corvusite (cor'-vus-ite). A submetallic blue-black, brown, or purplish mineral: (Na,Ca,K)(V5+,V4+,Fe2+)O20•4H2O. It is classed as a "vanadium bronze", and is an ore of vanadium. Syn: blue-black ore.
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.
porticus (por'-ti-cus). A distinctly asymmetrical apertural flap in the tests of some planktonic foraminifers (such as Ticinella and Praeglobotruncana ). It was originally defined as imperforate. Pl: portici.
channel [drill] . A cavity or passage in a faulty cementing job behind the casing in a borehole. Syn: holiday.
fluor (flu'-or). The original form of fluorite, still used chiefly in Great Britain. Etymol: Latin "fluere", "to flow".
laminar structure . A microstructure of rods, laths, blades, or tablets comprising sheets that are oriented parallel or nearly parallel to the depositional surface. This includes nacreous, seminacreous, plywood, matted, regularly foliated, and semifoliated structures (Carter, 1980a,b).
crest [sed struc] . The part of a ripple with an elevation of greater than half its total height (Blatt et al., 1980).
real-aperture radar (real-ap'-er-ture). A SLAR system in which azimuth resolution is determined by the length of the antenna and by the wavelength. The radar returns are recorded directly to produce images. Syn: brute-force radar.
aphanite (aph'-a-nite). Any fine-grained igneous rock whose components are not distinguishable with the unaided eye; a rock having aphanitic texture. The obsolescent syn. felsite has been sometimes restricted to the light-colored rocks with this texture and aphanite to the dark-colored (Johanssen, 1939, p.201). Adj: aphanitic [ign]. Cf: felsite; phanerite.
caking coal (cak'-ing). Coal that softens and agglomerates when heated, and on quenching produces a hard gray cellular coke. Not all caking coals are good coking coals. Syn: binding coal.
formation-volume factor (for-ma'-tion-vol'-ume). The factor applied to convert a barrel of gas-free oil in a stock tank at the surface into an equivalent amount of oil in the reservoir. It generally ranges between 1.14 and 1.60. Cf: shrinkage factor.
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