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.

Subscribe via EMail to the GeoWord of the Day.


slab joints . Joints produced in rock by the formation of closely spaced parallel fissures dividing the rock into thin slabs.

phototriangulation (pho''-to-tri-ang''-u-la'-tion). The addition of horizontal and/or vertical control points by photogrammetric methods, whereby "the measurements of angles and/or distances on overlapping photographs are related into a spatial solution using the perspective principles of the photographs" (ASP, 1966, p.1148); esp. aerotriangulation.

fuel-coolant interaction . Referring to an industrial analog to a phreatomagmatic explosion, involving a fuel such as molten iron and a coolant such as water. The interaction of the fuel and coolant has resulted in vapor explosions in industrial environments. Abbrev: FCI.

macphersonite (mac-pher'-son-ite). A pale amber, colorless or white orthorhombic mineral: Pb4(SO4)(CO3)2(OH)2 . It is a polymorph of susannite and leadhillite.

weir . (a) A small dam in a stream, designed to raise the water level or to divert its flow through a desired channel; e.g., a "leaping weir". (b) A notch in a levee, dam, embankment, or other barrier across or bordering a stream, through which the flow of water is regulated; e.g., a "wasteweir". Well-designed weirs usually have known dimensions and cross-section areas as a function of height above the base. Graduations of height allow rapid determination of hydraulic parameters, such as wetted perimeter, needed to calculate discharge.

structural province . A region whose geologic structure differs significantly from that of adjacent regions. It is generally coextensive with a physiographic province.

litharge (lith'-arge). A red or yellow tetragonal mineral: PbO . Cf: massicot. Syn: lead ocher. It is the Pb analogue of romarchite.

super-solidus intrusion breccia PGE deposit . A mineral-deposit type characterized by platinum-group element sulfide mineralization cutting mafic-ultramafic cumulates associated with an intrusive breccia formed by associated ultramafic dikes. Abbrev: SIB-type PGE deposit.

pull-apart basin . A topographic depression created by an extensional bend or extensional overstep along a strike-slip fault (Aydin and Nur, 1982). Syn: sag pond; rhombochasm.

minerocoenology (min''-er-o-coe-nol'-o-gy). The study of mineral associations in the broadest sense, such as the correlation of igneous rocks or magmatic provinces with their ore deposits (Thrush, 1968, p.712). Obsolete.

Pages

Subscribe to GeoWord of the Day