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31 terms

Chapter 2 P Vocabulary: Rocks: Materials of the Solid Earth

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Andesitic composition:
The composition of igneous rocks lying between felsic and mafic.
Basaltic Composition
A compositional group of igneous rock which indicates the rock contains substantial dark silicate minerals and calcium-rich plagioclase feldspar.
Bowen's reaction series
A concept proposed by N.L. Bowen that illustrates the relationship between magma and the minerals crystallizing from it during the formation of igneous rocks.
Chemical sedimentary rock
Sedimentary rock that is made up of material that was precipitated from water by either inorganic or organic means.
Coarse-grained texture
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.
Contact metamorphism
Changes in rocks that are created by the heat from a nearby magma body.
Crystallization
The growth and formation of crystalline solid from a gas or liquid.
Disseminated deposit
Any economic mineral deposit in which the desired mineral occurs as scattered particles in the rock but in good amounts to make the deposit an ore.
Evaporate
A sedimentary rock produced from material deposited from solution by means of evaporation of the water.
Extrusive
Igneous activity that takes place outside the crust.
Felsic
The group of igneous rocks that are composed of mainly feldspar and quartz.
Foliated
A texture of metamorphic rocks that gives the rock a layered appearance.
Fossil
The remains or traces of organisms that are preserved from the geologic past.
Glassy
A term used to describe the specific texture of specific igneous rocks like obsidian, which contains no crystals.
Granitic composition
A compositional group of rocks, igneous, that indicate a rocks composition to be composed of mainly light-colored silicates.
Hydrothermal solution
The hot, watery solution that escapes from a mass of magma during the later stages of crystallization. Hydrothermal solutions, solutions may alter the surrounding country of rock and are typically the source of significant ore deposits.
Igneous rock
A rock formed by the crystallization of molten magma.
Lithification
The process, usually cementation and/or compaction, of converting sediments to solid rock.
Mafic
Igneous rocks with a low level of silica content and a high iron-magnesium content.
Magma
A body of molten rock found at depth, including any dissolved gases and crystals.
Metamorphic rock
Rocks formed by the alteration of preexisting rock deep within Earth, though still in a solid state, because of heat, pressure, and/or chemically active fluids.
Metamorphism
The changes in mineral composition and texture of a rock subjected to high temperature and pressure within Earth.
Nonfoliated texture
The texture of rocks that do not exhibit foliation, or layered appearance.
Porphyritic texture
The texture of rocks consisting of large crystals embedded in a matrix of smaller crystals.
Regional metamorphism
Metamorphism associated with large-scale mountain-building processes.
Rock cycle
A model that illustrates the origin of the three basic rock types and the interrelatedness of Earth materials and processes.
Sediment
Unconsolidated particles formed by weathering and erosion of rock, by chemical precipitation from solution in water, or from the secretions of organisms and transported by water, wind, or glaciers.
Sedimentary rock
Rock created from the weathered products of preexisting rocks that have been transported, deposited, and lithified.
Strata
Parallel layers of sedimentary rock.
Texture
The shape, size, and distribution of the particles that collectively constitute a rock.
Ultramafic
Igneous rock made of up iron and magnesium-rich minerals.