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.

flat [lake] . (a) The low-lying, exposed, flat land of a lake delta or of a lake bottom. (b) The flat bottom of a desiccated lake in the arid parts of western U.S. Commonly used in the plural.

calcite bubble . A nonattached hollow sphere, usually of calcite, that has formed around a gas bubble on the surface of a cave pool. Syn: cave bubble .

glance . A mineral that has a splendent luster; e.g. chalcocite, or copper glance.

radiolarian ooze . A deep-sea pelagic sediment containing at least 30% opaline-silica tests of radiolarians. It is a siliceous ooze.

kinoite (kin'-o-ite). A blue monoclinic mineral: Ca2Cu2Si3O8(OH)4 .

Båth's law . A generalization in seismology that the largest aftershock occurring within a few days of a main shock has a magnitude of 1.2 units lower than that of the main shock (Richter, 1958, p.69).

conotheca (co-no-the'-ca). (a) Conoidal theca with a small circular aperture located at the terminus of a short neck developed irregularly in colonies of tuboid graptolithines (Whittington and Rickards, 1968). (b) The outer shell of ectocochleate cephalopods and of the phragmocone of endocochleate cephalopods.

fenitization (fen''-it-i-za'-tion). As generally used today, widespread alkali metasomatism of quartzo-feldspathic country rocks in the environs of carbonatite complexes.

Wolfcampian (Wolf-camp'-i-an). North American series: lowermost Permian (above Virgilian of Pennsylvanian, below Leonardian).

caltonite (cal'-to-nite). A dark-colored analcime-bearing basanite that contains microphenocrysts of olivine and clinopyroxene in a trachytic groundmass composed of feldspar laths, clinopyroxene, iron oxides, and analcime. It was named by Johannsen (1931) for Calton Hill, Derbyshire, England. Obsolete.


Subscribe to GeoWord of the Day