Fold (geology)
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Fold (geology)
In structural geology, a fold is a stack of originally planar surfaces, such as sedimentary strata, that are bent or curved during permanent deformation. Folds in rocks vary in size from microscopic crinkles to mountain-sized folds. They occur as single isolated folds or in periodic sets (known as ''fold trains''). Synsedimentary folds are those formed during sedimentary deposition. Folds form under varied conditions of stress, pore pressure, and temperature gradient, as evidenced by their presence in soft sediments, the full spectrum of metamorphic rocks, and even as primary flow structures in some igneous rocks. A set of folds distributed on a regional scale constitutes a fold belt, a common feature of orogenic zones. Folds are commonly formed by shortening of existing layers, but may also be formed as a result of displacement on a non-planar fault (''fault bend fold''), at the tip of a propagating fault (''fault propagation fold''), by differential compaction or due to ...
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Folding Of Alternate Layers Of Limestone Layers With Chert Layers
Fold, folding or foldable may refer to: Arts, entertainment, and media * ''Fold'' (album), the debut release by Australian rock band Epicure *Fold (poker), in the game of poker, to discard one's hand and forfeit interest in the current pot *Above the fold and below the fold, the positioning of news items on a newspaper's front page according to perceived importance *Paper folding, or ''origami'', the art of folding paper Science, technology, and mathematics Biology *Protein folding, the physical process by which a polypeptide folds into its characteristic and functional three-dimensional structure **Folding@home, a powerful distributed-computing project for simulating protein folding *Fold coverage, quality of a DNA sequence *Skin fold, an area of skin that folds Computing *Fold (higher-order function), a type of programming operation on data structures *fold (Unix), a computer program used to wrap lines to fit in a specified width *Folding (DSP implementation), a transformation ...
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Folded Gyprock
Fold, folding or foldable may refer to: Arts, entertainment, and media * ''Fold'' (album), the debut release by Australian rock band Epicure *Fold (poker), in the game of poker, to discard one's hand and forfeit interest in the current pot *Above the fold and below the fold, the positioning of news items on a newspaper's front page according to perceived importance *Paper folding, or ''origami'', the art of folding paper Science, technology, and mathematics Biology *Protein folding, the physical process by which a polypeptide folds into its characteristic and functional three-dimensional structure **Folding@home, a powerful distributed-computing project for simulating protein folding *Fold coverage, quality of a DNA sequence *Skin fold, an area of skin that folds Computing *Fold (higher-order function), a type of programming operation on data structures *fold (Unix), a computer program used to wrap lines to fit in a specified width *Folding (DSP implementation), a transformation ...
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Wavelength
In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, troughs, or zero crossings, and is a characteristic of both traveling waves and standing waves, as well as other spatial wave patterns. The inverse of the wavelength is called the spatial frequency. Wavelength is commonly designated by the Greek letter ''lambda'' (λ). The term ''wavelength'' is also sometimes applied to modulated waves, and to the sinusoidal envelopes of modulated waves or waves formed by interference of several sinusoids. Assuming a sinusoidal wave moving at a fixed wave speed, wavelength is inversely proportional to frequency of the wave: waves with higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths. Wavelength depends on the medium (for example, vacuum, air, or water) that a wav ...
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Circle
A circle is a shape consisting of all points in a plane that are at a given distance from a given point, the centre. Equivalently, it is the curve traced out by a point that moves in a plane so that its distance from a given point is constant. The distance between any point of the circle and the centre is called the radius. Usually, the radius is required to be a positive number. A circle with r=0 (a single point) is a degenerate case. This article is about circles in Euclidean geometry, and, in particular, the Euclidean plane, except where otherwise noted. Specifically, a circle is a simple closed curve that divides the plane into two regions: an interior and an exterior. In everyday use, the term "circle" may be used interchangeably to refer to either the boundary of the figure, or to the whole figure including its interior; in strict technical usage, the circle is only the boundary and the whole figure is called a '' disc''. A circle may also be defined as a special ki ...
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Chevron (geology)
Chevron folds are a structural feature characterized by repeated well behaved folded beds with straight limbs and sharp hinges. Well developed, these folds develop repeated set of v-shaped beds. They develop in response to regional or local compressive stress. Inter-limb angles are generally 60 degrees or less. Chevron folding preferentially occurs when the bedding regularly alternates between contrasting competences. Turbidites, characterized by alternating high-competence sandstones and low-competence shales, provide the typical geological setting for chevron folds to occur. Perpetuation of the fold structure is not geometrically limited. Given a proper stratigraphy, chevrons can persist almost indefinitely. Fold process In response to compressional stress, geological beds fold in order to minimize dissipation of energy. Given an unconstrained bed, folding does so by correspondingly minimizing bending and thus develops a sinusoidal geometry. In a stratigraphic sequence, be ...
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Chevron Folds, Ireland
Chevron (often relating to V-shaped patterns) may refer to: Science and technology * Chevron (aerospace), sawtooth patterns on some jet engines * Chevron (anatomy), a bone * '' Eulithis testata'', a moth * Chevron (geology), a fold in rock layers * Chevron (land form), a sediment deposit across the earth's surface * Chevron nail, a rare transient fingernail ridge pattern seen in children * Chevron plot, a way of representing data Organisations * ''The Chevron'', former newspaper at the University of Waterloo, Ontario, Canada * Chevron Corporation, an American multinational energy corporation ** ''Chevron U.S.A., Inc. v. Natural Resources Defense Council, Inc.'', 467 U.S. 837 (1984), a United States Supreme Court case dealing with administrative law * Chevron Cars Ltd, a British racing car constructor * Chevron Engineering Ltd, a New Zealand car maker People * Philip Chevron (1957–2013), Irish singer/songwriter * The Chevrons, an American pop group Places * Chevron, ...
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Strike And Dip
Strike and dip is a measurement convention used to describe the orientation, or attitude, of a planar geologic feature. A feature's strike is the azimuth of an imagined horizontal line across the plane, and its dip is the angle of inclination measured downward from horizontal. They are used together to measure and document a structure's characteristics for study or for use on a geologic map. A feature's orientation can also be represented by dip and dip direction, using the azimuth of the dip rather than the strike value. Linear features are similarly measured with trend and plunge, where "trend" is analogous to dip direction and "plunge" is the dip angle. Strike and dip are measured using a compass and a clinometer. A compass is used to measure the feature's strike by holding the compass horizontally against the feature. A clinometer measures the features dip by recording the inclination perpendicular to the strike. These can be done separately, or together using a tool such a ...
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Flank & Hinge
Flank may refer to: * Flank (anatomy), part of the abdomen ** Flank steak, a cut of beef ** Part of the external anatomy of a horse * Flank speed, a nautical term * Flank opening, a chess opening * A term in Australian rules football * The side of a military unit, as in a flanking maneuver * Flanking, a sound path in architectural acoustics * Flanking region, a region of DNA in directionality * Rift flank (synonymous of rift shoulder In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-grabe ...), mountains belt on the sides of extensional rift basins See also * Flanker (other) {{disambiguation ...
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Concave
Concave or concavity may refer to: Science and technology * Concave lens * Concave mirror Mathematics * Concave function, the negative of a convex function * Concave polygon, a polygon which is not convex * Concave set * The concavity In calculus, the second derivative, or the second order derivative, of a function is the derivative of the derivative of . Roughly speaking, the second derivative measures how the rate of change of a quantity is itself changing; for example, ... of a function, determined by its second derivative See also

* {{disambiguation, math ...
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Inflection Point
In differential calculus and differential geometry, an inflection point, point of inflection, flex, or inflection (British English: inflexion) is a point on a smooth plane curve at which the curvature changes sign. In particular, in the case of the graph of a function, it is a point where the function changes from being concave (concave downward) to convex (concave upward), or vice versa. For the graph of a function of differentiability class (''f'', its first derivative ''f, and its second derivative ''f'''', exist and are continuous), the condition ''f'' = 0'' can also be used to find an inflection point since a point of ''f'' = 0'' must be passed to change ''f'''' from a positive value (concave upward) to a negative value (concave downward) or vice versa as ''f'''' is continuous; an inflection point of the curve is where ''f'' = 0'' and changes its sign at the point (from positive to negative or from negative to positive). A point where the second derivative vanishes but do ...
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Trough (geology)
In geology, a trough is a linear structural depression that extends laterally over a distance. Although it is less steep than a trench, a trough can be a narrow basin or a geologic rift. These features often form at the rim of tectonic plates. There are various oceanic troughs on the ocean floors. Examples of oceanic troughs * Benue Trough * Cayman Trough * Kings Trough * Hesperides Trough * Nankai Trough * Northumberland Trough * Okinawa Trough in the East China Sea * Rockall Trough and others along the rift of the mid-oceanic ridge * Salton Trough * South Shetland Trough * Suakin TroughDinwiddie, Robert et al. (2008) ''Ocean: The World's Last Wilderness Revealed'', London, Dorling Kindersley, page 452. in the Red Sea * Timor Trough See also * Walker Lane * Oceanic basin In hydrology, an oceanic basin (or ocean basin) is anywhere on Earth that is covered by seawater. Geologically, ocean basins are large  geologic basins that are below sea level. Most ...
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Crest (physics)
A crest point on a wave is the maximum value of upward displacement within a cycle. A crest is a point on a surface wave where the displacement of the medium is at a maximum. A trough is the opposite of a crest, so the minimum or lowest point in a cycle. When the crests and troughs of two sine waves of equal amplitude and frequency intersect or collide, while being in phase with each other, the result is called ''constructive'' interference and the magnitudes double (above and below the line). When in antiphase – 180° out of phase – the result is ''destructive'' interference: the resulting wave is the undisturbed line having zero amplitude. See also * Crest factor * Superposition principle * Wave In physics, mathematics, and related fields, a wave is a propagating dynamic disturbance (change from equilibrium) of one or more quantities. Waves can be periodic, in which case those quantities oscillate repeatedly about an equilibrium (res ... References *, 704 pages. Wa ...
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