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Vaca Muerta Formation
The Vaca Muerta Formation is a Late Jurassic to Early Cretaceous shale formation in Argentina's Neuquén Basin and the country's main oil and gas source rock.
Vadose zone
The vadose zone, also called the unsaturated zone, is the subsurface layer between the land surface and the water table, where pores hold both air and water.
Vaisala RS41
The Vaisala RS41 is a fourth-generation expendable radiosonde, a balloon-borne instrument made by Vaisala in Finland and introduced in 2013, that measures temperature, humidity, pressure, and wind.
Vaiyots-Sar
Vaiyots-Sar (Վայոցսար), also Dalik Tapa or Dar-Alages, is a pyroclastic cinder cone volcano in Vayots Dzor, Armenia, 2,575 m high, with Holocene lava flows, a 2000 BCE GVP eruption date, and a disputed 735 AD eruption legend.
Valanginian
The Valanginian is the second age of the Early Cretaceous, spanning 137.05 to 132.6 million years ago between the Berriasian and Hauterivian, named after Valangin, Switzerland.
Vale S.A.
Vale S.A., also known as Companhia Vale do Rio Doce (CVRD), is a Brazilian mining company founded by the government in 1942 and privatized in 1997.
Van Veen grab
The Van Veen grab is a bottom sampler with two scoop-like jaws closed by the pull of the deployment line, developed by Dutch engineer Johan van Veen.
Vanguard 2
Vanguard 2, launched by NASA on February 17, 1959, was the world's first weather satellite, designed to measure cloud cover over the daylight part of its orbit.
Variable source area
A variable source area is the part of a catchment that generates storm runoff, expanding and shrinking as soils become saturated, a concept developed by John D. Hewlett in the 1960s.
Variscan orogeny
The Variscan orogeny, also called the Hercynian orogeny, was a late Paleozoic mountain-building event caused when Gondwana and Laurussia collided, closing the Rheic Ocean and assembling Pangea.
Varve
A varve is an annually deposited sediment layer, usually a light summer and dark winter couplet, countable like tree rings; Gerard De Geer coined the term in 1912.
Varve chronology
Varve chronology counts annual sediment layers, called varves, to date and correlate sedimentary sequences with calendar-year precision; the Swedish geologist Gerard De Geer proposed it in 1884.
Vaterite
Vaterite is a metastable polymorph of calcium carbonate, the least stable of its three natural forms alongside calcite and aragonite, used in drug delivery and low-carbon cement.
Velocity analysis (seismology)
Velocity analysis is a seismic processing method estimating subsurface velocities from how reflection arrival times vary with source–receiver offset, producing a velocity spectrum of semblance values.
Velocity model building
Velocity model building is the process of constructing a 3D model of seismic wave speeds in the subsurface, iteratively updated so depth migration images reflectors at their true positions.
Vendaval
The vendaval is a stormy southwest wind of the southern Mediterranean coast of Spain and the Strait of Gibraltar, where it alternates with the easterly Levanter.
Ventifact
A ventifact is a rock cut and sometimes polished by wind-driven sand, named from the Latin ventus, occurring in deserts, coastal and periglacial environments, Antarctica, and on Mars.
Vermiculite
Vermiculite is a hydrated phyllosilicate mineral that expands into a light, accordion-like material when heated, used in insulation and gardening, and known for asbestos contamination at Libby, Montana.
Verninskoye
Verninskoye, also spelled Verninskoe, is a large orogenic gold deposit and open-pit mine in the Bodaibo District of Irkutsk Region, Russia, run by Polyus.
Verra
Verra is a nonprofit organization founded in 2007 and based in Washington, DC, that operates the Verified Carbon Standard, the world's leading carbon crediting program.
Vertical derivative (potential-field method)
In use since 1936, the vertical derivative is a transformation of gravity and magnetic data that narrows anomalies, helping interpreters locate the rock bodies that cause them.
Vertical electrical sounding
Vertical electrical sounding (VES) is a surface geophysical method that measures subsurface resistivity at increasing electrode spacings, producing a one-dimensional resistivity-versus-depth profile used mainly for groundwater prospecting.
Vertical seismic profile
A vertical seismic profile is a borehole geophysical method that records seismic arrivals from surface sources using receivers placed at depth in a well, providing higher-resolution velocity and imaging information than surface seismic surveys.
Vertical seismic profiling
Vertical seismic profiling (VSP) is a borehole seismic-reflection method using receivers clamped in a well, recording both downgoing and upgoing wavefields for depth calibration and imaging.
Vertisols
Vertisols are a soil order in USDA Soil Taxonomy, clayey soils rich in expanding clay that shrink when dry and swell when wet, opening deep cracks in most years.
Vibroseis
Vibroseis is a seismic surveying method in which a truck-mounted hydraulic vibrator radiates a frequency-modulated signal into the ground, replacing explosives; it was developed by Conoco in the 1950s.
Victor Hensen
Victor Hensen (Christian Andreas Victor Hensen, 1835–1924) was a German physiologist at the University of Kiel who coined the term "plankton" and founded quantitative plankton research.
VIIRS
VIIRS (Visible Infrared Imaging Radiometer Suite) is a scanning radiometer on US polar-orbiting satellites, first launched in 2011, that images Earth's land, oceans, and atmosphere twice daily.
Viktor Schauberger
Viktor Schauberger (1885–1958) was an Austrian forester, naturalist, and inventor who built log flumes and developed water- and air-driven machines based on what he called implosion.
Vine–Matthews–Morley hypothesis
The Vine–Matthews–Morley hypothesis (VMM), proposed in 1963 by Frederick Vine, Drummond Matthews, and Lawrence Morley, explains the ocean floor's striped magnetic anomalies as records of Earth's magnetic field reversals.