Earth Science 11th Edition Vocabulary Chapter 3

By Jessica Hinton (GLY 1001 Student North Campus Fall 2006)


Andesitic composition- See Intermediate composition


Basaltic composition- A compositional group of igneous rocks indicating that 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 relationships between magma and the minerals crystallizing from it during the formation of igneous rocks


Chemical sedimentary rock- Sedimentary rock consisting of material that was precipitated form water by either


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 rock caused by the heat from a nearby magma body


Crystallization – the formation and growth of a crystalline solid from a liquid or gas


Crystal settling- During the crystallization of a mineral as determined by its internal arrangement of atoms


Detrital sedimentary rock – Rock formed from the accumulation of material that originated and was transported in form of solid particles derived form both mechanical and chemical weathering.


Disseminated deposit – Any economic mineral deposits in which the desired mineral occurs as scattered particles in the rock but in the rock but in sufficient quality to make the deposit an ore


Evaporate- A sedimentary rock formed of material deposited from solution by evaporation of the water


Extrusive – Igneous activity that occurs outside the crust


Felsic- The group of igneous rocks composed primarily of feldspar and quartz


Fine-grained texture- A texture if igneous rocks in which the crystals are too small for individual minerals to be distinguished with the unaided eye


Fossils- The remains or traces of organisms preserved from the geologic past

Foliated texture – A texture of metamorphic rocks that gives the rock a layered appearance


Glassy texture- A term used to describe the texture of certain igneous rocks, such as obsidian, that contain no crystals


Granitic composition- A compositional group of igneous rocks that indicates a rock is composed almost entirely of light-colored silicates 


Hydrothermal solution- The hot, watery solution that escapes from a mass of magma during the later stages of crystallization. Such solutions may alter the surrounding country rock and are frequently the source of significant ore deposits


Igneous rock- A rock formed by the crystallization of molten magma


Intermediate composition- The composition of igneous rocks lying between felsic and mafic


Intrusive rock – Igneous rock that formed below Earth’s surface


Lava- Magma that reaches Earth’s surface


Lithification- The process, generally cementation and /or compaction, of converting sediments to solid rock


Mafic- Igneous rocks with a low silica content and a high iron-magnesium content


Magma- A body of molten rock found at depth, including any dissolved gases and crystals


Magmatic differentiation- The process of generating more that one rock type form a single magma


Metamorphic rock- Rocks formed by the alteration of preexisting rock deep within Earth (but still in the solid state) by 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- Metamorphic rocks that do not exhibit foliation


Pegmatite- A very coarse-grained igneous rock (typically granite) commonly found as a dike associated with a large mass of plutonic rock that has smaller crystals. Crystallization in a water-rich environment is believed to be responsible for the very large crystals


Porphyritic texture- An igneous texture consisting of large crystals embedded in a matrix of much 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 created by the 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 formed from the weathered products of preexisting rocks that have been transported, deposited, lihified




Texture- The size, shape, and distribution of the particles that collectively constitute a rock


Thermal metamorphism- See Contrast metamorphism


Ultramafic composition- igneous rocks composed mainly of iron and magnesium-rich minerals


Vein deposit- A mineral filling a fracture or fault in a host rock. Such deposits have a sheet like, or tabular, form