eluvium [weath] . An accumulation of rock debris produced in place by the decomposition or disintegration of rock; a weathering product; a residue.
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.
polarization [seis] . The sense of displacement for a wave (such as an S-wave). A preferential direction of wave motion, as the component of S-waves whose motion is confined to a horizontal plane. A preferred orientation may also be imposed by anisotropy, for example, S-waves involving displacement parallel (or perpendicular) to vertical fractures in rocks.
serra (ser'-ra). (a) sierra. (b) A term used in Brazil for an elevated mountain zone supporting luxuriant vegetation. Etymol: Latin, "saw".
wax opal . Yellow opal with a waxy luster.
fenestrate (fe-nes'-trate, fe'-nes-trate). Having openings or transparent areas; perforated or reticulated. The term has been applied esp. to bryozoans possessing small windowlike openings between branches, arranged in a reticulate or anastomosing pattern; to corals having regularly perforated septa; and to pollen exhibiting large geometrically arranged holes in the exine. Syn: fenestrated.
fenestrate (fe-nes'-trate, fe'-nes-trate). Having openings or transparent areas; perforated or reticulated. The term has been applied esp. to bryozoans possessing small windowlike openings between branches, arranged in a reticulate or anastomosing pattern; to corals having regularly perforated septa; and to pollen exhibiting large geometrically arranged holes in the exine. Syn: fenestrated.
steel ore . A name given to various iron ores (esp. to siderite) because they were readily used for making steel.
solution mining . (a) The in-place dissolution of water-soluble mineral components of an ore deposit by permitting a leaching solution, usually aqueous, to trickle downward through the fractured ore to collection galleries at depth. It is a type of chemical mining. (b) The mining of soluble rock material, esp. salt, from underground deposits by pumping water down wells into contact with the deposit and removing the artificial brine thus created.
pisolite [mineral] (pi'-so-lite). A variety of calcite or aragonite.
patch reef . A moundlike or flat-topped organic reef, generally less than a kilometer across, isolated from other bioherms, less extensive than a platform reef, and frequently forming a part of a larger reef complex. Cf: reef patch; table reef, chapeiro.
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