kriging (krig'-ing). (a) A statistical technique employed in calculating grade and tonnage of ore reserves from sampling data. The data are handled by computer. Named for Danie Krige, a South African geostatistician. (b) A technique for interpolating which honors data points exactly. An output point is calculated as a linear combination of known data points. Kriging attempts to produce the best linear unbiased estimate. Used to interpolate between boreholes. Cf: cokriging .
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.
gravimeter (gra-vim'-e-ter). An instrument for measuring the gravitational acceleration due to the presence of the Earth's gravity field. There are two basic types of gravimeter: absolute-gravity instrument and relative-gravity instrument. Exploration gravimeters are of the second type. The gravitational force (i.e., force of gravitational attraction) on a unit mass in the exploration gravimeter is balanced by a spring arrangement. At each point of measurement, the position of a unit mass is altered by a change in the gravitational attraction of the Earth's mass. Recent developments in gravimeter design include accelerometer and magnetic levitation. Syn: gravity meter. See also: astatic gravimeter and zero-length spring.
group [geophys] . (a) The various geophones or hydrophones which collectively feed a single channel. The number of phones may vary from one to several hundred. A large group is sometimes called a patch. Syn: array [geophys]. (b) A source group that consists of several sources or source locations that are combined together to form one seismic trace. They may be activated together or combined subsequently.
geoinformatics . The application of modern information technology to organize, preserve, and distribute geoscience data and to facilitate and advance their analysis.
horizontal drainhole . An oil or gas well drilled parallel to the boundaries of a reservoir. It is usually nearly horizontal but not always.
trophocyte (troph'-o-cyte). An amoebocyte of a sponge that serves as a nourishing cell of an oocyte, embryo, or gemmule.
global tectonics . Tectonics on a global scale, such as tectonic processes related to very large-scale movement of material within the Earth; specif. plate tectonics. Cf: megatectonics.
garnet lherzolite . A lherzolite containing garnet as the dominant aluminum-rich mineral; stable at greater depths in the mantle than spinel lherzolite and plagioclase lherzolite.
arendalite (ar-en'-dal-ite). A dark-green variety of epidote from Arendal, southern Norway.
schrötterite (schröt'-ter-ite). An opaline variety of allophane rich in aluminum. Material from the type locality has been shown to be a mixture of glassy halloysite and earthy variscite.
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