type specimen . The single specimen on which the original description of a particular species is based, which serves as a permanent point of nomenclatural reference for application of the name of that species. The type specimen may be a holotype, a neotype, or a lectotype.
GeoWord of the Day
The GeoWord of the Day is a free service of the American Geosciences Institute. All of the terms and definitions are from the Glossary of Geology, 5th Edition Revised.
partial pressure . The pressure of a gas in the atmosphere which would be in solubility equilibrium with the dissolved form of the same gas at the temperature of the seawater. Used to evaluate the directions and magnitudes of the net fluxes of gases such as carbon dioxide, oxygen, or fluorocarbons across the air-sea interface.
lopezite (lo'-pez-ite). An orange-red triclinic mineral: K2Cr2O7 .
hydraulic [materials] . Hardening or setting under water; e.g. "hydraulic lime" or "hydraulic cement".
reduction body . A multicellular mass resulting from the disorganization of a sponge and capable of reorganizing into a sponge with a functional aquiferous system.
terranovaite . A colorless or bluish orthorhombic zeolite mineral: NaCa(Si,Al)20O40•~8H2O.
glacial striation . One of a series of long, delicate, finely cut, commonly straight and parallel furrows or lines inscribed on a bedrock surface by the rasping and rubbing of rock fragments embedded at the base of a moving glacier, and usually oriented in the direction of ice movement; also formed on the rock fragments transported by the ice. Cf: glacial groove. Syn: glacial scratch; glacial stria; drift scratch.
convection fractionation . Crystal fractionation brought about by the buoyancy driven convection of fractionated liquid away from stationary crystals that are growing "in place" as opposed to removal of crystals from a stationary liquid, e.g. crystal setting. Typically associated with boundary layer crystallization along the floor and sidewalls of an active magma body. See also: compositional convection .
Galperin geophone (Gal'-per-in). A geophone geometry consisting of a triphone with elements making an angle of 54° 35′ with the vertical, with an additional vertical geophone for redundancy (Sheriff, 2002). Named for E. I. Galperin, Russian geophysicist.
projected profile (pro-ject'-ed). A diagram that includes only those features of a series of profiles, usually drawn along several regularly spaced and parallel lines on a map, that are not obscured by higher intervening ground (Monkhouse and Wilkinson, 1952); it gives a panoramic effect with a distant skyline, a middleground, and a foreground, and it represents an outline landscape-drawing showing only summit detail. Cf: superimposed profile; composite profile.
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