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.


bobtraillite . A vitreous gray, pale green, or brown hexagonal mineral: Na15Sr12Zr14Si42B6O138(OH)6•12H2O.

Butterworth filter . A frequency filter characterized by a very flat passband, often used as an alias filter. Sometimes called a maximally flat filter or trapezoidal filter (Sheriff and Geldart, 1995).

macroclimate (mac-ro-cli'-mate). The general climate of an extensive region or a country. See also: mesoclimate; microclimate.

fumarole mound . A small mound from which fumarole or solfatara gases escape.

alumino-katophorite . A hypothetical member of the amphibole mineral family; probably an unnecessary name for katophorite : Na2Ca(Fe2+4Al)(Si7Al)O22(OH)2.

clarotelain (clar-o-te'-lain). A transitional lithotype of coal characterized by the presence of telinite, with lesser amounts of other macerals. Cf: teloclarain. Syn: clarotelite.

oboyerite (o-boy'-er-ite). A white triclinic mineral: H6(Pb,Ca)6(Te4+O3)3(Te6+O6)2•2H2O .

greenstone [meta] . A field term applied to any compact dark-green altered or metamorphosed mafic igneous rock (e.g., spilite, basalt, gabbro, diabase) that owes its color to the presence of chlorite, actinolite, or epidote.

sanderite (san'-der-ite). An incompletely described mineral: MgSO4•2H2O.

anticyclone (an-ti-cy'-clone). An atmospheric high-pressure system with closed isobars, the pressure gradient being directed away from the center so that the near surface wind spirals outward in a clockwise direction in the Northern Hemisphere, counterclockwise in the Southern. It was named by Francis Galton in 1861. See also: cyclone.

Pages

Subscribe to GeoWord of the Day