دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: finely crystalline, generally lightcoloured extrusive igneous rock com- posed largely of plagioclase feldspar with smaller amounts of dark-coloured minerals. Compare diorite.

n: sandstone composed largely of feldspar grains and deriving from granitic source rocks.

A sandstone containing 25% or more of feldspar, usually derived from igneous rock.

n: an extrusive igneous rock that is dense, fine grained, and often dark gray to black. Compare gabbro.

the most common volcanic rock. Usually fine grained.

an irregular intrusion of an igneous rock into another rock.

n: a type of metamorphism that occurs when an intruded body of molten igneous rock changes the rocks immediately around it, primarily ny heating and by chemical alteration.

n: intrusive. or platonic. generally coarse-grained igneous rock composed largely of plagioclase feldspar with smaller amounts of dark-colored minerals. Also known as black granite. Compare andesite.

n: 1. the emission of magma (as lava) at the earths surface. 2. the body of igneous rock produced by the process of extrusion.

a description of rock resulting from a magma breach to surface and exposed to atmospheric conditions during cooling.

n: igneous rock fanned from lava poured out on the earths surface.

n: an intrusive igneous rock with the same composition as basalt.