n. (context geology English) one of the major groups of rock that makes up the crust of the Earth; formed by the cooling of molten rock, either below the surface (intrusive) or on the surface (extrusive)
n. rock formed by the solidification of molten magma
Igneous rock (derived from the Latin word ignis meaning fire) is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or lava. Igneous rock may form with or without crystallization, either below the surface as intrusive ( plutonic) rocks or on the surface as extrusive ( volcanic) rocks. This magma can be derived from partial melts of existing rocks in either a planet's mantle or crust. Typically, the melting is caused by one or more of three processes: an increase in temperature, a decrease in pressure, or a change in composition.
Usage examples of "igneous rock".
It's not right to put yourself forward like that,' Sister Igneous Rock said.
Five thousand five hundred feet was the level at which they expected to reach the anticline and hanging over me all the time was the knowledge that it wasn't oil we were going to strike there, but the sill of igneous rock that had stopped Campbell Number One.
Even to his relatively untrained eye, this was a place where a volcanic fissure had opened ages ago, allowing igneous rock to thrust sharply upward through the sedimentary layers of the older ground.
On the steep slope of igneous rock no grass had managed to get hold, although a few hardy weeds clung to it.
We climbed back again to the peak of igneous rock where we had sat before.
That was why she had not let herself remember that igneous rock would never be involved with fossilization.
There's a sizable dike of blackish igneous rock a few hundred meters to the east of us.
After a long time the flats closed in around them and then folded into blinding gypsum dunes shimmering with mirages, among which weathered turrets of igneous rock poked up.
The resultant body of molten liquid, called magma, will solidify to produce the igneous rock, granite, but if it is still in liquid form as it approaches the surface, lava results.
Owen Meany used to say that we residents of Gravesend were sitting over a bona fide outcrop of intrusive igneous rock.
The entrance was little more than a large hole in the side of an old igneous rock formation, but it was large enough for L'Indasha to crawl through and retrieve a bucket full of ice.
Arandur is a rare natural metal found in igneous rock, usually as streaks of blue-green ore amid vitreous glass.
This rose in a sheer cliff-face of some blue-black igneous rock on which grew huge patches of a blue-green lichen.
They were black and bluish-green, looking like a glassy igneous rock with huge splotches of lichen covering at least a quarter of the surface.