5,021 articles
Diamond core drilling
Diamond core drilling is a rotary drilling method in which a diamond-impregnated bit cuts a solid cylinder of rock, called a core, for examination at the surface.
Diamond dust
Diamond dust is a form of precipitation of very small, unbranched ice crystals that fall slowly from an apparently cloudless sky, typically in cold polar regions.
Diapycnal mixing
Diapycnal mixing is the turbulent transport of heat, salt, and tracers across density surfaces in stratified fluids, driven mainly by breaking internal waves and supplying the energy the ocean's overturning circulation needs.
Diaspore
Diaspore is an aluminum oxide hydroxide mineral, a principal aluminum-bearing component of bauxite alongside gibbsite and böhmite, and a color-change gemstone sold as Zultanite or Csarite.
Diatomaceous earth
Diatomaceous earth, also called diatomite or kieselguhr, is a soft, finely porous siliceous sedimentary rock made of fossilized diatom skeletons, used mainly as a filter aid and insecticide.
Diavik Diamond Mine
The Diavik Diamond Mine was a Rio Tinto diamond mine on an island in Lac de Gras, Northwest Territories, Canada, producing over 150 million carats from 2003 to 2026.
Dickite
Dickite is a clay mineral of the kaolinite group, one of three natural polytypes alongside kaolinite and nacrite, named for Allan B. Dick, who described Welsh material in 1888.
Didymosphenia geminata
Didymosphenia geminata, commonly called didymo or rock snot, is a freshwater diatom native to northern Europe and North America that forms dense streambed mats in nutrient-poor rivers worldwide since the 1990s.
Diel vertical migration
Diel vertical migration is the daily movement of aquatic animals toward the surface at night and into deeper water by day, the largest synchronized movement of biomass on Earth.
Dieng Volcanic Complex
Dieng Volcanic Complex (Kompleks Vulkanik Dieng): a late Quaternary complex volcano and highland plateau in Central Java, Indonesia, with active phreatic craters, a deadly 1979 CO2 eruption, geothermal fields, and ancient Hindu temples.
Differential interferometric SAR
Differential interferometric SAR (DInSAR) is a radar remote-sensing technique comparing SAR images from repeated satellite passes to measure ground deformation from earthquakes, volcanoes, and subsidence with millimeter precision.
Differential interferometry
Differential interferometry (DInSAR) is a satellite radar remote-sensing method that compares SAR images acquired at different times to measure millimeter-scale ground deformation from earthquakes, volcanoes, landslides, and subsidence.
Differential optical absorption spectroscopy
Differential optical absorption spectroscopy (DOAS) is a spectroscopic technique that retrieves atmospheric trace-gas concentrations, such as NO2, SO2, and ozone, from UV and visible absorption spectra.
Diffraction tomography
Diffraction tomography is an inverse-scattering imaging method that reconstructs the internal structure of weakly scattering objects from diffracted waves, unlike ray-based tomography, with applications in geophysics, breast ultrasound, and cell imaging.
Diffusion chronometry
Diffusion chronometry is a geochemical method that converts chemical zoning profiles in minerals into durations of thermal events, most commonly the interval between magma recharge and eruption.
Digenite
Digenite is a copper sulfide mineral with formula Cu₉S₅ (Cu₁.₈S), an opaque blue to black ore mineral in primary and secondary copper deposits, named in 1844 and found at Sangerhausen, Germany, and Butte, Montana.
Digital elevation model
A digital elevation model (DEM) is a digital representation of the Earth's bare-ground topographic surface, excluding trees and buildings, used in flood modeling, road design, and topographic mapping.
Digital photogrammetry
Digital photogrammetry is a measurement technique that derives 3D coordinates and surface models from overlapping digital photographs, producing point clouds, elevation models, and orthomosaics for mapping and engineering.
Digital soil mapping
Digital soil mapping (DSM) is a geospatial method that predicts soil properties or classes across a landscape by fitting quantitative relationships between soil observations and environmental data layers.
Dike (geology)
A dike, also spelled dyke, is a sheet-like igneous intrusion that cuts across the layering of the rock it penetrates, the main path magma takes toward eruptions.
Dimmock v Secretary of State for Education and Skills
Dimmock v Secretary of State for Education and Skills is a 2007 High Court judicial review brought by Stewart Dimmock over distributing An Inconvenient Truth to English schools.
Diopside
Diopside is a calcium magnesium silicate pyroxene, MgCaSi₂O₆, common in olivine-rich basalts and metamorphosed limestones worldwide, cut into vivid green gemstones, and used to study Earth's mantle formation conditions.
Dioptase
Dioptase is a hydrated copper cyclosilicate mineral with intense emerald-green to blue-green crystals, named by René Just Haüy in 1797 and prized as a collector's specimen.
Diorite
Diorite is a coarse-grained intrusive igneous rock of intermediate composition, made mainly of plagioclase feldspar and dark minerals, with a speckled salt-and-pepper appearance; its fine-grained volcanic equivalent is andesite.
Dirección General de Aguas (Chile)
The Dirección General de Aguas (DGA) is the Chilean state agency, created in 1969 under the Ministry of Public Works, that manages the country's continental waters.
Disagreements on the intensity of tornadoes
Disagreements on the intensity of tornadoes, also known as tornado rating controversies, arise because tornado winds are inferred from damage, so different scales like the Fujita and TORRO systems assign different ratings.
Discharge (hydrology)
Discharge, also called streamflow or river discharge, is the volume of water passing a point in a channel per unit time, measured in cubic feet or meters per second.
Discrete fracture network model
A discrete fracture network (DFN) model simulates fluid flow and transport through fractured rock by representing each fracture explicitly, used in nuclear waste safety and hydraulic fracturing.
Discrete fracture network modeling
Discrete fracture network (DFN) modeling is a geological simulation method representing fractured rock as explicit networks of individual fractures to predict fluid flow and solute transport.
Disdrometer
A disdrometer, also called a distrometer, is an instrument that measures the drop size distribution and fall velocity of precipitation particles reaching the ground, used to calibrate weather radar.