Chapter 3 Vocab Flashcards
Compositional category for igneous rocks found near the middle of bowens reaction series. Igneous rocks having a mineral makeup between that of granny and basalt, after the common volcanic rock andesite.
Andesitic Composition
A texture of igneous rocks in which the crystals are too small for individual minerals to be distinguished with the unaided eye.
Aphanitic Texture
Term used to describe igneous rocks that contain abundant dark (ferromagnesian) minerals and about 50 percent silica.
Basaltic Composition
A large mass of igneous rock that formed when magma was emplaced at depth, crystallized, and was subsequently exposed by erosion.
Batholiths
A concept proposed by N.L. Bowen that illustrates the relationship between magma and the minerals crystallizing from it during the formation of igneous rock.
Bowen’s Reaction Series
An igneous rock texture in which the crystals are roughly equal in size and large enough so that individual minerals can be identified with the unaided eye.
Coarse-grained texture/phaneritic texture
A pattern of cracks that forms during cooling molten rock to generate columns.
Columnar joints
A term used to describe intrusive igneous masses that form parallel to the bedding if the surrounding rock.
Concordant
The formation and growth of a crystalline solid from a liquid or gas.
Crystallization
Melting that occurs as rock ascends due to a drop in confining pressure.
Decompression melting
A tabular-shaped intrusive igneous feature that cuts trough the surrounding rock.
Dikes
A term used to describe plugins that cut across existing rock structures, such as bedding planes.
Discordant
Igneous activity that occurs at earths surface.
Extrusive igneous rock
A term derived from feldspar and silica. It is a term used to describe granitic ingenious rocks.
Felsic
An igneous rock texture resulting from consolidation of indivisible rock fragments that are ejected during a violent eruption.
Fragmental texture
The gradual increase in temperature with depth in the crust
Geothermal gradient
Natural glass produced when molten lava cools too rapidly to permit crystallization.
Glass
A term used to describe the texture of certain igneous rocks, such as obsidian, that contain no crystals.
Glassy texture
The matrix of smaller crystals within an igneous rock that has porphyritic texture
Ground mass
Igneous rocks composed mainly of light colored silicates are said to have this composition.
Granitic composition
The hot watery solution that escapes from a mass of magma urging the later stages of crystallization.
Hydrothermal solutions
A rock formed by the crystallization of molten magma.
Igneous rocks
Compositional category for igneous rocks found near the middle of bowens reactions series, mainly amphibole and the interim date plagioclase feldspars.
Intermediate composition
Igneous rock that formed below earths surface
Intrusions
A massive, concordant
Laccoliths
