneous texture with minerals of markedly different sizes. A small hole or cavity formed by gas trapped in cooling lava. A fragmental texture characteristic of igneous rocks composed of pyroclastic materials. An intrusive igneous body that forms when magma cools and crystallizes within the crust, such as a batholith or sill. Intrusive igneous body whose boundaries parallel the layering in the country rock. Pluton with boundaries that cut across the layering in the country rock. A tabular or sheetlike discordant pluton. A tabular or sheetlike concordant pluton A concordant pluton with a mushroom like geometry.
The conduit connecting the crater of a volcano with an underlying magma chamber. An erosional remnant of the material that solidified in a volcanic pipe. An irregularly shaped, discordant pluton with at least 100 km2 of surface area. An irregularly shaped discordant pluton with a surface area smaller than 100 km2. A process in which rising magma detaches and engulfs pieces of the country rock.