grid smoothing . A method of smoothing sharp irregularities in potential-field measurements that arise from very shallow disturbances. A grid is drawn on a contour map and the smoothed value at a grid intersection is the average of values a fixed small distance away.
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.
oil-water contact (oil-wa'-ter). The boundary surface between an accumulation of oil and the underlying bottom water. Syn: oil-water interface.
danaite (da'-na-ite). A variety of arsenopyrite containing cobalt.
capilla (cap-il'-la). A very fine radial ridge on the external surface of a brachiopod shell; there are usually more than 25 capillae in a width of 10 mm. Cf: costa [paleont]; costella.
cylindrical fold . A fold that can be generated or reproduced by movement of a line with fixed orientation through space. Cf: conical fold; cylindroidal fold .
Lake George diamond . Colorless, doubly terminated quartz crystal from Herkimer County, N.Y. See also: Herkimer diamond.
drizzle . A form of liquid precipitation consisting of water droplets having diameters between 0.2 and 0.5 mm (0.01 and 0.02 in.); most often falls from low stratus clouds.
pediplain (ped'-i-plain). A term proposed by Maxson and Anderson (1935, p.94) for an extensive thinly alluviated erosion surface formed in a desert region by the coalescence of two or more adjacent pediments and occasional desert domes, and representing the end result (the "peneplain") of the mature stage of the arid erosion cycle. Howard (1942) objected to the term because the surface to which it is applied is not wholly at the base of a slope and is not a "plain" in the true geomorphic sense. Cf: pediplane; coalescing pediment. Syn: panfan; desert peneplain; desert plain.
hydration reaction (hy-dra'-tion). A metamorphic reaction that results in the formation of hydrous minerals. Cf: dehydration reaction.
dalles . (a) The rapids in a deep, narrow stream confined between the rock walls of a canyon or gorge; e.g. The Dalles of the Columbia River where it flows over columnar basalt. (b) A steep-sided part of a stream channel, near the dalles proper, marked by clefts, ravines, or gorges; e.g. along the Wisconsin River, Wisc. Etymol: French plural of dalle, "gutter". Syn: dells.
Pages
